REVIEW ARTICLE

Psychometric Characteristics of Health-Related Quality-of-LifeQuestionnaires in Oropharyngeal Dysphagia

Angelique A. Timmerman • Renee Speyer •

Bas J. Heijnen • Iris R. Klijn-Zwijnenberg

Received: 16 July 2013 / Accepted: 14 December 2013 / Published online: 5 March 2014

� Springer Science+Business Media New York 2014

Abstract Dysphagia can have severe consequences for

the patient’s health, influencing health-related quality of

life (HRQoL). Sound psychometric properties of HRQoL

questionnaires are a precondition for assessing the impact

of dysphagia, the focus of this study, resulting in recom-

mendations for the appropriate use of these questionnaires

in both clinical practice and research contexts. We per-

formed a systematic review starting with a search for and

retrieval of all full-text articles on the development of

HRQoL questionnaires related to oropharyngeal dysphagia

and/or their psychometric validation from the electronic

databases PubMed and Embase published up to June 2011.

Psychometric properties were judged according to quality

criteria proposed for health status questionnaires. Eight

questionnaires were included in this study. Four are aimed

solely at HRQoL in oropharyngeal dysphagia: the deglu-

tition handicap index (DHI), dysphagia handicap index

(DHI0), M.D. Anderson Dysphagia Inventory (MDADI),

and SWAL-QOL, while the EDGQ, EORTC QLQ-STO 22,

EORTC QLQ-OG 25 and EORTC QLQ-H&N35 focus on

other primary diseases resulting in dysphagia. The psy-

chometric properties of the DHI, DHI0, MDADI, and

SWAL-QOL were evaluated. For appropriate applicability

of HRQoL questionnaires, strong scores on the psycho-

metric criteria face validity, criterion validity, and inter-

pretability are prerequisites. The SWAL-QOL has the

strongest ratings for these criteria, while the DHI0 is the

most easy to apply given its 25 items and the use of a

uniform scoring format. For optimal use of HRQoL ques-

tionnaires in diverse settings, it is necessary to combine

psychometric and utility approaches.

Keywords Oropharyngeal dysphagia � Health-related

quality of life � Questionnaires � Psychometric

characteristics � Deglutition � Deglutition disorders

Introduction

In clinical care there is a growing prevalence of chronic

over infectious diseases given the rise in life expectancy

since the 19th century due to better life conditions and

quality of care, resulting in a shift from cure to care when

measuring the effectiveness of treatment, i.e., from ‘‘life-

saving’’ to ‘‘life quality’’ [1, 2].

Quality of life (QoL) as a concept has increasingly been

recognized and used as an outcome measure of the effect of

(chronic) medical conditions (and their treatment) on daily

functioning, in agreement with the World Health Organi-

zation’s definition of health as ‘‘a state of complete phys-

ical, mental and social well-being, not merely the absence

of disease or infirmity’’ [3–5]. QoL has been broadly op-

erationalized as health-related quality of life (HRQoL) in

conceptual models and resulting instruments, and also

A. A. Timmerman (&)

Department of Family Medicine, Maastricht University,

PO Box 616, 6200 MD Maastricht, The Netherlands

e-mail: a.timmerman@maastrichtuniversity.nl

R. Speyer

School of Public Health, Tropical Medicine and Rehabilitation

Sciences, James Cook University, 43, James Cook Drive,

Townsville, QLD 4811, Australia

R. Speyer � B. J. Heijnen

Department of Otorhinolaryngology and Head and Neck

Surgery, Leiden University Medical Center, PO Box 9600,

2300 RC Leiden, The Netherlands

I. R. Klijn-Zwijnenberg

Emergency Medicine, Jeroen Bosch Hospital, Henri

Dunantstraat 1, 5223 GZ Den Bosch, The Netherlands

123

Dysphagia (2014) 29:183–198

DOI 10.1007/s00455-013-9511-8

includes symptom status, functional limitations (physical,

psychological, and social domains), and general health

perceptions as outcome measures. Functional health status

(FHS) is defined as the ability to perform tasks in multiple

domains (physical, social, role, and psychological func-

tioning) and measures the focus on (loss of) function due to

disease and/or treatment and the effects on daily life [6–9].

HRQoL measures are usually self-administered and

share a focus on the personal well-being of the patient in

broader personal and social contexts as relate to disease

(preferences for) treatment, disability, impairment, and

health [6–9]. Dysphagia is an example of a chronic con-

dition that usually has a big impact on the health and well-

being of patients because difficulty swallowing affects the

ability to eat and drink. The condition is often considered

symptom of another disease, e.g., head and neck cancer,

reflux, or Parkinson’s disease [10, 11]. In the literature, the

incidence of dysphagia in adults is described as ranging

from 6 to 50 % depending on the patient population studied

or the screening method used (e.g., videofluoroscopy or

fiberoptic endoscopy of the swallowing act) [12–14].

Dysphagia can have severe consequences for the patient’s

health as it can lead to dehydration, malnutrition, and

aspiration pneumonia [15, 16]. Dysphagia may show

effects on a psychological level, where risks of suffocation,

severe coughing, and vomiting may cause an increase in

anxiety and lower self-esteem [12]. From a social per-

spective, mealtimes may be very stressful and going to a

restaurant may no longer be a pleasure [17, 18].

All of these consequences have been shown to have an

impact on general health and QoL of the patient [11, 17].

This possible impact of dysphagia on HRQoL can be

integrated into the conceptual model shown in Fig. 1,

which shows the intermediate variables from a patient

perspective [6, 9, 19].

For the evaluation of HRQoL for dysphagia patients,

one can choose from a wide variety of (usually) patient-

administered questionnaires, from generic (usable for the

assessment of HRQoL in several diseases) to disease-spe-

cific (for specific diagnostic groups or patient populations)

[4, 20]. The advantages of questionnaires are that they are

easy to use, often self-administered, do not require much

time or effort compared to the information they provide

about the broader context of the patient, which may be

important for improvement in the quality of care [21, 22].

In particular, if the same questionnaire is used to evaluate

the natural course of disease and the effects of treatment, it

may be an important tool for identifying (hidden) problems

and facilitating shared clinical treatment decisions or for

monitoring change or response to treatment [5, 19].

In this systematic review, we give an overview of the

available disease-specific questionnaires for the evaluation

of HRQoL in oropharyngeal dysphagia but not esophageal

dysphagia or gastroesophageal reflux disease.

In order to give meaningful information on the QoL of

patients, the psychometric properties first need to be suffi-

cient. Second, it is important to gain a better understanding of

the differences in what HRQoL questionnaires measure and

provide a sound empirical basis for the selection of each

instrument. Therefore, the aim of this study was to describe

the measurement properties of HRQoL questionnaires that

are directed at patients suffering from oropharyngeal dys-

phagia and to assess the psychometric qualities of these

questionnaires. From the results of our review we recom-

mend the appropriate use of the questionnaires in both

clinical practice and research contexts.

Variables with a hypothesized impact on HRQoL from a patient perspective

Disease(Biological/

physiological)

Symptoms Dysphagia

Functional Health status

General health perceptions

Head & neck cancer, reflux,

Parkinson’s disease, etc.

- Dehydration - Malnutrition - Aspiration pneumonia, etc.

- Functional - Physical - Emotional - Social

Subjective perception of patient’s health

Fig. 1 A conceptual model showing the relationships between

dysphagia and HRQoL, assessed by patient-reported outcome mea-

sures [6, 9, 19]. The model may be read as ‘‘disease as clinical

diagnosis, resulting in dysphagia-related symptoms, effecting the FHS

of the patient, which may influence general health perceptions in an

either positive or negative manner’’. It is hypothesized that the disease

impacts on HRQoL through combined symptoms, FHS, and general

health perceptions, which can be reported on questionnaires by

patients and/or relatives

184 A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia

123

Methods

A literature search was conducted independently by two

reviewers using the electronic databases PubMed and

Embase. All available inclusion dates up to January 2010

were used, followed by another literature search for the

period between January 2010 and June 2011 as an update.

The search was limited to English, German, French,

Spanish, and Dutch publications. MeSH or thesaurus terms

were supplemented by using free-text words (for the period

after January 2009). In PubMed, the MeSH terms deglu-

tition disorders and QoL were combined, and in Embase,

the thesaurus terms dysphagia and QoL, quality of life

index were used. To retrieve the most recent publications

(after January 2009), one of the free-text words dysphagia,

deglutition, and swallow was combined with QoL in both

databases..

All abstracts were read and all full text articles that

about the development of HRQoL questionnaires related

to oropharyngeal dysphagia and/or the psychometric

validation of those questionnaires were retrieved. The

following articles were excluded: (1) reviews, case

reports, and editorials; (2) articles on questionnaires not

related to oropharyngeal dysphagia, e.g., esophageal

dysphagia; (3) articles on questionnaires solely concerned

with FHS; (4) articles on generic questionnaires; (5)

articles in which the questionnaire was not the subject of

the study; and (6) studies without an adult patient

population.

The reference lists of all included articles were sear-

ched for additional literature on the subject. For each

included questionnaire an extended search was executed

to check whether all articles concerning its development

and validation were retrieved. The names of each ques-

tionnaire were combined with each of the MeSH terms

psychometrics, reproducibility of results, validation

studies as topic, and validation studies [publication type]

in PubMed and the thesaurus terms reliability, psy-

chometry, validity, validation study, and instrument vali-

dation in Embase. Difference of opinion on whether an

article should be included were settled by group discus-

sion to reach a consensus. The psychometric properties of

the questionnaires were judged using the quality criteria

for the measurement properties of health status ques-

tionnaires proposed by Terwee et al. [23] and adapted by

Timmerman et al. [24] for application in otitis media

with effusion. Any indeterminate psychometric ratings

were discussed and resolved in a consensus meeting by

two of the authors (AT and RS). The definitions and

quality criteria of the ten psychometric properties used

for the evaluation of the questionnaires are shown in

Table 1.

Results

Findings of the Literature Search

The literature search using MeSH or thesaurus terms found

819 articles in PubMed and 966 in Embase. Another 112

articles were extracted from PubMed and 180 from Embase

using free-text words. From these articles a total of 1,923

references were found from both databases up to January

2010: 904 from PubMed articles and 1,019 from Embase

articles. The search update for the period January 2010 to

June 2011 yielded 827 articles, 73 from PubMed and 240

from Embase. When using free-text words, 210 and 304

references were found from PubMed and Embase articles,

respectively. Eighteen articles were included from the

initial search because they described the development of an

original questionnaire and/or the validation process of a

questionnaire related to oropharyngeal dysphagia. Table 2

lists the 14 questionnaires discussed in the included articles

and the reasons for final inclusion in or exclusion from this

study. The selection process excluded the following six

questionnaires: the University of Washington quality of life

questionnaire (UW QOL) [25], the head and neck quality

of life instrument (HNQOL) [26], and the European orga-

nisation for the research and treatment of cancer quality of

life questionnaire, module for the assessment of esophageal

cancer (EORTC QLQ-OES 18) [27] because they evaluate

only FHS, not HRQoL or they are related to head and neck

cancer or esophageal cancer; the functional assessment of

cancer therapy-head and neck scale (FACT-HN) [28] and

the Self-report symptom inventory [29] because they con-

tain too few items on oropharyngeal dysphagia-related

HRQoL; and the Klugman Quality of Life (QoL) ques-

tionnaire because it is an interview with open-ended

questions only [30].

The initially included questionnaires were SWAL-QOL

[31–33], M.D. Anderson dysphagia inventory (MDADI)

[34], deglutition handicap index (DHI) [35], dysphagia

handicap index (DHI0) [36], and the European dysphagia

group questionnaire (EDGQ) [12] and three questionnaires

that were modules developed for specific patient popula-

tions and used as a supplement to the European organisa-

tion for the research and treatment of cancer quality of life

questionnaire (QLQ-C30) [37]: the gastric cancer module

(EORTC QLQ-STO22) [38, 39], the esophageal, esoph-

agogastric junction, or gastric cancer module (EORTC

QLQ-OG25) [40], and the head and neck cancer module

(EORTC QLQ-H&N35) [41, 42]. (The number in the name

of the questionnaire indicates the number of items: 22

items in the QLQ-STO22, 25 in the QLQ-OG25, and 35 in

the QLQ-H&N35.) The final questionnaire was found in

the search update in June 2010: the DHI0 [36].

A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia 185

123

Descriptions of the Included Questionnaires

Descriptions of the eight included questionnaires are given

in Tables 3 and 4. The articles have been divided into those

that refer to the development of the questionnaire (Table 3)

and those that refer to the validation of the questionnaire

(Table 4) because different target populations were used

for development and validation in case of separate studies

for development and validation.

The included questionnaires are all self-administered

and intended for adults; only the EDGQ is an interview.

Target populations are adult patients of all ages with

Table 1 Definitions and quality criteria of required measurement properties of HRQoL questionnaires, based on the criteria by Terwee et al.

[23]

Property Definition Quality criteria

Content The concepts of interest are comprehensively represented by

the items in the questionnaire

Clear description provided of:

Measurement aim

Target population

Measured concepts

Item selection and reduction AND target population involved

in item selection

Criterion The scores of the questionnaire are related to a ‘‘gold

standard’’ measuring the target construct

Convincing arguments that the gold standard is really an

appropriate criterion measure AND correlation is C0.70

Construct The scores on a questionnaire relate to other measures in a

manner consistent with theoretical hypotheses concerning

measured concepts

The extent to which scores on a particular instrument relate to

other measures consistent with:

Theoretically derived hypotheses

Or expected differences between groups AND at least 75 % of

the results are in accordance with these hypotheses in a

sample of C50

Internal

consistency

A measure of homogeneity, indicates the extent to which

items in a (sub)scale are intercorrelated, measuring the same

construct

Factor analyses performed on:

Adequate sample size (n C 100) AND

n = 79 number of items OR Cronbach’s a calculated for each

dimension and between 0.70 and 0.95

Reproducibility

a. Agreement The degree to which an instrument is free of measurement

error by yielding stable scores over time in respondents

reporting no change

Comparison between scores of two related samples within

2–4 weeks showing no significant change (a C 0.005) after

correction for the number of measurements

OR test–retest correlations calculated have a minimum value of

0.70 at group level

b. Reliability The extent to which patients can be distinguished from each

other, despite measurement errors

ICC or weighted j C 0.70

Responsiveness The ability of a questionnaire to detect clinically important

change over time

Correlations in accordance with corresponding change in a

reference measure

OR changes in mean scores between ‘‘known groups’’ assessed

by the

Effect Size (ES [0.08)a or

Guyatt’s responsiveness ratio (RR C 1.96)b

Floor/ceiling

effects

The number of respondents achieving the lowest or highest

possible score

B15 % of respondents achieved the highest or lowest possible

scores in a sample of C50

Interpretability The degree to which one can assign qualitative meaning to

quantitative scores, translating what (change in) score is

clinically meaningful

Mean and SD scores presented of at least four subgroups of

patients and minimal important change (MIC) defined for a

sample C50 patients, e.g., scores of

A reference population (norm values)

Relevant subgroups expected to have different scores (clinical

diagnosis, age, etc.)

Scores before and after treatment

ICC intraclass correlation coefficienta ES mean change score/SD baseline scores. Values of [0.08 indicate a large responsiveness to changeb RR clinically important change is related to the between-subject variability in within-subject changes in stable subjects

186 A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia

123

oropharyngeal dysphagia (DHI [35], DHI0 [36], EDGQ

[12], and SWAL-QOL [31–33]), head and neck cancer

(MDADI [34] and EORTC QLQ-H&N35 [41, 42]), cancer

of the esophagus, the esophagogastric junction, or the

stomach (EORTC QLQ-OG25 [40]), and gastric cancer

(EORTC QLQ-STO22 [38, 39]). The patients included in

the development studies came mostly from private clinics

and hospitals across Europe or the US and ranged in

number from 52 patients for SWAL-QOL to 360 patients

for EDGQ. For the DHI there was one group of 96 patients

from one hospital (France) and a control group of 53

healthy people included (see Table 3). The EORTC QLQ-

STO22 was developed using a group of 58 patients and a

control group of 24 health professionals for item genera-

tion, and 115 patients with adenocarcinoma were used for

pretesting the developed questionnaire. The mean age of

the study populations in the nine studies listed in Table 3

ranged between 58 (MDADI) to 72 years (EDGQ). The

only exception was the DHI which had a mean age of

41 years for the patient group and 45 years for the control

group. A cross-sectional study design was used for the

development of all questionnaires.

The same target populations were used for development

and validation of the DHI, EORTC QLQ-OG25, and

MDADI, while there was no validation study for the EDGQ

(see Table 4). Four questionnaires were validated in separate

studies: the DHI0 [36] and SWAL-QOL [33] were validated

using a cross-sectional design, and the EORTC QLQ-STO22

[39] and EORTC QLQ-H&N35 [42] were validated by

prospective intervention studies. The populations used for

the validation studies were from multiple hospitals across

Europe and the US, except for the DHI0, which included data

from one hospital only. The patient populations of these val-

idation studies ranged from 214 for DHI0 to 500 for EORTC

QLQ-H&N35. For the validation of the SWAL-QOL

(n = 40) and the DHI0 (n = 74), a control group of healthy

volunteers from the general community was added instead of

a second palliative patient group, which was the case for the

EORTC QLQ-22 (n = 111). The DHI0 was administered to a

subset of patients with dysphagia on two occasions in a

follow-up study design (n = 63).

The mean ages of the patients in the development and

validation studies were quite comparable, the only excep-

tion being those for EORTC QLQ-STO22: mean age

60 years (range 22–80) in the development study and 65.1

(range 37–87) in the validation study because different

populations were used [38, 39]. For the validation studies,

the mean age of the patient groups ranged from 60 years

(range 20–92) for the females of the DHI0 to 67 years

(range 30–92) for the second patient group of the EORTC

QLQ-STO22.

Measurement Characteristics of the Questionnaires

The questionnaires were divided in two categories. The

first category contained four questionnaires that are aimed

solely at HRQoL of patients with oropharyngeal dysphagia:

DHI, DHI0, MDADI, and SWAL-QOL. These question-

naires are concerned primarily with HRQoL experienced

by the patient. The second group of questionnaires: the

EDGQ, EORTC QLQ-STO22, EORTC QLQ-OG25, and

EORTC QLQ-H&N35, combine FHS and HRQoL for

other primary diseases such as gastric (QLQ-STO22) or

head and neck cancer (QLQ-H&N35) and have a limited

number of dysphagia-related items or subscales. The

EDGQ was developed as part of an interview that assesses

the social and psychological burden of dysphagia, while the

EORTC QLQ-OG25 combines the EORTC QLQ-OES18

for esophageal [27] and the QLQ-STO22 for gastric cancer

[40], plus seven modified items.

Questionnaires Aimed at Oropharyngeal Dysphagia

Table 5 gives the measurement characteristics of the oropha-

ryngeal dysphagia-related HRQoL questionnaires. All ques-

tionnaires contain three domains, except for the SWAL-QOL

[33] which has ten domains related to oropharyngeal dyspha-

gia. These domains of the SWAL-QOL contain 44 items, plus

three anamnesis questions about food and liquid intake and a

Table 2 Overview of HRQoL questionnaires and reasons for inclu-

sion or exclusion in this study

Questionnaires Inclusion Exclusion

DHI [35] a

DHI0 [36] a

EDGQ [12] a

MDADI [34] a

SWAL-QOL [31–33] a

EORTC QLQ-STO22 [38, 39] b

EORTC QLQ-OG25 [40] b

EORTC QLQ-H&N35 [41, 42] b

EORTC QLQ-OES18 [27] c

HNQOL [26] c

UW-QOL [25] c

FACT-HN [28] d

Self-report symptom inventory [29] d

Klugman QoL questionnaire [30] e

a Mainly oropharyngeal dysphagia-related HRQoLb Combination of oropharyngeal dysphagia-related HRQoL and FHS

related to gastric, esophageal, or head and neck cancerc No oropharyngeal dysphagia-related HRQoL but FHS related to

head and neck cancer, esophageal cancerd Too few items on oropharyngeal dysphagia-related HRQoLe Interview with open-ended questions

A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia 187

123

Table 3 Description of studies for the development of questionnaires for the assessment of health-related quality of life (HRQoL) in oro-

pharyngeal dysphagia

Questionnairea References Target population Age (years) Study

design

Study population

DHI [35] Dysphagia I: Mean 41

Range 19–73

II: Mean 45

Range 21–86

Cross-

sectional

study

Hospital (France), unit speech and swallow

disorders: I: 96 patients with dysphagic symptoms

as a result from cancer in the upper aerodigestive

tract or neurological disease

Students and professors of an institute for

orthophonics, employees of a functional education

center, families of investigators: II: 53 healthy

controls

DHI0 [36] Dysphagia I: Females:

n = 33

Mean 60

Range 25–89

Males:

n = 44

Mean 63

Range 24–94

Cross-

sectional

study

Hospital (USA), division of Speech–Language

Sciences and Disorders I: 77 consecutive patients

with dysphagia (preliminary a version),

representing individuals with swallowing

problems, grouped into five categories based on

their medical diagnosis: 40 (52 %) with

neurological disorders, 10 (13 %) with head and

neck disorders, 6 (7.8 %) with esophageal

abnormalities, 3 (3.9 %) with gastroesophageal

reflux disorder (GERD), and 18 (23.4 %) with

other or unknown etiology

MDADI [34] Head and neck cancer I: Mean 58

SD 10

Range 21–80

Cross-

sectional

study

University cancer center (USA): I: 100 patients with

a neoplasm of the upper aerodigestive tract

SWAL-QOL [31, 32] Oropharyngeal dysphagia I: Mean 65.8

SD 15.4

II: Mean 67.9

SD 10.7

Cross-

sectional

study

Medical clinics and hospitals (USA): I: 52 patients

and caregivers for item development. II: 106

patients used for item reduction and preliminary

scaling

EDGQ [12] Dysphagia I: Mean 72

Range

55–80?

Cross-

sectional

study

Nursing homes and clinics (Germany, France, Spain,

UK): I: 360 patients with subjective dysphagia

symptoms

EORTC QLQ-

STO22

[38] Gastric cancer I: Mean 60.0

Range 22–80

II: Mean 65.6

Range 35–97

Cross-

sectional

study

Hospitals (UK, Spain, France, Germany): I: 24

health professionals and 58 patients representing a

range of disease stages and treatments were used

for item generation. II: 115 patients with

adenocarcinoma but representative of the full

spectrum of treatment modalities at a wide range

of intervals before, during, or after treatment were

used for pretesting

EORTC QLQ-

OG25

[40] Cancer of the oesophagus,

oesophageal-gastric junction

or stomach

I: Median 64

Range 27–85

II: Median 63

Range 30–83

III: Median

62

Range 34–84

Cross-

sectional

study

Hospitals [France (2), Germany (2), UK (2), Sweden

(1)]: a heterogeneous sample of 300 patients,

including patients undergoing a variety of

treatments and at different stages of treatment. I

(esophageal): 148 patients, II (esophagogastric

junction): 66 patients, and III (stomach): 86

patients

EORTC QLQ-

H&N35

[41] Head and neck cancer I: Mean 62

Range 26–78

II: Mean 62

Range 40–82

Cross-

sectional

study

I: 40 patients from Scandinavian hospitals were used

for item development. II: 60 in- or outpatients

receiving treatment or follow-up in one of six

hospitals [UK, Norway, Sweden (2), Denmark,

Belgium] were used for pretesting

a SWAL-QOL swallowing disorders quality-of-life survey; MDADI M.D. Anderson dysphagia inventory; DHI deglutition handicap index; DHI0

dysphagia handicap index; EDGQ European Dysphagia Group Questionnaire; EORTC QLQ-STO22 European Organization for Research and

Treatment of Cancer Quality of Life Questionnaire-Stomach cancer module; EORTC QLQ-OG25 European Organization for Research and

Treatment of Cancer Quality of Life Questionnaire-Oesophageal and Gastric cancer module; EORTC QLQ-H&N35 European Organization for

Research and Treatment of Cancer Quality of Life Questionnaire-Head and Neck Cancer module

188 A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia

123

question about global health. The MDADI [34] consists of 20

items subdivided in emotional, functional, and physical health,

while there is one global item about limitations to daily activ-

ities due to swallowing ability. The DHI [35] consists of the

physical, functional, and emotional domains comprising 30

items, while the DHI0 [36] contains emotional, functional, and

physical scales comprising 25 items plus one severity item.

Most items of the SWAL-QOL involve the impact of

oropharyngeal dysphagia, except for five items related to

fatigue and sleep. For the MDADI, DHI, and DHI0, all

items are oropharyngeal dysphagia-specific. According to

the definition of HRQoL and FHS given in the Introduc-

tion, more than 50 % of the items of these four question-

naires are about symptoms and functional abilities (FHS)

resulting from dysphagia: 25 items for the SWAL-QOL, 12

for the MDADI, 18 for the DHI, and 17 for the DHI0.Response options for the DHI, MDADI, and SWAL-QOL

range from 1 to 5 on a 5-point Likert scale, i.e., from strongly

agree to strongly disagree. The DHI0 has three response

options: never, sometimes, and always. The total score for the

SWAL-QOL can range from 0 (least favorable state) to 100

(most favorable state) while that for the MDADI can range

from 20 (extremely low functioning) to 100 (high function-

ing). For the DHI and the DHI0, the lowest score is 0 (least

disabled) and the highest possible scores are 100 and 120

(most disabled), respectively. For two items of the MDADI, ‘‘I

do not feel self-conscious when I eat’’ (emotional subscale)

and ‘‘I feel free to go out to eat with my friends, neighbours and

relatives’’ (functional subscale), the scoring is reversed so that

higher scores reflect better functioning.

Questionnaires for Primary Diseases that often Result

in Oropharyngeal Dysphagia

Measurement characteristics of questionnaires aimed at

diseases that often result in oropharyngeal dysphagia are

given in Table 6. There is one interview (EDGQ [12]) and

three questionnaires (QLQ-STO22 [39], QLQ-OG25 [40],

QLQ-H&N35 [41, 42]). The EDGQ is aimed at the impact

of dysphagia on social and psychological well being. The

interview consists of 28 items covering five domains. One

of these domains, ‘‘personal feelings and importance’’,

contains four items and four contingency questions (to be

answered only if the patient answered ‘‘yes’’ to a foregoing

question) related to oropharyngeal dysphagia and HRQoL,

e.g., ‘‘Would you say that eating is an enjoyable part of

your day?’’ Response options are ‘‘yes’’, ‘‘no’’, and ‘‘do not

know’’ and no scoring range is available. The QLQ-

STO22, QLQ-OG25, and QLQ-H&N35 are all question-

naire modules to be used as supplements to the EORTC

QLQ-C30 questionnaire [37]. These questionnaires all

contain multiple-item scales and some single items in

differing numbers. The QLQ-STO22, QLQ-OG25, and

QLQ-H&N35 use the same 4-point scale response for-

mat—not at all, a little, quite a bit, and very much—for

most items, and the QLQ-H&N35 also has a yes/no

response format for the last five questions. Scores range

from 0 to 100 for the QLQ-OG25 and QLQ-H&N35 and

from 0 to 84 for the QLQ-STO22. The questionnaires

contain dysphagia-related HRQoL items that address the

impact of dysphagia on HRQoL; they are concerned with

the impact of the eating and/or swallowing problem on the

patient’s self-esteem and social life, which may result in

feelings of anxiety and/or shame. The QLQ-STO22 has

three such items, e.g., ‘‘Have you had discomfort when

eating?’’ The EORTC QLQ-OG25 has the same three

dysphagia-related HRQoL items and one additional item:

‘‘Have you had difficulty eating?’’ Only the QLQ-H&N35

summarizes the HRQoL items related to dysphagia in the

social eating domain, which contains four items: ‘‘Have

you had trouble eating?’’, ‘‘Have you had trouble eating in

front of your family?’’, ‘‘Have you had trouble eating in

front of other people?’’, and ‘‘Have you had trouble

enjoying your meals?’’.

Psychometric Qualities of Questionnaires Aimed

at Oropharyngeal Dysphagia

The psychometric properties of the questionnaires aimed

solely at the impact of oropharyngeal dysphagia were

judged using quality criteria that are used for health status

questionnaires [23, 24]. The EDGQ, QLQ-STO22, QLQ-

OG25, and QLQ-H&N35 did not contain the necessary

number of items related to oropharyngeal dysphagia for an

appropriate psychometric judgment of the impact of oro-

pharyngeal dysphagia. Ratings for the DHI [35], DHI0 [36],

MDADI [34], and SWAL-QOL [33] are given in Table 7.

The development and validation studies of the question-

naires aimed at oropharyngeal dysphagia used a cross-

sectional design, which implies that no clinically important

changes over time (responsiveness) could be assessed. The

psychometric qualities of each questionnaire are discussed

in the following subsections.

Deglutition Handicap Index (DHI)

For the DHI, clear descriptions of the goal of the mea-

surement and the measured concepts of the questionnaire

were provided. Information about the target population was

presented; however, the development and item selection

were not described, so it is not clear whether the target

population was involved in item selection, resulting in an

indeterminate rating for content validity. Internal consis-

tency also received an indeterminate rating because both

quality criteria were not fulfilled, the sample sizes for

healthy subjects (n = 53) and patients (n = 96) were

A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia 189

123

insufficient since the questionnaire contained 30 items,

which necessitated at least 210 subjects (7 9 30 items).

Cronbach’s a coefficients were [0.70 for the patient

sample, except for the physical domain (a = 0.60). The

combined patient and healthy samples had an a value of

0.81 for the physical domain, which is elevated by the

Table 4 Description of measurement characteristics of validation studies related to questionnaires for the assessment of health-related quality of

life (HRQoL) in dysphagia

Questionnaire Refs Target

population

Age (years) Study design Study population

DHI [35] Study for both development and validation: measurement characteristics in Table 3

DHI0 [36] Dysphagia I: experimental

group

A. Females:

n = 110

Mean 60, SD 16,

Range 20–92

B. Males:

n = 104

Mean 66, SD 13,

Range 19–96

II: controls

A. Females:

n = 40

Mean 60, SD 13,

Range 30–86

B. Males: n = 34

Mean 54, SD 14,

Range 30–80

I–II: cross-sectional

study

Hospital (USA), division of Speech–Language

Sciences and Disorders: I: 214 consecutive

patients with dysphagia (final b version) grouped

into six categories based on their medical

diagnosis: 72 (33.6 %) with neurological

impairment, 76 (35.5 %) with head and neck

disorders, 6 (2.8 %) with esophageal

abnormalities, 23 (10.7 %) with gastroesophageal

reflux disorder (GERD), 9 (4.2 %) with respiratory

disorders, and 28 (13.1 %) with other etiologies

such as diabetes, post-bariatric surgery, globus

sensation, or unknown causes

Individuals selected from within the community,

without dysphagia, history of head and neck

cancer, or surgery (with the exception of

tonsillectomy), history of neurological problems,

or feeding tube placement. II: 74 controls

III: Retest group

(n = 63)

A. Females:

n = 40

Mean 60

B. Males: n = 23

Mean: n = 66

III: Follow-up study

Time between

administrations of

the DHI was

7–116 days

(Mean = 36,

SD = 32,

Median = 21)

In a subgroup (of the experimental group) the DHI

was administered two times to individuals with

dysphagia who were not undergoing any

intervention for swallowing. Within this subgroup,

26 (41.3 %) had a diagnosis of neurological

disorder, 22 (35 %) with head and neck disorder, 1

(1.6 %) with esophageal abnormality, 7 (11.1 %)

with gastroesophageal reflux disorder (GERD), 7

(11.1 %) with other diagnoses. III: 63 patients

MDADI [34] Study for both development and validation: measurement characteristics in Table 3

SWAL-QOL [33] Oropharyngeal

dysphagia

I: Mean 66

SD 13

II: Mean 73

Cross-sectional study Medical outpatient speech, swallowing, neurology

clinics, ENT and other surgery clinics, VA

hospitals, (university) medical centers (USA): I:

386 patients with mechanical or neurological

oropharyngeal dysphagia

General community, hospital volunteer department,

and elder-hostel education program (USA): II: 40

healthy controls

EDGQ [12] No validation study present

EORTC

QLQ-

STO22

[39] Gastric cancer I: Mean 65

Range 37–87

II: Mean 67

Range 30–92

Prospective

intervention study

14 institutions in 8 different countries: 219 gastric

cancer patients. I: 108 (potentially curative)

patients, II: 111 (palliative treatment) patients

EORTC

QLQ-OG25

[40] Study for both development and validation: measurement characteristics in Table 3

EORTC

QLQ-

H&N35

[42] Head and neck

cancer

I: Mean 61

Range 18–88

Median 64

Prospective

intervention study

6 hospitals: I: 500 patients; 111 patients (Norway)

and 248 patients (Sweden) with head and neck

cancer, 141 patients (The Netherlands) with

squamous cell carcinoma

190 A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia

123

findings for the healthy sample (a = 0.74). For the

assessment of floor and ceiling effects, which indicate that

in the respective domains more than 15 % of respondents

achieved the highest or the lowest possible scores, scoring

patterns on individual items were used. For the DHI, this

indicates that for the healthy sample, the floor effects were

present for the ten items in the physical domain, the only

domain sampled in both groups. The number of subjects

with lowest possible score of ‘‘0’’ (never) ranged from 35

(66 %) to 49 (92 %) subjects, while the highest score was

‘‘2’’ (sometimes) on all items. For the patient sample, both

floor and ceiling effects were present. The pattern of floor

effects was convincing because it was present on all items

of the three domains, ranging from 19 (20 %) to 75 (78 %)

subjects with a score of ‘‘0.’’ Ceiling effects were less

extreme and differed between domains. For the physical

domain, the ceiling effects were present on four items;

between 18 (19 %) and 33 (34 %) of the subjects scored

‘‘4’’ (always), the highest possible score. The emotional

domain contained ceiling effects on three items, and a

range of 17 (18 %)–20 (21 %) subjects had a maximum

score. Ceiling effects were the strongest in the functional

domain, with 15 (16 %)–44 (48 %) scoring ‘‘4’’ (always)

on four items. DHI has not been related to another measure

resulting in an indeterminate rating for construct validity.

Only correlations between the domains and total DHI were

described, ranging from 0.59 between the functional and

physical domains to 0.67 between the functional and

emotional domains. Values were [0.80 between all

domains and total DHI scores, as should be expected for a

questionnaire. Criterion validity was calculated by corre-

lating the scores of the domains with different measures.

For the physical domain, scores were compared to the

physical pathological mechanisms assessed by videofluo-

roscopic examination, with no significant results (r = 0.17,

0.25, 0.29). The functional domain correlated with the

nutritional status and significant values were found for

meal duration (r = 0.32, p = 0.035), but the correlation

was reversed for the degree of severity (r = –0.51,

p = 0.018) with the functional and physical domains

(r = –0.38, p = 0.028), indicating that severity was less in

the case of higher scores on the functional and physical

domains. Correlation between the emotional domain and

the COOP/WONCA cards, which evaluate QoL in patients

with chronic diseases, was small (r = 0.40, not signifi-

cant), which may be due to the use of this generic measure

for HRQoL in chronic conditions [43, 44]. There was no

information that could be used to assess the reproducibility,

reliability, and interpretability of the DHI.

Dysphagia Handicap Index (DHI0)

The DHI0 received an indeterminate rating on content

validity, although clear descriptions were provided of the

measurement aim, target population, measured concepts,

and item reduction. It is not clear whether the target pop-

ulation was involved in final item selection or that their

scores were used only on the preliminary version to

Table 5 Measurement characteristics of dysphagia-specific questionnaires for the assessment of HRQoL

Questionnaire Domains (No. of items) Scales Item

no.

Response options Range

of

scores

DHI [35] Physical (10), functional (10), emotional (10) 3 30 Never, almost never, sometimes,

almost always, always

0–120

DHI0 [36] Physical (9), functional (9), emotional (7) 3 ? 1

severity

item

25 Never, sometimes, always 0–100

MDADI [34] Emotional (6), functional (5), physical (8)a 3 ? 1

global

item

20 Strongly agree, agree, no opinion,

disagree, strongly disagree

20–100

SWAL-QOL

[31–33]

Burden (2), eating duration (2), eating desire (3), food

selection (2), communication (2), fear (4), mental health

(5), social functioning (5), fatigue (3), sleep (2)

10 44 Strongly agree, agree, uncertain,

disagree, strongly disagree

Very much true, quite a bit true,

somewhat true, a little true, not at all

true

Almost always, often, sometimes,

hardly ever, never

All of the time, most of the time,

some of the time, a little of the time,

none of the time

0–100

a Reversed scoring for two items of the MDADI: ‘‘I do not feel self-conscious when I eat’’ (emotional subscale) and ‘‘I feel free to go out to eat

with my friends, neighbors and relatives’’ (functional subscale)

A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia 191

123

Table 6 Measurement characteristics of questionnaires for the assessment of health related quality of life (HRQoL) in primary diseases often

resulting in oropharyngeal dysphagia

Questionnaire Domains (no. of items) Scales Item

no.

Dysphagia-related HRQoL

items

Response options Range of

scores

EDGQ [12] 1. Background data (3)

2. Eating habits (4 ? 1a)

3. Personal feelings and

importance (4 ? 4a)

4. Seeking help (5 ? 3a)

5. Medical status (3 ? 1a)

5 multiple-item scales 28 Domain: ‘‘personal feelings

and importance’’

Yes, no, don’t know NA

QLQ-STO22

[38, 39]

1. Dysphagia (4)

2. Pain (3)

3. Reflux (3)

4. Eating (5)

5. Anxiety (3)

6. Single items (3) ? 1a

5 multiple-item scales,

3 single items

22 1. Discomfort when eating

2. Trouble enjoying meals

3. Trouble eating in front of

other people

Not at all, a little, quite a

bit, very much

0–84

QLQ-OG25

[40]

1. Dysphagia (3)

2. Eating restrictions (4)

3. Reflux (2)

4. Odynophagia (2)

5. Pain and discomfort (2)

6. Anxiety (2)

7. Single items (10)

6 multiple-item scales,

10 single items

25 1. Trouble enjoying meals

2. Difficulty eating

3. Discomfort when eating

4. Trouble with eating in

front of other people

Not at all, a little, quite a

bit, very much

Answer Q25 only if hair

loss present

0–100

QLQ-H&N35

[41, 42]

1. Pain (4)

2. Swallowing (4)

3. Senses (2)

4. Speech (3)

5. Social eating (4)

6. Social contact (5)

7. Sexuality (2)

8. Single items (11)

7 multiple-item scales,

11 single items

35 Domain ‘social eating’:

1. Trouble eating

2. Trouble eating in front of

family

3. Trouble eating in front of

other people

4. Trouble enjoying your

meals

Not at all, a little, quite a

bit, very much

Q31–35: no/yes

0–100

a Contingency question: Only to be answered if the foregoing question has been answered ‘‘yes’’

Table 7 Summary rating of psychometric qualities for questionnaires evaluating health-related quality of life (HRQoL) in oropharyngeal

dysphagia

Questionnaire

rating a,bContent

validity

Criterion

validity

Construct

validity

Internal

consistency

Reproducibility Responsiveness Floor or ceiling

effect

Interpretability

a. Agreement

b. Reliability

DHI [35] ? - - ? a. 0

b. 0

NA ? 0

DHI0 [36] - ? ? ? a. ?

b. ?

NA ? ?

MDADI [34] ? - ? ? a. ?

b. 0

NA - ?

SWAL-QOL

[33]

? ? ? ? a. ?

b. ?

NA ? ?

a ? positive rating, ? indeterminate rating, - negative rating, 0 no information available, NA not applicableb Indeterminate rating (?) means doubtful design or method (i.e., lacking a clear description or important methodological weakness) or only

fulfilling part of the requested psychometric quality

192 A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia

123

construct the final questionnaire version. Agreement was

assessed by test–retest correlations (Pearson’s correlation

coefficient) and all values were between 0.75 and 0.86 as

requested, but the period between tests, which ranged from

7 to 116 days (mean 36, SD 32.2), was less than 2 weeks

for part of the sample, resulting in an indeterminate rating.

No ceiling effects (\2.3 %) were present for the DHI0, but

the functional (24.8 %) and emotional (32.7 %) domains

showed floor effects, indicating that more than 15 % of

respondents received the lowest possible scores. Strong

psychometric qualities were found for internal consistency

and reliability. For internal consistency, sample size was

larger than 100 (n = 7 9 25 items = 175 items) and all

Cronbach’s a values were between 0.78 (physical) and 0.94

(total DHI0 score). Reliability received a positive rating

because the ICC values ranged between 0.75 (emotional)

and 0.86 (functional) for all domains and the total DHI0

score. Regarding validity aspects, it can be stated that

criterion validity was assessed by a measure of clinical

severity, a videofluorographic swallowing study (VFS). A

subgroup of 60 patients was assessed and subdivided in

three subgroups of normal (n = 19), mild (n = 29), and

moderate/severe (n = 12) based on the scores of the VFS.

The overall difference between these clinical severity

groups was significant for the mean total DHI0 (p = 0.003)

and the functional (p = 0.001), emotional (p = 0.009), and

physical (p = 0.049) subscales, as calculated with

ANOVA methods, resulting in a positive rating. Construct

validity received a positive rating and was measured in two

ways (n [ 50). First, Pearson correlations between several

subscales were calculated, with the highest correlation

between the emotional and functional subscales (r = 0.77)

and lowest between the physical and emotional subscales

(r = 0.66), while the correlation between the physical and

functional subscales was intermediate (r = 0.72). These

results imply that the functional limitations have more of

an impact on emotional functioning than the physical

limitations, which should be expected because of the

impact on social functioning, one of the greatest handicaps

caused by oropharyngeal dysphagia [17, 18]. Second,

Wilcoxon two-sample tests were used to assess the dif-

ference in DHI0 scores between the dysphagia and control

groups. The control group had significantly lower scores

for total DHI0 and subscales than the dysphagia group

(p \ 0.001). In the control group, almost all participants

responded ‘‘never’’ on the subscales, which is the expected

difference between patients and a population from the

general community. Interpretability received a positive

rating due to the presence of clinically meaningful scores

for four clinical severity subgroups (normal, mild, moder-

ate, and severe), as discussed under criterion validity. The

self-reported severity rating of the DHI0 was also grouped

into the following categories for the 214 dysphagia

patients: 1 = normal, 2 and 3 = mild, 4 and 5 = moder-

ate, and 6 and 7 = severe. The differences for these

severity groups were significant for total and all subscales

(p = 0.001), and post hoc analyses showed that all pairwise

comparisons were significant as well (p = 0.05).

M.D. Anderson Dysphagia Inventory (MDADI)

Measurement aim, target population and measured concepts

were all described for the MDADI, while the target popu-

lation was involved in item selection [34]. Information about

the process of item selection and reduction was absent,

resulting in an indeterminate rating for content validity.

Using a sample of 100 patients, Spearman correlation coef-

ficients were calculated between the domains of the MDADI

and the SF-36, which is a short-form general health survey of

the Medical Outcomes Study (MOS), as a measure of con-

struct validity [45, 46]. The results were in accordance with

expected hypotheses: Since the MDADI is intended to

measure the psychosocial aspects of dysphagia, the signifi-

cant correlations of the SF-36 mental components (i.e., social

functioning, role-emotional, and mental health) scores were

as expected with the domains global (0.44), emotional

(0.54), functional (0.51), and physical (0.54). There is no

information about the reproducibility aspect of the property

reliability present, resulting in a ‘‘0’’ rating, while the

property agreement received a positive rating. Correlations

within a 2-week period were 0.85 for both emotional and

physical domains, 0.89 for the functional domain, and 0.93

for the global domain. Both internal consistency and inter-

pretability received indeterminate ratings. Factor analyses

were performed on 100 patients, which is \7 times the

number of items, which is 20. Although the overall Cron-

bach’s a coefficient was 0.96, two values were\0.70: for the

functional domain it was 0.58 and for the emotional domain

it was 0.69. Interpretability was determined in only three

subgroups (site and pathological features of the head and

neck tumor and time elapsed since the last treatment), and

some of the subsamples were smaller than 50. An indeter-

minate rating was also given for floor and ceiling effects

because it was not clear from the table and text in the article

whether the numbers were questionnaire scores or patients

(n), which made judging this psychometric quality impos-

sible. Criterion validity received a negative rating because

there was no psychometric information for the Performance

Status Scale (PSS), a clinician-rated instrument that is used

as the gold standard. All correlations were\0.70, from 0.47

for the PSS eating in public domain and the MDADI global

domain to 0.61 for the PSS normalcy of diet and the MDADI

functional domain.

A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia 193

123

SWAL-QOL

Content validity and interpretability were the strongest

qualities for the SWAL-QOL: all criteria regarding mea-

surement aim, target population, measured concepts, and the

processes of item selection and reduction were described,

while the target population was involved in item selection

[33]. Relevant subgroups were selected for interpretability:

(1) dysphagic patients—normal swallowers, (2) dysphagic

patients with oral nutrition—tube feeding, (3) dysphagic

patients differing with respect to what food texture and liquid

consistency can be handled, and (4) relationship between

symptom severity and QoL. Differences between groups

were significant for almost all scores with the SWAL-QOL

(p \ 0.0001), except for domains related to liquid consis-

tency (p \ 0.10) and four domains related to tube feeding

status (p [ 0.060). For the SWAL-QOL domains, the rela-

tionship with symptom severity, considered a gold standard

for criterion validity, is highly significant (p = 0.0001). The

SF-36 was used to calculate convergent validity with the

SWAL-QOL domains, considered to be an indicator of

construct validity [45, 46]. The correlations between SWAL-

QOL domains and the SF-36 measures health perceptions,

social function, loneliness, and mental health are all signif-

icant at p \ 0.05 and range between 0.11 for the relationship

between SF-36 health perceptions and SWAL-QOL burden

and eating duration and 0.56 for the relationship between SF-

36 loneliness and SWAL-QOL social functioning. Internal

consistency was assessed with an adequate sample size

(n [ 100), and Pearson’s correlation coefficients were

mainly [0.70, indicating construct homogeneity. Repro-

ducibility, containing the properties agreement and reli-

ability, received an indeterminate rating. Agreement was

assessed by Pearson correlation coefficient within a 2-week

time frame, with values ranging from 0.60 to 0.91 for all

SWAL-QOL domains with burden (0.60) and eating dura-

tion (0.64) having values\ .70. Intraclass correlation (ICC),

a measure of reliability, ranged from 0.59 to 0.91, with the

values for burden (0.59) and eating duration (0.64) below

0.70. Ceiling effects were present for five of the ten domains

of the SWAL-QOL (food selection, social functioning, eat-

ing desire, communication, and sleep) and floor effects were

present for two domains (burden and eating duration).

Discussion

Evaluation of the Psychometric Qualities

of Questionnaires Evaluating HRQoL in Dysphagia

The psychometric qualities of questionnaires aimed solely

at HRQoL in oropharyngeal dysphagia were assessed. This

choice was informed by strong associations between

indicators of a condition, such as dysphagia, and evaluation

measures that are conceptually proximal to the disease (i.e.

disease-specific questionnaires) [4, 47].

The DHI0 and SWAL-QOL received the strongest psy-

chometric ratings, at least on all validity aspects and the

interpretability of the questionnaire. This implies that the

SWAL-QOL measures homogeneously what it is supposed to

measure in an appropriate target population of patients with

dysphagia. The SWAL-QOL differentiates on relevant clini-

cal characteristics such as normal swallowing, manner of food

intake, food texture, liquid consistency, and symptom sever-

ity. Shortcomings were found in reproducibility (stability over

time, distinguishing between patients) and floor and ceiling

effects for the score ranges. For several items of the SWAL-

QOL, patients’ scores may have indicated that they were

functioning better (underscoring) or worse than they experi-

enced (overscoring); this was a weakness of the other ques-

tionnaires as well. The DHI0 received positive ratings on

almost all validity aspects and the ability to distinguish

between patients at one point. Clinically meaningful sub-

groups were used to evaluate clinical severity through both

self-assessment and a measure of clinical severity, which is

closely related to the health condition (interpretability). Only

the face validity of the DHI0 was doubtful because it was not

clear if the target population was involved in item selection.

Comparison of the DHI0 and SWAL-QOL with the MDADI

and especially the DHI was complicated by weak psycho-

metric qualities or lack of information on validity aspects (e.g.,

content, criterion), internal consistency, floor and ceiling

effects, and interpretability.

The cross-sectional design of all included studies makes

conclusions about the ability to assess changes over time

(responsiveness) difficult. Responsiveness is an indicator

that is difficult to assess through changes in perceptions of

disease, which complicates the assessment of intervention

effects [48]. Another weakness for all the questionnaires is

the lack of information or indeterminate ratings for repro-

ducibility, which also contains valuable information about

changes over time. From a psychometric perspective, one

can draw conclusions about the possibility to discriminate

between patients at only one point in time, which makes

the SWAL-QOL and DHI0 appropriate for screening pur-

poses or needs assessment. No final conclusions can be

drawn about within-subject variability over time, an

important measure for the evaluation of the intervention

effects of a HRQoL questionnaire.

Applicability of a Questionnaire for Dysphagia Impact:

Constructs, Domains, Comprehensiveness, Scoring

Formats, Internal Standards, and Utility

The intrinsic value of a HRQoL questionnaire is closely

linked to its application and is dependent on a match

194 A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia

123

between intended purposes, the information the instrument

provides, and ease of use. Therefore, measurement prop-

erties need to be considered as well in order to provide a

sound judgment based on the needs in a specific context

such as research, clinical practice, or quality assurance

[19]. For the development of the SWAL-QOL, HRQoL in

oropharyngeal dysphagia was defined as ‘‘an overall state

of well-being that is a composite of the ability to fulfill

physical, role and social activities, and psychological

effectiveness with which one performs these activities,

satisfaction with health care services related to dysphagia

treatment and symptom status’’ [31, 49]. This definition

seems to cover the range of content properties needed in a

HRQoL questionnaire applied to assess dysphagia impact,

although the boundaries of definition depend on why one is

assessing the particular concerns of patients [22]. A dis-

tinction has been made between FHS and HRQoL for the

items of all questionnaires included in this study. It can be

stated that these constructs are quite proximal and in need

of clear definitions and boundaries to enable appropriate

evaluation. Ware [4] describes a so-called specific–generic

continuum, with physical and mental symptoms resulting

in physical limitations (FHS) and psychological distress

(HRQoL), respectively, combined in a subjective overall

evaluation of health in general (see also Fig. 1) [4, 7, 9].

The continuum implies that both physical and mental

symptoms need to be evaluated in order to get a complete

picture of the impact of oropharyngeal dysphagia experi-

enced by the patient. In the psychometrically evaluated

questionnaires this was the case, while only in the SWAL-

QOL was there one global question about general health,

representing the generic end of the continuum. All ques-

tionnaires contained items related to functional, physical,

and emotional health with respect to dysphagia, ranging

from 6 to 10 items for each domain. Only the SWAL-QOL

clearly defines the content of scales, e.g., eating duration,

eating desire, and food selection, mostly represented by

2–5 items for each construct. Multidimensional HRQoL

questionnaires are accurate and responsive for specific

patient outcomes only, if subscales are selected in accor-

dance with individual patient needs [5]. Given a positive

rating for internal consistency, the SWAL-QOL is infor-

mative for the assessment of the full range of possible

dysphagia effects in clinical care. The DHI0, also a

homogeneous measure, is easier to score due to three

response options, with the same textual anchors for all

items, which is not true for the 5-point scoring format of

the SWAL-QOL.

For all applications, meaningful interpretation of scores

may be easier if there is some estimate of the relative

importance of each of the included (impact) domains in a

questionnaire [50]. The concept of severity has been

described as an important causal mediator in scoring the

impact of a condition on domains that impact HRQoL [6, 7,

9]. The DHI0 contains a response scale ranging from nor-

mal to severe problem (score = 1–7) in response to the

item ‘‘swallowing difficulty’’ at the end of the question-

naire. The SWAL-QOL and the MDADI question severity

in terms of impact on ‘‘dealing with a swallowing prob-

lem’’ (only SWAL-QOL) and ‘‘experienced limitations in

daily life’’, both scored on a reversed 5-point scale (i.e.,

low score means more limitations). A severity item at the

start of a questionnaire may influence the scoring of dys-

phagia impact domains; for validity it may be important to

clarify how judgments of HRQoL are made when consid-

ering severity of impact first. In the DHI0, correlations

between self-reported clinical severity, total and domain

scores, and a gold standard (VFS) were calculated in an

attempt to arrive at an overall judgment of dysphagia

impact based on a triangulation of clinical and individual

measures, which is especially relevant when using short

measures [51]. HRQoL questionnaires need to be able to

assess both between-subject (reproducibility) and within-

subject (responsiveness) differences for purposes of dis-

crimination and evaluation, respectively [19, 52]. In this

study reproducibility was assessed by both stability over

time within patients (agreement) and the extent to which

patients can be distinguished from each other despite

measurement errors (reliability). As only the MDADI

received a positive rating for agreement and the DHI0 for

reliability, it cannot be assumed that the questionnaires are

appropriate for the assessment of between-subject variation

because of their indeterminate ratings or lack of informa-

tion. If within-person variability in otherwise stable sub-

jects is large, the questionnaire may be unresponsive to real

changes over time, something that has not been assessed

(Table 7) [19, 52]. For these questionnaires to be useful for

discrimination or evaluation, these psychometric properties

need to be evaluated first in future studies.

Emergent Issues When Choosing a HRQoL

Questionnaire: Classification vs. Individualized Use,

Generic or Disease-specific Measures, and Response

Shift

Several quality criteria are important for the clinical

applicability of questionnaires: determining whether the

patient group was involved in defining relevant content

(face validity), determining whether an appropriate clinical

gold standard for experienced distress and disability was

used (criterion validity), and determining the differentia-

tion between relevant subgroups of patients enabling

comparison (interpretability) [53]. The SWAL-QOL has

the strongest ratings for all three criteria; the DHI0 is sec-

ond, supporting the application of the questionnaire with

individual patients. HRQoL is a highly dynamic construct

A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia 195

123

based on personal values and changes in response to illness

[9]. Oropharyngeal dysphagia affects broader aspects of a

patient’s life, such as self-esteem, social contacts, and daily

functioning, and information about these aspects may

influence treatment decisions and assessment of health-care

needs (e.g., quality of survival) [12, 17, 18, 54].

Improvement of symptoms and functional capacity are

usually the main goals of patients seeking care and an

inclination to avoid states that are aversive or bad, such as

pain or physical incapacitation [21, 55]. It has been

increasingly recognized that HRQoL questionnaires can be

used to supplement more objective clinical or biological

measures of disease [50, 56]. Disease-specific measures are

appropriate for assessing dysphagia impact because of the

possibility of detecting relatively small clinically mean-

ingful differences, which are easier to interpret compared

to results of more generic measures such as the Sickness

Impact Profile or the MOS-SF-36 [4, 20, 57]. All patients

included in the studies in this review suffered from oro-

pharyngeal dysphagia, which resulted from cancer in the

upper or lower aerodigestive tract or a neurological con-

dition (see Tables 3, 4). This is important for assessing the

clinically appropriate constructs that really do matter to

patients. However, HRQoL judgments may be influenced

by variables other than the domains included in question-

naires, such as personal coping styles or traits and experi-

enced social support [4, 19]. Ferrans [9] reviewed evidence

on the value of QoL instruments in symptom management

trials. It was found that overall QoL may improve in a

progression-free (i.e., not recovering) group with cancer,

while it declines for a disease progression group, so that

changes in overall QoL were as large or larger than

changes in symptoms of pain, fatigue, insomnia, and

dyspnea [9, 58]. Such outcomes highlight the so-called

‘‘disability paradox,’’ which implies that patients change

their internal standards, values, or concept of QoL during a

period with disease and therefore assess it differently.

Especially in patients with chronic and life-threatening

diseases, changes in HRQoL may result in part from

adaptation to their situation, with existential, spiritual, and

social issues becoming more important [56]. This phe-

nomenon of adaptation has been called response shift:

individuals assess their HRQoL by comparing their

expectations with their experience. Current measures do

not take account of expectations and cannot distinguish

between changes in experience with the disease and in

expectations of health. Most HRQoL measures evaluate the

impact of disease or treatment, not the adaptation of the

patient. Several issues need to be taken into consideration

when using HRQoL measures in clinical settings: (1)

Expectations of health may differ between patients; (2) the

magnitude of disease impact may differ depending on

when the assessment is made in the disease trajectory; and

(3) HRQoL is a dynamic construct that changes over time,

e.g., in response to disease [54]. The evaluation of HRQoL

is of prime importance in chronic or life-threatening dis-

eases due to the focus on reducing the impact of the dis-

ease, which may often be the case in oropharyngeal

dysphagia. The impact of disease may be minimized by

helping patients adjust expectations and adapt to their

changed health status and functioning. From this perspec-

tive, HRQoL may be reflecting the discrepancy between

expectations and experience in patients, which raises pos-

sibilities for health education and counselling. The contents

of HRQoL measures need to be sufficiently broad and use

direct weighting systems, resulting in individualized mea-

sures. All questionnaires for dysphagia impact included in

this study used a scoring system that offered an equal

numerical value to each item before summing the scores

into an overall judgment. This reflects an individual

weighting of domains, which ideally needs to be combined

with a short interview with the patient comparing indi-

vidual impact with more objective clinical measures [50].

It enables physician and patient to determine which scores

are clinically important, as clinical decisions cannot be

made based only on statistically significant differences

with clinical standards [48]. The meaning of differences in

scores varies according to the particular scale, setting

(therapy, disease), and perspective (patient, physician).

However, brevity, ease of administration, and clinically

useful data are essential prerequisites for a measure to be

accepted by physicians [5]. In order for a questionnaire to

be useful in clinical situations, it is important that the

specific purpose, setting of application, and intended pop-

ulation are clearly defined. This is the case for all the

questionnaires used in this study, and when balancing this

with the rated psychometric properties, it seems that the

DHI0 is the most suitable for clinical purposes, given the 25

items and the use of a uniform simple scoring format, in

spite of a negative rating for content validity.

It is necessary to combine psychometric and utility

approaches for all applications of questionnaires for oropha-

ryngeal dysphagia impact and to further strengthen the empir-

ical evidence for selection of measures in the future. This is

possible through head-to-head comparisons of measures within

the same studies as this information would greatly increase

precision and justify the use of a particular questionnaire. A

better understanding of the differences in what HRQoL ques-

tionnaires measure and a sounder base for the assessed effec-

tiveness of clinical interventions will be the result.

References

1. Fries JF. Aging, natural death, and the compression of morbidity.

N Engl J Med. 1980;303:130–5.

196 A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia

123

2. Katz S. The science of quality of life. J Chronic Dis. 1987;

40:459–63.

3. International Health Conference. Constitution of the World Health

Organization. 1946. Bull World Health Organ. 2002;80:983–4.

4. Ware JE. The status of health assessment. Annu Rev Public

Health. 1994;16:327–54.

5. Higginson IJ, Carr AJ. Using quality of life measures in the

clinical setting. BMJ. 2001;322:1297–300.

6. Wilson IB, Cleary PD. Linking clinical variables with health-

related quality of life: a conceptual model of patient outcomes.

JAMA. 1995;273:59–65.

7. Smith KW, Avis NE, Assmann SF. Distinguishing between

quality of life and health status in quality of life research: a meta-

analysis. Qual Life Res. 1999;8:447–59.

8. Ferrans C, Zerwic J, Wilbur J, Larson J. Conceptual model of

health-related quality of life. J Nurs Scholarsh. 2005;37:336–42.

9. Ferrans CE. Differences in what quality-of-life instruments

measure. J Natl Cancer Inst Monogr. 2007;37:22–6.

10. Cook IJ, Kahrillas PJ. Technical review on management of oro-

pharyngeal dysphagia. Gastroenterology. 1999;116:445–58.

11. Garcia-Peris P, Paron L, Velasco C, de la Cuerda C, Camblor M,

Breton I, Herencia H, Verdaguer J, Navarro C, Clave P. Long-

term prevalence of oropharyngeal dysphagia in head and neck

cancer patients: impact on quality of life. Clin Nutr. 2007;26:

710–7.

12. Ekberg O, Hamdy S, Woisard V, Wuttge-Hannig A, Ortega P.

Social and psychological burden of dysphagia: its impact on

diagnosis and treatment. Dysphagia. 2002;17:139–46.

13. Crary M, Groher ME, editors. Introduction to adult swallowing

disorders. Waltham: Elsevier; 2003.

14. Murry T, Carrau RL, editors. Clinical management of swallowing

disorders. San Diego: Plural; 2006.

15. Nguyen NP, Frank C, Moltz CC, et al. Impact of dysphagia on

quality of life after treatment of head and neck cancer. Int J

Radiat Oncol Biol Phys. 2005;61:772–8.

16. Campbell BH, Spinelli K, Marbella AM, et al. Aspiration, weight

loss and quality of life in head and neck cancer survivors. Arch

Otolaryngol Head Neck Surg. 2004;130:1100–3.

17. Gustafsson B, Tibbling L. Dysphagia, an unrecognized handicap.

Dysphagia. 1991;6:193–9.

18. McHorney CA, Martin-Harris B, Robbins J, Rosenbek J. Clinical

validity of the SWAL-QOL and SWAL-CARE outcome tools

with respect to bolus flow measures. Dysphagia. 2006;3:141–8.

19. Spertus JA. Evolving applications for patient-centered health

status measures. Circulation. 2008;118:2103–10.

20. Patrick DL, Deyo RA. Generic and disease-specific measures in

assessing health status and quality of life. Med Care. 1989;27:

S217–32.

21. Feinstein AR. Benefits and obstacles for development of health

status assessment measures in clinical settings. Med Care. 1992;

30:MS50–6.

22. Guyatt GH, Feeny DH, Patrick DL. Measuring health-related

quality of life. Ann Intern Med. 1993;118:622–9.

23. Terwee CB, Bot SD, de Boer MR, Windt DA, van der Knol DL,

Dekker J, Bouter LM, de Vet HC. Quality criteria were proposed

for measurement properties of health status questionnaires. J Clin

Epidemiol. 2007;60:34–42.

24. Timmerman AA, Meesters CM, Speyer R, Anteunis LJ. Psy-

chometric qualities of questionnaires for the assessment of otitis

media impact. Clin Otolaryngol. 2007;32:429–39.

25. Hassan SJ, Weymuller EA Jr. Assessment of quality of life in

head and neck cancer patients. Head Neck. 1993;15:485–96.

26. Terrell JE, Nanavati KA, Esclamado RM, Bishop JK, Bradford

CR, Wolf GT. Head and neck cancer-specific quality of life. Arch

Otolaryngol Head Neck Surg. 1997;123:1125–32.

27. Blazeby JM, Conroy T, Hammerlid E, Fayers P, Sezer O, Koller M,

Arraras J, Bottomley A, Vickery CW, Etienne PL, Alderson D.

Clinical and psychometric validation of an EORTC questionnaire

module, the EORTC QLQ-OES18, to assess quality of life in

patients with oesophageal cancer. Eur J Cancer. 2003;39:1384–94.

28. Cella DF, Tulsky DS, Gray G, Sarafian B, Linn E, Bonomi A,

Silberman M, Yellen SB, Winicour P, Brannon J, Eckberg K,

Lloyd S, Purl S, Blendowski C, Goodman M, Barnicle M, Stewart

I, McHale M, Bonomi P, Kaplan E, Taylor S IV, Thomas CR Jr,

Harris J. The functional assessment of cancer therapy scale:

development and validation of the general measure. J Clin Oncol.

1993;11:570–9.

29. Wallace KL, Middleton S, Cook IJ. Development and validation

of a self-report symptom inventory to assess the severity of oral-

pharyngeal dysphagia. Gastroenterology. 2000;118:678–87.

30. Klugman TM, Ross E. Perceptions of the impact of speech,

language, swallowing and hearing difficulties on quality of life of

a group of South African persons with multiple sclerosis. Fol

Phoniatr Logop. 2002;54:201–21.

31. McHorney CA, Bricker DE, Kramer AE, Rosenbek JC, Robbins J,

Chignell KA, Logemann JA, Clarke C. The SWAL-QOL outcomes

tool for oropharyngeal dysphagia in adults: I conceptual foundation

and item development. Dysphagia. 2000;15:115–21.

32. McHorney CA, Bricker DE, Robbins J, Kramer AE, Rosenbek

JC, Chignell KA. The SWAL-QOL outcomes tool for oropha-

ryngeal dysphagia in adults: II item reduction and preliminary

scaling. Dysphagia. 2000;15:122–33.

33. McHorney CA, Robbins J, Lomax K, Rosenbek JC, Chignell K,

Kramer AE, Bricker DE. The SWAL-QOL and SWAL-CARE

outcomes tool for oropharyngeal dysphagia in adults: III docu-

mentation of reliability and validity. Dysphagia. 2002;17:97–114.

34. Chen AY, Frankowski R, Bishop-Leone J, Hebert T, Leyk S, Le-

win J, Goepfert H. The development and validation of a dysphagia-

specific quality-of-life questionnaire for patients with head and

neck cancer. Arch Otolaryngol Head Neck Surg. 2001;127:870–6.

35. Woisard V, Andrieux MP, Puech M. Validation of a self-

assessment questionnaire for swallowing disorders (deglutition

handicap index). Rev Laryngol Otol Rhinol. 2006;127:315–25.

36. Silbergleit AK, Schultz L, Jacobson BH, Beardsley T, Johnson

AF. The dysphagia handicap index: development and validation.

Dysphagia. 2012;27:46–52.

37. Aaronson NK, Ahmedzai S, Bergman B, Bullinger M, Cull A,

Duez NJ, Filiberti A, Flechtner H, Fleishman SB, de Haes JC.

The European organization for research and treatment of cancer

QLQ-C30: a quality-of-life instrument for use in international

trials in oncology. J Natl Cancer Inst. 1993;85:365–76.

38. Vickery CW, Blazeby JM, Conroy T, Arraras J, Sezer O, Koller

M, Rosemeyer D, Johnson CD, Alderson D. Development of an

EORTC disease-specific quality of life module for use in patients

with gastric cancer. Eur J Cancer. 2001;37:966–71.

39. Blazeby JM, Conroy T, Bottomley A, Vickery C, Arraras J, Sezer

O, Moore J, Koller M, Turhal NS, Stuart R, van Cutsem E,

D’haese S, Coens C. European organisation for research and

treatment of cancer Gastrointestinal and quality of life groups.

Clinical and psychometric validation of a questionnaire module,

the EORTC QLQ-STO 22, to assess quality of life in patients

with gastric cancer. Eur J Cancer. 2004;40:2260–8.

40. Lagergren P, Fayers P, Conroy T, Stein HJ, Sezer O, Hardwick R,

Hammerlid E, Bottomley A, van Cutsem E, Blazeby JM. Clinical

and psychometric validation of a questionnaire module, the EO-

RTC QLQ-OG25, to assess health-related quality of life in

patients with cancer of the oesophagus, the oesophago-gastric

junction and the stomach. Eur J Cancer. 2007;43:2066–73.

41. Bjordal K, Ahlner-Elmqvist M, Tollesson E, Jensen AB, Razavi

D, Maher EJ, Kaasa S. Development of a European organisation

A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia 197

123

for research and treatment of cancer (EORTC) questionnaire

module to be used in quality of life assessments in head and neck

cancer patients. Acta Oncol. 1994;33:879–85.

42. Bjordal K, Hammerlid E, Ahlner-Elmqvist M, Graeff A, de

Boysen M, Evensen JF, Bjorklund A, de Leeuw RJ, Fayers PM,

Jannert M, Westin T, Kaasa S. Quality of life in head and neck

cancer patients: validation of the European organisation for

research and Treatment of cancer quality of life questionnaire-

H&N35. J Clin Oncol. 1999;17:1008–19.

43. Jamoulle M. Traduction Francaise des COOP/WONCA charts

(French adaptation of the COOP/WONCA charts). Brussels:

FMMCSF; 1992.

44. Jamoulle M, Roland M, Blanc HW. Mesure de l’etat fonctionnel

en medecine generale: les cartes COOP/WONCA (Functional

measure in general medicine: the COOP/WONCA charts). Rev

Med Brux. 1994;15:329–32.

45. Stewart AL, Hays RD, Ware JE. The MOS short-form general

health survey: reliability and validity in a patient population. Med

Care. 1988;26:724–35.

46. Ware JE, Sherbourne CD. The MOS 36-item short-form health

survey (SF-36): I. Conceptual framework and item selection. Med

Care. 1992;30:473–83.

47. Brenner MH, Curbow B, Legro M. The proximal distal contin-

uum in multiple health outcome measures: the case of cataract

surgery. Med Care. 1995;33:AS236–44.

48. Wright JG. Interpreting Health-Related Quality of Life Scores -

The simple rule of seven may not be so simple. Med Care.

2003;5:597–8.

49. Gotay CC, Korn EL, McCabe MS, Moore TD, Cheson BD.

Quality-of-life assessment in cancer treatment protocols: research

issues in protocol development. J Natl Cancer Inst. 1992;84:

575–9.

50. Carr AJ, Higginson IJ. Are quality of life measures patient cen-

tred? BMJ. 2001;322:1357–60.

51. Bech P. Quality of life measurement in the medical setting. Eur J

Psychiatry. 1995;10:83s–5s.

52. Guyatt GH, Kirshner B, Jaeschke R. Measuring health status:

what are the necessary measurement properties? J Clin Epidem-

iol. 1992;45:1341–5.

53. Thier SO. Forces motivating the use of health status assessment

measures in clinical settings and related clinical research. Med

Care. 1992;30:MS15–22.

54. Carr AJ, Gibson B, Robinson PG. Is quality of life determined by

expectations or experience? BMJ. 2001;322:1240–3.

55. Faden R, Leplege A. Assessing quality of life - Moral implica-

tions for clinical practice. Med Care. 1992;30:MS166–75.

56. Addington-Hall J, Kalra L. Who should measure quality of life?

BMJ. 2001;322:1417–20.

57. Hays RD, Woolley JM. The concept of clinically meaningful

difference in health-related quality-of-life research—how mean-

ingful is it? Pharmaeconomics. 2000;18:419–23.

58. Osaba D, Brada M, Yung W, Prados M. Health-related quality of

life in patients with anaplastic astrocytoma during treatment with

temozolomide. Eur J Cancer. 2000;36:1788–95.

Angelique A. Timmerman PhD

Renee Speyer PhD

Bas J. Heijnen MSc, SLP

Iris R. Klijn-Zwijnenberg MD

198 A. A. Timmerman et al.: HRQoL Questionnaires in Oropharyngeal Dysphagia

123