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DUI Hot TopicsMiriam Norman, TSRP

HGN as Evidence of Impairment - How to Use This Evidence in Trial

Widmark’s Equation- How to Use This Evidence in Trial

Observable Signs of Impairment-Using Visual Exhibits in Trial

Lui Confrontation Briefing-How to Use the Reviewer or Supervisor in

Trial

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HGN as Evidence of ImpairmentHow to Use This Evidence in Trial

HORIZONTAL GAZE NYSTAGMUS

Alcohol and certain other drugs cause this phenomenon.

Drug categories: Depressants, Inhalants, Dissociative

Anesthetics (PCP), and also caused by Brain Stem Trauma

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Acquired Anticipatory (Induced)

Arthrokinetic (Induced, Somatosensory)

Associated (Induced, Stransky’s)

AudioKinetic(Induced)

Bartel’s (Induced)

Brun’s Centripetal Cervical (NeckTorsion, Vestibular-Obasilar, Artery Insufficiency)

Circular/Elliptic/Oblique

Congenital (Fixation, Hereditary)

Convergence

Convergence Invoked

Disassociated, Disjunctive

Downbeat Drug Induced (Barbituate, ow Tie, Induced)

Epileptic (Ictal) Flash induced

Gaze-Evoked (Deviational, Gaze-Paretic, Neurasthenic, Seducible, Setting-in)

Horizontal Induced (provoked) Intermittent Vertical Jerk Latent/Manifest Latent (Monocular Fixation, Unimacular)

Lateral Medullary Lid Miner’s (Occupational) Muscle Paretic (Myasthenic)

Optokinetic (Induced, Optomotor, Panoramic, Railway, Sigma)

Optokinetic After-Induced (Post-optokinetic, Reverse Post Optokinetic)

Penduar (Talantropia Periodic/Aperiodic Alternating

Physiologic (End Point/Fatigue)

Pursuit After Induced

Pursuit Defect Pseudo Spontaneous

Rebound Reflelx (Baer’s) See-Saw Somatosensory Spontaneous Stepping Around

Torisional Uniocular Upbeat Vertical Vestibular (Caloric, Compensatory, Compression, Positional/Alcohol, Pseudo Caloric)

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47 Types of Nystagmus!

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47 Types of Nystagmus!

• Vestibular Nystagmus:

• Rotational Nystagmus (occurs when the person is spun around or rotated rapidly causing the fluid in the inner ear to be disturbed); Post rotational Nystagmus (closely related to rotational nystagmus; once the spinning stops, the fluid in the inner ear will remain disturbed for a period of time).

• To illustrate rotational and post rotational nystagmus, swirl a glass of water several times. Stop swirling the glass, the water will continue to spin for a short period of time.

• Neither rotational nystagmus nor post rotational nystagmus will interfere with the HGN test because of the conditions under which they occur.

• Caloric Nystagmus- occurs when fluid motion in the canals of the vestibular system are stimulated by temperature as by putting warm water in one ear and cold ear in the other.

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Examples of Other Forms of NystagmusPost-Rotational Caloric

Examples of Optokinetic Nystamus and HGNOptokinetic Nystagmus HGN

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47 Types of Nystagmus!

• Optokinetic Nystagmus- occurs when the eyes fixate on an object that suddenly moves out of sight, or then the eyes watch sharply contrasting moving images. (e.g., strobe lights, rotating lights, rapidly moving traffic, cell phone screens as they scroll down.)

• “During the Horizontal Gaze Nystagmus test, the suspect is require to fixate the eyes on a penlight, pencil or similar object that moves in accordance with the HGN testing procedures, thus optokinetic nystagmus will not occur. The movement of the stimulus and the fixation on the stimulus by the subject precludes this form of nystagmus from being observed by the officer.”

• Physiological Nystagmus is a natural nystagmus that keeps the sensory cells of the eye from tiring. Most common form of nystagmus, but these tremors are generally too small to be seen and invisible to the naked eye.

HGN as Evidence of Impairment!

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How Will You ExplainThis Evidence to the JURY?

TALKING ABOUT HGN In Trial

• HGN: • Involuntary jerking of the eyes occurring as the eyes gaze towards the

side• Readily noticeable when a person is impaired• Not something that the person is aware of or can control

• Give an example:• Windshield wipers• Marble on smooth/sand surface• Sprinklers

§HGN: oInvoluntary jerking of the eyes occurring as the eyes gaze towards the sideoReadily noticeable when a person is impairedoNot something that the person is aware of or can control§Give an example:oWindshield wipersoSprinklers

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Tunnel Vision

Impaired Eye Movements & Driving

Impaired Eye Movements & Driving

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Eye Movements & DrivingScanning RoadwayScanning Roadway

35-45 deg35-45 deg

40-60 deg40-60 deg

Eye Movements & DrivingEye Movements & DrivingViewing in MirrorsViewing in Mirrors

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Defense Challenges to HGN• The officer is not an optometrist!!!!üYou do not need to be; we are trained to differentiate between HGN

and other types of nystagmus. • Lots of different types of nystagmus!• END POINT NYSTAGMUS • FATIGUE NYSTAGMUS üWe are trained to differentiate between HGN and other forms of

nystagmus; the process of HGN ensures that all other external causes of nystagmus are eliminated.

• Post-rotational (crash) was the nystagmus seen. • It was cold out and the window was down; thus caloric nystagmus

was seen! üReally…. No.

Defense Challenges to HGN§ The speed of each pass.ü“Approximately”üWatch your video and time it!

§ The stimulus is too far or too close.ü“Approximately 12-15 inches”

§ Insufficient number of passes.üPause between the equal tracking (medical checks) and lack of

smooth pursuit. üAmount of time stimulus held at maximum deviation. (At least 5

seconds to avoid seeing end point nystagmus, no longer than 29 seconds to avoid seeing fatigue nystagmus). üDistinct and sustained nystagmus at maximum deviation.

NHTSA Manual VIII-5-7

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Defense Challenges to HGN

§Did not testify to checking for each clue 2x

§Overhead lights of patrol car or passing traffic caused nystagmus:üNot optokinetic nystagmusüEliminated because focusing on the stimulus

§Angle of onset - did you have a protractor to estimate 45°??:ü12 to 15 out; 12 to 15” over! üStill see some white in the eyes NHTSA Manual VIII-5-7

Widmark’s Equation v. Retrograde Extrapolation

How to Use This Evidence in Trial

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Retrograde Extrapolation

Thanks to alcoholism.about.com

Retrograde Extrapolation• Used to estimate an ethanol level at an earlier

time

BAC (t+n) = BAC + (0.015 g/100 mL/hr x n hours)BAC (2 hr) = 0.07 + (0.015 g/100 mL/hr x 2 hr)BAC (2 hr) = 0.07 + (0.03)

• ***Use with caution***: multiple conditions must be met to use this

Burn-Off Range:

.01 / hour Avg: .015 / hour .02 / hour

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Retrograde Extrapolation

• Some ‘conditions’:• Post absorptive• Starting / known value > 0.02 g/100 mL (or g/210 L)• Time extrapolating to is also post absorptive

• Thanks to alcoholism.about.com

Widmark’s Equation

• Used to estimate a BAC from a given number of drinks OR estimate

a number of drinks from a BAC. • Need: weight, gender, and number

or drinks or BAC.

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Widmark’s Equation

BAC = # x oz x % x 5.2 / wt x ρ

# = number of standard drinksoz = size of each drink% = percent alcohol per drink5.2 = constant, unified conversion for imperial to metric units

wt = weight of person, in poundsρ = water distribution coefficient (male ~ 0.68, female ~ 0.55)

How should you use this in trial??? With whom???

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Observations and Signs of ImpairmentHow to Use This Evidence in Trial

Defendant’s Signs of ImpairmentEyes Red, Dilated with Droopy Eyelids

Car Crashed into Ditch

Slow Deliberate Speech

Difficulty presenting ID card from her wallet

Lack of Convergence, Eyelid Flutters Unable to remember tasks

Walk and Turn Clues

Marijuana and Pipe Found

Admits to 2 glasses of wine prior to driving

Admitted to Smoking Marijuana

Finger to Nose Test

Urine Contained THC MetabolitesPoor balance

Below Normal Blood Pressure

Leg Tremors

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CREDIBILITY OF THE WITNESSYou are the exclusive judges of the credibility of the

witnesses.

Truth or Fiction?

Inconsistent Statements

Interest in Outcome?

Bias or Motive

Effects of Alcohol? Ability to Recall

Believable or Not

Substance of Testimony

Manner While Testifying

Conduct and AttitudeConduct and Attitude

Manner While Testifying

Truth or Fiction?

Substance of Testimony

Believable or Not

Ability to RecallEffects of Alcohol or Drugs?

Bias or Motive

Inconsistent Statements

Interest in Outcome? Credibility?

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Lui Confrontation Issues w/ AnalystsHow to Use This Evidence in Trial

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Your Analyst Is Unavailable… Understand the Issues!

Who will you potentially call as a witness?

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MIRIAM NORMAN

Traffic Safety Resource Prosecutor

Miriam.norman@seattle.gov