Brain (1998),121,1721–1734

Writing disorders in Italian aphasic patientsA multiple single-case study of dysgraphia in a language withshallow orthography

Claudio Luzzatti,1,2 Marcella Laiacona,3 Nadia Allamano,3 Antonio De Tanti4 andMaria Grazia Inzaghi4

1Istituto di Psicologia della Facolta` Medica, Universita` Correspondence to: Claudio Luzzatti, Istituto di Psicologiadegli Studi di Milano,2Servizio di Logopedia, IRCCS della Facolta` Medica, Universita` degli Studi di Milano,Fondazione S. Maugeri, Centro Medico di Montescano, Via Tommaso Pini 1, 20134 Milano, Italy.Pavia, 3Servizio di Neuropsicologia, Divisione di E-mail: luzz@imiucca.csi.unimi.itNeurologia, IRCCS Fondazione S. Maugeri, Centro Medicodi Veruno, Novara,4Unita di Neuropsicologia, Divisione diMedicina Riabilitativa, Ospedale Valduce, Costa Masnaga,Lecco, Italy

SummaryWe report results of a writing task given to 53 mildly tomoderately aphasic Italian subjects. The task wasdesigned to test the writing performance along thesubword-level routine for the spelling of regular wordsand non-words, and along the lexical routine for thespelling of irregular words. The aim of the study was toidentify the incidence of different dysgraphic subtypes inItalian, a language that is considered to have shalloworthography. Its spelling, however, is not completely freeof ambiguity. A five-part writing task was used: (i) wordswith regular one-sound-to-one-grapheme conversion; (ii)words with regular syllabic conversion; (iii) words withambiguous transcription; (iv) loan-words; and (v) non-words. For regular words, the effects of word length andword frequency, and of the variables determining thecomplexity of the acoustic-to-phonological conversion(continuant versus plosive phones; consonant-vowelsequence versus doubled consonants or consonant

Keywords: dysgraphia; aphasia; writing; stroke

IntroductionOver the past two decades cognitive psychologists haveproposed increasingly complex models to describe theprocesses underlying the normal processing of writtenlanguage. These models were originally formulated todescribe the operations underlying word naming (Coltheartet al., 1980; Pattersonet al., 1985) and were subsequentlyadapted to describe writing of words to dictation (Beauvoisand Derouesne´, 1981; Shallice, 1981; Baxter and Warrington,1985; Harris and Coltheart, 1986; Patterson, 1986). Themodels assume the need for at least two processing routes,

© Oxford University Press 1998

clusters) were also considered. Patients’ performanceswere classified according to the presence of a dissociationbetween (i) regular words and non-words, (ii) regularwords and words with unpredictable spellings, and (iii)one-to-one and syllabic conversions. The 53 aphasicpatients span the whole spectrum of dysgraphic taxonomy.Thirty-nine patients, in particular, manifested adissociated pattern of performance. Eighteen patientsshowed a prevalent surface dysgraphic pattern and sevena phonological one, while 11 patients showed a mixedpattern (i.e. a better performance for regular wordsthan for ambiguous words or regular non-words). Threepatients showed a specific deficit for regular syllabicconversion rules only. A high rate of ‘mixed dysgraphia’suggests either a mutual interaction of the two impairedroutines when regular words are written, or two separatefunctional lesions: one at the level of the auditory-to-phonological conversion procedure, the other at the levelof the orthographic output lexicon.

a lexical routine by which words are processed as a whole,and a subword-level routine following orthographic-to-phonological conversion rules in reading, and vice versa,phonological-to-orthographic conversion rules in writing. Theneed for at least two procedures was formulated for Englishto explain the capacity of a literate subject to read and writeboth irregular words and legal non-words (i.e. non-lexicalbut phonotactically plausible phonological strings).

Two routines are assumed to be necessary for readingaloud and writing to dictation in English, given that English

1722 C. Luzzattiet al.

is a language with a relatively irregular orthographic system.On account of this irregularity it is often impossible to deducethe spelling of a word from the sequence of sounds thatmake it up. The claim for two routines has also been arguedon the basis of results from patients with cerebral lesions.Focal brain damage may cause writing disorders that appearto involve either routine selectively. Consequently, somepatients make correct use of phonological-to-orthographicconversion rules when writing, but cannot access lexicalknowledge, and therefore regularize the spelling of irregularwords. Such a deficit is generally called ‘surface dysgraphia’.Other patients can write words they have learned to spell inthe past, whether these be regular or irregular, but are notable to write a legal non-word. Such a disturbance is generallycalled ‘phonological dysgraphia’.

[N.B. We did not consider the possible further fractionatingof the lexical routine into a semantic lexical and a directphonological/orthographic lexical routine in this study.Consequently, the possibility of a writing deficit correspond-ing to the isolated impairment of these subroutines (directdysgraphia) could not be tested.]

Not all languages with an alphabetical system of writingare irregular like English. Some languages, such as Serbo-Croatian, are almost totally predictable, with regard to bothreading and writing. Others may be relatively regular in onedirection but not in the other; this is the case with Frenchand German, the writing of which is very often unpredictablebut reading aloud is relatively predictable. Italian is said tobe a language with a shallow orthography, where the subword-level routine is sufficient for the great majority of words tobe written. The phonological-to-orthographic conversion rulesare simple with a one-to-one correspondence between soundand letter for all vowels and most consonants. As is the casewith the majority of European languages, some Italian phonesdo not correspond to a single letter of the alphabet. Thetranscription of these phones is generally achieved by twoor more letters. Typical examples are the phones [Q] (5 TH

of English), [X] (5 CH of German), or the different spellingof [S] in Italian (SC6I), French (CH), English (SH) and German(SCH). The most typical Italian phones without a one-to-onecorrespondence are [ˆ] and [¥]; these are conveyed by theletter-pairsGN and GL, respectively. Slightly different is therealization of the velar versus palatal pairs [k] – [tS] and [g] –[dJ]. In the first case the rule is relatively simple—one mustconvert a phoneme with several letters instead of one. Inthe second case a syllabic conversion is required, i.e. theorthographic realization of a phone is determined by thevowel that follows it ([ka], [ko], [ku] 5 CA, CO, CU; [ki], [ke] 5CHI, CHE; [tSa], [tSo], [tSu] 5 CIA, CIO, CIU; and [tSi], [tSe] 5CI, CE).

Finally, there are also conditions in Italian that areunpredictable both in written-to-oral and oral-to-writtendirection. Ambiguities in reading concern the site of stressin words of three or more syllables (GONDOLA (5 gondola)is pronounced [9gondola] and not *[gon9dola], whereasMENTOLO (5 menthol) is stressed [men9tolo] and not

*[ 9mentolo]). On the other hand, there are some conditions inwhich a given phonological string has more than one possibleorthographic solution, though only one is correct for a certainlexeme; ambiguities in writing often have an etymologicalbasis, and may apply to the pronunciation of some linguisticareas only.

(i) The syllable [Se], for instance, is regularly transcribedby the sequenceSCE. However, there are some words inwhich it is conveyed by the sequenceSCIE, e.g. [Sentsa] 5SCIENZA (5 science). The same applies to the syllables [tSe]and [dJe] which in certain cases are transcribed by thesequenceCIE andGIE (CIELO (5 sky) instead ofCELO, IGIENE

(5 hygiene) instead ofIGENE).(ii) The phonemic group [kw] may be transcribed by the

orthographic sequencesQU, CU, CQU. The general rule is thatthe syllables [kwa], [kwi] and [kwe] are transcribed with thesequencesQUA, QUI andQUE, e.g.QUALE (5 which), QUINDI (5thus), QUESTO (5 this), while the syllable [kwo] is transcribedby the sequenceCUO [CUOCO (5 the cook)]. However,exceptions exist here too, e.g.QUOTA (5 the quota).

(iii) The segments [¥] – [lj] and [ ] – [nj] which arephonologically distinct in Tuscan and central-southernpronunciation, are homophones in north-western Italian, somuch so that the spelling of words likebalia [ba¥a]/[balja],nurse (BALIA and notBAGLIA ) or geranio[dJeraˆo]/[dJeranjo],the geranium (GERANIO and notGERAGNO) is not predictablealong the phonological-to-orthographic conversion routine.

(iv) Plosive phones that are followed by the liquidconsonants ([l] and [r] or by the semiconsonant [j] arehomophones to their doubled pairs, thus rendering uncertainthe transcription of words such as [libro], book (LIBRO andnot LIBBRO), [febre], fever (FEBBRE and notFEBRE), [biblico],biblical (BIBLICO and not BIBBLICO) and [publico], public,(PUBBLICO and notPUBLICO).

(v) Finally, mention should be made of the spelling of‘loan-words’ (usually from English or French) incorporatedinto the Italian lexicon (e.g.BLUE-JEANS, WEEK END,etc.).

A correct use of the subword-level routine (i.e. of thephonological-to-orthographic conversion rules) requires thatthe subject first segments and identifies the phonemic stringto be converted. Such analysis seems to be adequatelyrepresented by the information processing models in theacoustic-to-phonological conversion. This is the routinedescribed by Wernicke (1885, 1886), who considered theprocessing of written language as exclusively segmental, asopposed to a purely lexical routine for the processing of orallanguage (De Bleser and Luzzatti, 1989).

An acoustic-to-phonological level of analysis obviouslydepends on variables determining the complexity of thisprocessing, such as the presence of consonant clusters,or the phonetic characteristics of the sounds themselves.Continuous phones, such as vowels, fricative consonants ([f],[v], [s], [z] and [S]), liquid ([ l] and ([n]), and nasal ([n] and[m]) consonants that may be prolonged during the analysis,are by their nature more easily segmentable and hence

Diagnosis of writing disorders 1723

identifiable, as it is possible to analyse their audio-phonetic(and stato-kinaesthetic) aspects at greater length.

In order to evaluate the variables individually, describedso far, a test battery was designed for the examination ofwriting disturbances in adult brain-damaged subjects. Certainphonetic/phonological variables generally overlooked inpsycholinguistic studies were added to the variables generallyconsidered in normal test batteries for writing deficits (lengthof stimulus, lexical/non-lexical material, word frequency).

Material and methodsSubjectsFifty-three mildly to moderately aphasic patients (30 malesand 23 females) examined at the Aphasia Units of Rho-Passirana (Milano), Veruno (Novara) and Costa Masnaga(Lecco) from 1993 to 1994 were included in the study. Theirmean (6 SD) age was 41.96 17.9 years and education10.86 2.5 years; their mean length of illness was 13.26 18.3months. Forty patients suffered from vascular cerebraldamage, 11 from traumatic brain injury and two from otheraetiologies. Type and severity of aphasia was assessed bymeans of the Italian version of the Aachen Aphasia Test(Luzzattiet al., 1994a): 14 patients were classified as Broca’saphasics, 21 had a fluent language disorder (11 Wernicke’s,six anomic and four non-classifiable aphasic patients). Eightpatients could not be classified for the fluent/non-fluentdimension, whereas 10 showed only minimal residuallanguage deficits. The control group included 110 healthyadults (49 males and 61 females). Their mean age was 44.26 15.1 years. Only subjects withù8 years of schoolingwere included in order to be assured of a complete acquisitionof written language (mean education 13.16 3.7 years).Subjects gave informed consent to participate in the study,which had ethical approval from the S. Maugeni Foundation.

The testThe writing test used in this study is described fully in Luzzattiet al. (1994b). It comprises the following five sections.

Section A uses regular words with complete one-sound-to-one-letter correspondence.

Section B uses regular words with syllabic conversion(e.g. [k], [g], [tS], [dJ]). The spelling of sounds [¥], [ˆ], andsyllables [tSe], [dJe] and [Se] which have two possibleorthographic solutions (see next point) was not taken intoaccount in this section.

Section C uses words with unpredictable transcriptionalong the phonological-to-orthographic conversion routine(e.g. [¥] in [pa¥a], straw:PAGLIA and notPALIA ; [ba¥a], nurse:BALIA and notBAGLIA , or [ˆ] in [dJeˆo], genius:GENIO andnot GEGNO; [seˆo], sign: SEGNO and notSENIO).

Section D uses loan-words: foreign words which may bynow be considered as part of the Italian lexicon (e.g. blue-jeans, night-club).

Section E uses non-words with one-sound-to-one-lettercorrespondence.

As the experimental subjects were natives of Lombardyand Piedmont, in addition to the ambiguities which arecommon to all Italian speaking areas (e.g. the spelling of thesyllable [kwo] or the single/doubled orthographic pair in aplosive followed by a liquid consonant), some of theambiguities which are typical of the north-western Italianpronunciation were included.

Moreover, in order to evaluate different sources ofphonetic-phonological complexity, within Section A thefollowing comparisons were made: (i) words made up onlyof continuant sounds (fricative, liquid or nasal consonants)with words also containing non-continuant (plosive)consonants; (ii) words made up only of consonant-vowel(CV) syllables with words also containing clusters or doubledconsonants; (iii) bisyllabic with polysyllabic words. Eachpart of Section A used five high-frequency and five low-frequency words (Bortoliniet al., 1972). Table 1 summarizesthe different sections of the writing task (see Appendix forthe complete list of stimuli).

The mean word frequency for each section is shownin Table 2. Regular words and words with unpredictabletranscription have a very similar frequency, whereas loan-words are less frequent. The mean word frequencies of thefive high-frequency and five low-frequency items for SectionA (regular words with complete one-sound-to-one-lettercorrespondence) are also shown.

Items are almost exclusively nouns; therefore the task doesnot enable us to detect word class differences. Furthermore,the task does not consider any lexical-semantic variables(such as the abstract/concrete dimension) that have beenshown to influence the performance along the lexical routine(Bub and Kertesz, 1982; see also Shallice, 1988, pp. 138–142).

Words and non-words were presented separately. The 158words were randomized for regularity, complexity, wordfrequency and length, the 25 non-words for complexity andlength. The examiner read each item aloud in a neutral tone,i.e. without emphasizing the presence of clusters, doubledconsonants or possible orthographic ambiguities. Each itemcould be repeated once on request. No feedback was providedon the adequacy of the responses. Spontaneous correctionswere accepted.

Analyses of the results and statistical methodsAll the patients participating in the study suffered from aleft hemisphere lesion causing mild-to-moderate languagedisorders and/or dysgraphia, but none showed a pure writingdisorder. The principal purpose of our investigation was todetect the presence of significant differences between theability to spell regular words, words with unpredictabletranscription and non-words separately. The diagnostic criteriafor different types of dysgraphia concern the dissociated(independent) impairment of performance with these differentsets of stimuli. Since the majority of the patients showed

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Table 1 Subtests of the writing taskA Regular words with one-sound to one-letter correspondence (n 5 80)

Examples (Translation) Continuance Clusters Doubled Syllables nconsonants

1 sole (sun) Yes No No 2 102 lavoro (work) Yes No No 3/4 103 senso (sense) Yes Yes No 2 104 valle (valley) Yes No Yes 2 105 dito (finger) No No No 2 106 prato (meadow) No Yes No 2 107 tappo (cork) No No Yes 2 108 sponda (bank) No Yes (32) No 2 10

B Regular words (syllabic conversion rules) (n 5 15)

Example Rule n

9 gola/ghiro/valigia [k], [g], [sk]; [ tS], [dJ], [S] 15(throat/dormouse/suitcase)

C Words with unpredictable transcription (n 5 55)

Examples (translation) Ambiguity n

10 scena/scienza (scene/science) [tS], [S] : 6 I 1011 paglia/balia (straw/nurse) [¥] : GL/LI 1012 segno/genio (sign/genius) [] : GN/NI 1013 libro/febbre (book/fever) BR/BBR 1014 cuore/quota/aquila (heart/quote/eagle) [kw] : CU/QU 15

D Loan-words (n 5 8)

Examples n

15 blue-jeans, night-club 8

E Non-words with one-sound-to-one-letter correspondence (n 5 25)

Examples Continuance Doubled Syllables nconsonants

1 nise Yes No 2 52 vimane/ramasola Yes No 3/4 54 seffa Yes Yes 2 54 tido No No 2 55 nitta No Yes 2 5

Table 2 Word frequencies in the different tasks

Stimulus Word frequency (mean6 SD)

Regular words (one-sound-to-one-letter correspondence) 47.396 69.57high frequency items 91.256 76.42low frequency items 3.526 4.33

Regular words (syllabic conversion) 31.476 40.53

Words with unpredictable transcription 47.556 96.49

Loan-words (,2)

Total 43.536 76.86

Diagnosis of writing disorders 1725

Table 3 Performance of patients and control subjects on the five sections of the writing task (mean6 SD)

Section Control All aphasic Broca’s Wernicke’s Anomic Residualsubjects patients aphasia aphasia aphasia language(n 5 110) (n 5 53) (n 5 14) (n 5 11) (n 5 6) deficits

(n 5 10)

A. Regular words with one-sound-to-one- 79.86 0.6 61.86 19.0 54.96 15.8 50.66 28.7 73.26 8.8 76.66 3.1letter correspondence (n 5 80)

B. Regular words with syllabic 15.06 0.2 9.96 4.1 8.16 3.7 8.26 5.3 11.86 1.9 13.46 1.7conversion (n 5 15)

C. Words with unpredictable transcription 52.56 2.2 29.26 13.6 23.16 13.2 22.86 13.7 35.36 12.9 42.36 7.5(n 5 55)

D. Loan-words (n 5 8) 5.9 6 2.5 1.26 1.8 0.66 1.2 0.36 0.7 2.06 2.1 2.46 2.6

E. Non-words (n 5 25) 24.76 0.6 14.66 8.1 10.56 7.5 13.16 8.8 17.76 5.1 22.46 2.4

mild-to-moderate language disorders, only a few patientsshowed a classical (strong) dissociation between a completelyspared and a damaged writing routine. In fact, thedissociations shown by our patients are usually of the weaktype, i.e. there is usually poor performance on both routines,though one routine is significantly more impaired.

Logistic regression analysis (McCullagh and Nelder, 1983)was applied to the profile of each single subject, making itpossible to study the effects of the variables that might haveinfluenced performance within a linear model. The units werethe stimuli of the Test and the dependent variable for eachstimulus was two-valued (passed5 1, failed 5 0). Themodel included both categorical (e.g. words versus non-words) and continuous variables (word frequency and itemdifficulty). Difficulty (for each single item) is expressed asthe number of control subjects (out of 110) who wroteit correctly. Each patient was classified into one of themajor dysgraphic patterns through several comparisons.First, the four major sections of the task were checked foran overall performance homogeneity. Then, the followingcomparisons were made: (i) words with one-sound-to-one-letter correspondence and non-words with comparablephonological and orthographic complexity; (ii) wordswith unpredictable transcription and words with one-sound-to-one-letter correspondence; and (iii) words with syllabicconversion and words with one-sound-to-one-lettercorrespondence. The eight loan-words were not consideredin the logistic regression analyses as they constitute a separateand very limited set of items. Furthermore, the influence ofthe different sources of complexity included in the test, suchas continuance, stimulus length and the presence of consonantclusters, was evaluated. Comparisons were programmed asa macro-instruction of the Generalized Linear Model programof Aitkin et al. (1989) (GLIM 3.77). The analysis wasrepeated for each of the 53 patients. As a single-casediagnostic procedure was used, the significance level of eachcomparison was set at 0.05, without adopting an overallprotection for the whole set of patients (Willmes, 1985).

The psychometric design also included covariance by itemdifficulty. Any dissociation still present after this adjustmentwill be stronger than—and not simply proportional to—the

difference observed among control subjects. On the contrary,any dissociation which disappears after adjustment simplyreflects the difficulty gradient observed in the normalcontrol group.

ResultsControl subjectsThe mean scores of the 110 control subjects on the fivesections of the test, and on the eight parts of SectionA (writing of regular words with one-sound-to-one-lettercorrespondence), are shown in Tables 3 and 4. Normalsubjects wrote almost all items of the task flawlessly.However, this was not the case for the loan-word section,where control subjects registered a lower mean performanceand a high degree of variability (5.96 2.5). An analysis ofthe performance of the control subjects was reported in detailin a previous paper (Luzzattiet al., 1994b). Educationsignificantly influences the spelling of words withunpredictable orthography, age influences that of non-words,and both education and age influence that of loan-words.None of these variables, however, significantly influencedthe subjects’ performances when they were writing regularwords. An error analysis also revealed that the misspellingsof the control subjects corresponded to those predicted forthe different parts of the writing task. Normal subjects madea very low number of errors when writing regular words andnon-words [for instance, when writing regular words theyonly made 12 errors out of 8800 written words]. The analysiswas therefore made only for words with unpredictabletranscription and for loan-words. Out of 6050 wordscontaining a phone with an unpredictable transcription,control subjects made 435 errors; 378 of these were of theexpected type (use of the subword-level routine instead ofthe lexical one, and therefore substitution of the target witha plausible but incorrect solution). When writing loan-words,control subjects produced 272 errors out of 880 writtenwords; again, 94% of the misspellings were surface errors.

Aphasic patientsTable 3 also shows the mean performances obtained on thefive sections by the 53 aphasic patients and by the 31

1726 C. Luzzattiet al.

Fig. 1 The five sections of the writing test: score profiles (mean percentages) from control subjects and the aphasic patients who couldbe classified into one of the major aphasic syndromes.

Table 4 Performance on the eight parts of Section A (regular words with one-sound-to-one-letter correspondences)*

Section A Control All aphasic Broca’s Wernicke’s Anomic Residual(parts 1–8) subjects patients aphasia aphasia aphasia language

(n 5 110) (n 5 53) (n 5 14) (n 5 11) (n 5 6) deficits(n 5 10)

1 (e.g.sole, sun) 9.976 0.2 8.66 2.3 8.06 2.5 8.26 3.3 9.76 0.8 9.86 0.42 (e.g.lavoro, work) 9.976 0.2 6.96 3.3 5.96 3.1 5.36 4.3 9.06 1.1 9.36 0.83 (e.g.senso, sense) 9.956 0.3 7.46 3.0 6.26 2.6 5.96 4.4 9.56 0.8 9.46 0.84 (e.g.valle, valley) 9.976 0.2 8.26 2.4 7.46 2.3 6.76 3.6 9.36 1.0 9.66 0.75 (e.g.dito, finger) 9.976 0.2 7.96 2.6 7.66 2.4 6.56 3.6 8.86 1.6 9.96 0.36 (e.g.prato, meadow) 10.006 0.0 7.76 2.7 6.86 2.7 5.96 3.7 9.26 1.3 9.56 0.77 (e.g.tappo, cork) 9.976 0.2 8.56 2.3 8.16 1.8 6.96 3.8 9.36 0.8 9.86 0.48 (e.g.sponda, bank) 9.996 0.1 6.66 3.1 4.96 3.1 5.56 3.9 8.36 2.3 9.36 1.1

Data are shown as means6 SD. *See Table 1, Section A for the eight types of words.

patients whose quantitative and qualitative performancescorresponded to that of a classic Broca’s (n 5 14), Wernicke’s(n 5 11) and anomic (n 5 6) aphasia.

Table 4 shows the mean performance on the eight parts ofSection A (writing of regular words with one-sound-to-one-letter correspondence) for all patient groups.

The mean (percentage) score profiles of control subjectsand of the 31 patients that could be grouped according tothe major aphasic syndromes are shown in Figs 1 and 2.

Profiles of each individual subject were analysed by meansof a logistic regression analysis. Due to the high variabilityshown by control subjects with loan-words, the patients’performances in Section D were not considered in theregression analysis. The results are given in Table 5 andsummarized in Table 6.

Eighteen patients (34%) showed predominantly a writing

impairment for words with unpredictable spelling, i.e. wide-spread damage to the lexical routine (surface dysgraphia),while seven patients (13%) showed an impairment for non-words, i.e. mainly damage to the subword-level routine(phonological dysgraphia). Of the 18 surface dysgraphicpatients, only four (MI02, VE08, CM04 and VE12) showedselective impairment of the lexical route and normalperformance with non-words, while only one of the sevenphonological dysgraphic patients (VE07) showed a selectiveimpairment of non-words (subword-level routine) and normalspelling of regular words and of words with unpredictablespelling. Furthermore, 11 subjects (21%) showed a peculiarpattern of damage, characterized by an impaired writingperformance for both words with unpredictable transcriptionand non-words, while they performed better on regular wordswith complete one-sound-to-one-letter correspondence. The

Diagnosis of writing disorders 1727

Fig. 2 The eight parts of Section A of the writing test (regular words with one-sound-to-one-letter correspondence): score profiles fromcontrol subjects and aphasic patients that could be classified into one of the major aphasic syndromes.

term ‘mixed dysgraphia’ will be used to designate the patternof disruption observed in this group of patients. Threepatients (6%) used the one-phoneme-to-one-letter conversionflawlessly but had trouble with syllabic conversion rules.Thirteen patients (25%) presented an undifferentiated writingdeficit on all tasks, whereas one patient (2%) had no writingdisorders. The analysis within the 80 items of Section Ashowed that four patients (8%) performed better on wordscomposed exclusively of continuant phones (and thus moreeasily analysable by the auditory-to-phonological conversionunit) than on words also containing plosive consonants.Furthermore, nine patients (17%) showed a length effect,and the performance of four patients (8%) was influenced bythe presence of consonant clusters. Half of the patients (24out of 53) showed a word-frequency effect. The rate ofpatients showing a word-frequency effect varied across typeof dysgraphia: six out of the seven patients with aphonological dysgraphia (86%), two of the three patientswith a pure syllabic conversion deficit (67%), eight of the18 patients with a surface dysgraphia (44%), six of the 11patients with a mixed dysgraphia (55%) and two of the 13patients with undifferentiated writing disorder showed aword-frequency effect; the patient with no dysgraphia didnot show a word-frequency effect. A comparison of therate of cases showing a word-frequency effect evidenced adifferent distribution between the phonological (6/7) andsurface (8/18) dysgraphic patients (Fisher’s exact test (1),P, 0.05).

Finally, semantic substitutions were limited to only twopatients, and even in these two cases they were few [e.g.CM07: night-club→playboy; weekend→week-fine (Italiantranslation of ’end’); VE02: babbo´→papa9 (father→dad);

bacio→abbracio´ (kiss→hug)]. In both cases the phonological-to-orthographic conversion routine was severely impaired.However, these patients showed a different degree of damagewhen writing words with unpredictable spelling. The firstpatient (VE02) could still write the majority of these words,and was therefore classified as a case of phonologicaldysgraphia, whereas the second patient (CM07) had a moreconspicuous deficit of ambiguous words and was thereforeclassified as a case of mixed dysgraphia, still showing,however, a clear dissociation between ambiguous words andnon-words (42% versus 0%).

Table 6 also shows the distribution of dysgraphic disordersaccording to the classic aphasia taxonomy. Types ofdysgraphia are similarly distributed along aphasic syndromes[χ2(25) 5 15.04, not significant].

Table 7 shows the distribution of patients with dysgraphicdisorders according to aetiology. All seven of the phonologicaldysgraphic patients were found within the vascular group,while surface dysgraphia is proportionally more frequentamong patients suffering from traumatic head injury. Thisdifference, however, does not reach significance [χ2(5) 57.088, not significant].

DiscussionThe purpose of the present study was to verify the diagnosticvalidity of a writing task and the use of logistic regressionanalysis in a psychometric single case analysis. The writingtask was administered to a sample of mildly to moderatelyaphasic Italian patients. The performances of the patientswere compared to those of 110 control subjects (Luzzattiet al., 1994b).

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Table 5 Classification of individual patients with multiple single-case analysis (logistic regression analysis)

Case Words with one-sound to one-letter correspondences versus: Other significant effects:

non-words words with words with continuancy length consonant wordunpredictable syllabic conversion clusters frequencytranscription

χ2 P-value χ2 P-value χ2 P-value

Phonological dysgraphiaCM09 6.524 0.011 0.065 1.299 0.254 . . . 1CM18 15.292 ,0.0001 0.005 1.491 0.222 . . . 1MI08 6.622 0.010 1.619 0.203 1.291 0.256 . 1 . 1VE02 29.898 ,0.0001 0.429 0.512 1.265 0.261 . . . 1VE04 14.329 0.0001 0.558 0.215 . 1 . 1VE07 4.984 0.026 0.132 2.961 0.085 . . .VE18 8.479 0.004 0.034 0.988 . 1 . 1

Deficit of syllabic conversion onlyCM08 0.961 1.567 0.211 4.937 0.026 . . . 1CM10 1.224 0.269 3.302 0.069 6.198 0.013 . . . 1MI14 0.189 0.650 5.555 0.018 . 1 . .

Surface dysgraphiaMI07 0.883 16.680 ,0.0001 10.999 0.0009 . . . .CM05 3.129 0.077 8.624 0.003 6.716 0.010 . . . 1MI02 0.585 15.358 ,0.0001 5.576 0.018 1 . . 1MI12 0.154 11.043 0.0009 8.830 0.003 1 . . .MI15 0.635 12.607 0.0004 5.564 0.018 . . . 1VE08 0 48.720 ,0.0001 8.734 0.003 . . . .MI06 0.285 8.741 0.003 2.423 0.120 . . . .CM02 0.045 21.272 ,0.0001 1.801 0.180 . . . .CM03 0.480 21.683 ,0.0001 1.828 0.176 . . . .CM04 0.975 9.490 0.002 2.944 0.086 . . . 1VE12 0 8.729 0.003 0 . . . .MI03 0.065 9.194 0.002 0.122 . . . 1MI04 0.439 5.333 0.021 0.005 . . . .CM16 1.235 0.266 5.083 0.024 0.761 . . . 1MI10 3.741 0.053 11.174 0.0009 0.464 . . . .VE06 1.282 10.720 0.001 0.246 . . . 1VE13 1.608 0.205 10.060 0.002 0.271 . . 1 .VE16 0.373 9.467 0.002 0.549 . . . 1

Mixed (phonological and surface) dysgraphiaVE03 10.682 0.001 4.932 0.026 3.899 0.048 1 . 1 .CM06 14.675 0.0001 5.201 0.023 3.100 0.078 . . . 1CM07 33.764 ,0.0001 8.290 0.004 0.003 . 1 1 1CM12 12.451 0.0004 7.793 0.005 1.769 0.184 . . . 1CM19 7.326 0.007 12.095 0.0005 2.167 0.141 . . . .MI09 11.652 0.0006 6.082 0.014 0.328 . . . 1MI11 11.395 0.0007 17.841 ,0.0001 0.849 . . . 1VE01 5.150 0.023 27.595 ,0.0001 1.509 0.219 . . . .VE10 4.563 0.033 6.985 0.008 2.677 0.102 . 1 . .VE11 6.174 0.013 13.591 0.0002 0.179 1 . . .VE15 16.264 ,0.0001 4.281 0.039 0.987 . . . 1

Undifferentiated writing disordersCM01 2.092 0.148 3.430 0.064 0.059 . . . .CM11 1.017 0.313 2.039 0.153 3.740 0.053 . . . 1CM13 2.035 0.154 0.670 1.219 0.270 . 1 . .CM14 0.831 3.668 0.055 3.644 0.056 . . . .CM15 0.050 1.827 0.176 0.164 . . . .CM17 0.055 0.389 2.408 0.121 . . . .MI05 0.775 2.302 0.129 0.290 . 1 1 .MI13 0.200 1.212 0.271 0.014 . 1 . .MI16 2.888 0.089 0.041 0.108 . . . .VE05 3.002 0.083 2.005 0.157 1.366 0.243 . . . 1VE09 0.002 1.957 0.162 0.051 . . . .VE14 0.015 2.739 0.098 0.656 . . . .VE17 1.791 0.181 1.897 0.168 2.889 0.089 . . . .

No dysgraphiaMI01 0.164 0.136 0.007 . . . .

χ2 andP-values in bold reflect significant effects.

Diagnosis of writing disorders 1729

Table 6 Type of dysgraphia by type of aphasia: distribution across the 53 aphasic patients

Broca’s Wernicke’s Anomic Fluent aphasia Residual Non-classifiable All patientsaphasia aphasia aphasia (non-classifiable: language (fluent versus (n 5 53)(n 5 14) (n 5 11) (n 5 6) Wernicke’s deficits non-fluent

versus anomic) (n 5 10) aphasia)(n 5 4) (n 5 8)

Phonological 3 2 1 – – 1 7dysgraphia

Deficit of syllabic – 1 – 1 1 – 3conversion

Surface 5 3 3 1 4 2 18dysgraphia

Mixed dysgraphia 3 2 1 1 1 3 11(phonological andsurface)

Undifferentiated 3 3 1 1 3 2 13writing disorders

No dysgraphia – – – – 1 – 1

Table 7 Type of dysgraphia by aetiology: distribution across the 53 aphasic patients

Vascular Traumatic Other Allaetiology aetiology aetiology patients(n 5 40) (n 5 11) (n 5 2) (n 5 53)

Phonological dysgraphia 7 – – 7Deficit of syllabic conversion 3 – – 3Surface dysgraphia 10 6 2 18Mixed dysgraphia (phonological and surface) 10 1 – 11Undifferentiated writing disorders 9 4 – 13No dysgraphia 1 – – 1

Many contemporary models assume the existence of atleast two writing routines, one lexical and one at subword-level. In this framework, the first routine is the only optionpossible when writing words with unpredictable or irregularspelling, the second is the only option when writing non-words. Italian is a language with quite regular spelling, sothat the great majority of words may be written along thesubword-level routine. For this reason, it has often beenclaimed (e.g. Deneset al., 1996) that writing deficits withfeatures of surface dysgraphia (i.e. due to damage of thelexical routine only) should be less frequent among Italianpatients. However, in spite of the overall regularity ofthe Italian orthography, some phones have more than onegraphemic realization, though only one is correct for agiven lexeme.

On the other hand, the efficient use of the subword-levelroutine requires a correct acoustic-to-phonological conversionto allow the isolation of the single phones to be routed tothe phonological-to-orthographic conversion. The relevanceof a phonological analysis level had already been stressedby Luria et al. (1969). These authors suggested that ‘the taskof writing a given word [whether independently or fromdictation] begins with the process of analysis of the phonetic

composition of the word, or in other words, with the breakingdown of the phonetic stream of living speech into isolatedphonemes’. This acoustic-analysis level should depend onthe variables determining the complexity of this process, i.e.the presence of consonant clusters or the phonetic-acousticaspects of the single phones (e.g. plosive versus continuant).

Control subjects from the normative sample (Luzzattiet al.,1994a, b) write all regular words almost perfectly, irrespectiveof either the phonetic-acoustic aspects of the phones, or ofthe presence of consonant clusters or of the type of conversionrules (one-to-one versus syllabic rules). Older subjects mademore errors when writing loan-words which do not followthe regular Italian orthography. This seems to be due simplyto the recent appearance of these items in the Italian lexiconand, therefore, to a lack of acquisition of their orthographyby older subjects. The effect of age on writing non-words is,however, more difficult to explain. On the one hand, it maybe due to a peripheral mechanism by which a loss of hearing,however mild, can lower the performance of writing non-words, due to the lack of lexical feedback. On the other,impaired writing of non-words in ageing could be explainedby the results of Bisiacchiet al. (1989) which demonstratedthat the processing of non-words puts a higher load on the

1730 C. Luzzattiet al.

Fig. 3 Information-processing model of word naming, confrontation naming and writing [from Patterson(1986), modified].

phonological short-term memory, a function that has beenshown to undergo a progressive impairment in ageing (Orsiniet al., 1987; Spinnler and Tognoni, 1987).

Aphasic patients made more errors when writing wordswith unpredictable spelling and non-words. Comparingperformances on the different subtests, aphasic subgroups(Broca’s, Wernicke’s and anomic aphasia) differ in severity,but the profile shape is almost identical. The variablesinfluencing the outcome along the subword-level routinealso show a similar profile of impairment across aphasicsubgroups. Obviously, the classification of patients accordingto aphasic syndromes does not imply that there is anidentical cognitive disorder in all subjects sharing the sameaphasiological label: on the contrary, a similar distributionof dysgraphic subtypes across aphasic syndromes is a proofof the manifold composition within these groups of subjects.Preliminary results from a comparable study of readingdisorders (C. Luzzatti, M. Frustaci, C. Guarnaschelli,M. Taricco, G. Zonca, unpublished results) seem to suggesta different pattern of impairment with respect to dysgraphia;

phonological and deep dyslexic disorders are more frequentlyassociated with agrammatism, while surface dyslexia isassociated with jargon aphasia. It would therefore seem that,in Italian at least, reading and writing undergo a differentbreakdown pattern.

The profiles of the individual patients were analysed witha linear model that included the frequency of each item andits rate of difficulty for the control subjects. The choice ofthis stricter criterion calls for comment. Let us first considerthe case of word frequency. Non-words have, by definition,a frequency value of zero. Confusion between two variablesof the model, i.e. type of items and word frequency, couldtherefore be suggested. As a consequence, adjustment forfrequency could artifactually affect the word/non-worddifference and, therefore, the incidence of phonologicaldysgraphia. Even if this effect is theoretically possible, weassume that the comparison of performances with words andnon-words identifies a difference between processing routinesthat cannot simply be reduced to the effect of the stimulusfrequency. In fact, this possible bias did not reduce the

Diagnosis of writing disorders 1731

rate of dissociated patterns significantly, as the number ofphonologically dysgraphic patients before frequencyadjustment was eight, and after adjustment for frequency andstimulus difficulty it was only reduced to seven. Furthermore,as the items included in the different sets were matched forword frequency, it did not affect the comparisons betweensections of the test.

A further observation concerns the policy of adjusting byitem difficulty, as assessed in control subjects. The aim ofthis adjustment is obviously not to cancel the fact that wordswith unpredictable transcription may be ‘more difficult’ thanregular words, but to test whether the difficulty gradientobserved in the patients was proportional to that observed incontrol subjects. For the above-mentioned reasons we decidedto adopt a stricter criterion for the identification of dissociatedpatterns of dysgraphia, where possible effects of interferenceof the patients’ performances were partialled out by anadjustment of the scores by item difficulty and word-frequency effect.

The multiple analysis of single cases showed the expecteddissociation patterns. A first group of subjects showed apattern of deficit that corresponds to the diagnosis of surfacedysgraphia, while a second group showed a patterncorresponding to the diagnosis of phonological dysgraphia.A further group of subjects showed mixed damage both forwords with unpredictable spelling and for regular non-words,but better performance for regular words. There are twopossible explanations of this mixed pattern of impairment.According to the classical logogen model (see Fig. 3), thispattern of disruption could be explained as being the resultof two separate functional lesions, one at the level ofthe auditory-to-phonological conversion, the other of theorthographic output lexicon; writing to dictation wouldtherefore be possible only for regular words along an indirectcircuit passing through the phonological output lexicon,the phonological buffer and the phonological-to-orthographicconversion unit. However, a pattern of disruption charac-terized by a selective impairment in writing words withunpredictable spelling and non-words, with an almostpreserved spelling of regular words could also account forthe mutual interaction of the lexical and the subword-levelroutines with the writing of regular words (as a consequenceof cerebral damage, both routines feed the orthographicbuffer with a blurred representation); the performance ofmixed dysgraphic patients on writing both words withunpredictable orthography and non-words is thereforeimpaired. An interaction of the two routines (‘summation’hypothesis), however, is open to various differinginterpretations. A first hypothesis is that the two routinesalready interact in normal subjects; a similar account hasbeen proposed for normal reading by Hillis and Caramazza(1991). Alternatively, the interaction of the two routines maybe a compensatory phenomenon that only accounts for thepattern of performance of mixed dysgraphic patients: whileneither of the two routines is sufficient for writing words withunpredictable orthography and non-words, their interaction

allows a better performance with the writing of regularwords. A further account assumes the so called ‘horse race’explanation, for which each of the two routines processregular words independently, both in normal subjects and inmixed dysgraphic patients. Two independent race horseswould increase, a priori, the probability of better performancein normal subjects, as well as the possibility of success inthe mixed dysgraphic patients.

In the introduction, a possible selective impairment of thesyllabic subword-level conversion rules was predicted. Infact, three patients showed a dissociated damage of theserules alone. Another prediction made was a possible damageto the auditory-to-phonological conversion, a disorder thatwould determine a less severe impairment of words composedentirely of continuant phones (vowels and fricative, liquid ornasal consonants), words that are thus more easily analysedalong the auditory-to-phonological conversion unit. Thisphenomenon seems to be rare and was found in onlyfour cases.

A frequency effect is usually more common in phonologicalthan in surface dysgraphic disorders, as could be predictedfrom a writing performance along the lexical routine only.

A final issue is the possible difference underlying theprocess of writing in English and in a language with shalloworthography like Italian. In a recent study, Ardilaet al.(1996)stressed the greater relevance of the subword-level routinefor the processing of written language in Spanish. However,the writing task used by these authors did not include wordswith irregular or unpredictable orthography and non-words;unfortunately, the absence of these variables precluded,perse, an identification of the dysgraphic patterns underlyingphonological and surface dysgraphia. The results of thepresent study demonstrated that current psycholinguisticmodels of written language also apply to languages withshallow orthography. An important difference, however, isthe degree of activity of each routine; the lexical route iscrucial in languages with irregular spelling like English andFrench, but less important in a language with predominantlyshallow orthography like Italian.

AcknowledgementsWe wish to thank Erminio Capitani and the anonymousreferees ofBrain for their helpful critical comments andFrances Anderson and Rosemary Allpress for her carefulreview of the English version of the manuscript. This researchwas supported by a Grant from the Italian Ministerodell’Universita e della Ricerca Scientifica e Tecnologica(MURST) to C.L. and from the Fondazione Valduce toA.D.T. Portions of this paper were presented at the 15thEuropean Workshop on Cognitive Neuropsychology,Bressanone, January 19–24, 1997, and at the NationalCongress of the Associazione Italiana di Psicologia, Sezionedi Psicologia Sperimentale, Capri, September 22–24, 1997.

1732 C. Luzzattiet al.

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Received October 8, 1997. Revised February 1, 1998.Second revision May 1, 1998. Accepted May 18, 1998

Diagnosis of writing disorders 1733

AppendixDerandomized list of the items used in the writing task [WF5 word frequency (from Bortoliniet al., 1972)]

Section A

Part Words WF Part Words WF

1 mare 2231 mano 1961 sole 1731 muro 931 vino 781 mulo 101 lume 101 faro 91 filo 51 remo 02 lavoro 2672 numero 1492 nuvola 272 minerale 262 fenomeno 212 semaforo 02 sinonimo 02 sifone 02 visone 02 somaro 03 senso 1233 forma 1193 frase 343 marmo 333 nervo 193 frana 83 sfera 03 farsa 03 selva 03 salsa 04 valle 834 ferro 694 messa 474 sonno 414 villa 304 molla 74 muffa 54 masso 04 renna 0

Section B

Words WF

cane 163scala 49gara 40gola 34scopa 0chiave 48schifo 23scheda 10ghiro 0ghisa 0valigia 48bacio 41fascia 23adagio 12

5 capo 1455 tipo 1285 dito 455 coda 95 buco 55 topo 115 buca 95 baco 85 tubo 35 diga 06 monte 1446 clima 886 festa 786 spesa 506 prato 496 fusto 136 trave 76 lardo 06 mirto 06 stelo 07 notte 2287 letto 1767 matto 877 latte 327 babbo 277 lutto 107 fetta 97 tappo 07 ratto 07 mappa 08 strada 3118 fronte 1208 stampa 288 sponda 118 nastro 88 crosta 88 tromba 68 frusta 38 fulcro 08 filtro 0

ascia 0

1734 C. Luzzattiet al.

Section C

Words WF

societa 110coscienza 34scienza 31igiene 5usciere 0ente 202scena 45conoscenza 20ascella 0macello 0migliaia 42paglia 8aglio 0caviglia 0vaniglia 0Italia 256milione 145olio 74vigilia 10balia 8segno 215compagno 59ognuno 35pugnale 9ragno 0niente 588genio 13geranio 7paniere 0cerniera 0libro 86litro 12fibra 9zebra 0cetra 0quattro 193labbro 34febbre 16fabbro 0spettro 0quarto 51aquila 9squalo 0quarzo 0squama 0liquore 11quota 0equo 0iniquo 0obliquo 0cuore 136scuola 102scuotere 19cuoio 12cuoco 9

Section D

Words WF

hobby 0brandy 0blue jeans 0baby-sitter 0weekend 0robot 0chalet 0nightclub 0

Section E

Part Non-words

1 nise1 nifo1 ralo1 vona1 relo2 vimane2 forela2 rinafo2 ramasola2 lesonimo3 fella3 seffa3 sovva3 nissa3 sinno4 tido4 pabo4 bita4 dute4 puda5 nitta5 loppa5 rebba5 mippo5 satto