Cognitive Tests for driver screening Kate Radford PhD, MSc

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Cognitive Tests for driver screeningKate
Radford PhD, MSc

• Occupational Therapist
• Senior Lecturer
• University of Central Lancashire

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Content of presentation
13.45-14.00 Cognitive assessment for driver
screening Why is it needed ? Where does it
fit (with existing procedures)? Relevance Vs
functional assessment Basic principles of
assessment 14.05-14.35 Introduction to some
commonly used tests What are they, what do they
measure/ assess, administration, common
questions/ problems 14.40-15.05 Practical
session (Group work) 15.05- 15.15 Questions and
feedback
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Learning Outcomes

• Become familiar with basic concepts of cognitive
  assessment
• Consider the relevance of cognitive assessment
  and fit with existing procedures
• Discuss experiences of using cognitive tests
• Explore practical issues in administration.
  Scoring and interpretation

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• Why do we need cognitive tests / screening?

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• The presence of brain damage is
• a poor predictor of driving ability.
• Giddens et al. 1983, Galski et al. 1992
• Haselkorn et al. 1998
• 2. Driving is a complex ability and Ax is a
  complex issue - (Mazer et al, 2004, Brooks and
  Hawley 2005, Heikkila and Tampani 2005)
• 3. Driving is an over-learned skill

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Fitness to Drive?
Visual Deficits preclusion Physical
disabilities adaptations Cognitive deficits
problem


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• Cognitive deficits hidden disabilities
• Assessment may provide insight into performance
  that may be difficult to measure or capture
  functionally.

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Time Pressure
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Screening - 2 tier process
Level 1 Screening Process

• Driving specific questions in Clinical Setting
• E.g. Does the client have a car? Does the client
  have a valid license?
• Does the client still drive?

NO
YES

• Screen for problems
• Medical history and medication
• Vision and perception
• Cognition
• Psychomotor skills

If transport is an important issue for the person
and family, alternative methods should be
discussed
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Screening - 2 tier process
If Yes
Screen for problems and potential to impact on
safe driving
No significant impairments affect driving ability
Significant impairments affect driving ability
? Driving Abilities
Declaration of unfit to drive
Safe to drive
Driving Assessment
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Level 2 Specialist Assessment

• In-house Assessment
• Medical History, Physical profile, Cognitive
  Assessment
• Visual/Perceptual Assessment, Behavioural
  assessment

In/Out Evaluation - Are adaptations needed?

• Stationary behind-the-wheel assessment
• Access to controls
• Determine adaptive equipment needs

Off-road (Closed Course) Evaluation
ON-ROAD ASSESSMENT
UNSAFE
SAFE
Not Yet Safe
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In practice
Many stroke/TBI survivors resume driving without
assessment or advice Ebrahim et al.
1988 Pidikiti Novack 1991 Fisk et al.
1997 Hawley, 2001 Johnston et al.
2004 Mazer et al. 2004
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Practicalities the UK licensing system

• Relies on
• The doctor/medical professional knowing the
  basics of the licensing system
• The doctor/medical professional informing you of
  your legal obligation to inform the DVLA
• The driver informing the DVLA of any medical
  condition that may infringe fitness to drive

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Growing problem

• Every year in the UK 130,000, people have a
  stroke (NAO, 2005) 25,000 of working age.
• One million people a year sustain a traumatic
  brain injury of these 21,600 will have moderate
  or severe brain injury.
• The population is ageing
• Increase in the numbers of car owners/drivers

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Dementia Incidence
Increases with age

• Affects about 1 of men and women between 70 and
  80 increasing to about 6 in those aged 85 years
  and older
• Findings broadly in line with others in Europe,
  Asia,
  and the USA
• Matthews et al. The incidence of dementia in
  England and Wales findings from the five
  identical sites of the MRC CFA study. PLoS
  Medicine 2005 2 e193.

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Numbers of drivers with dementia
1000s

• Estimated prevalence of drivers with dementia in
  Ontario
• Hopkins et al
• Can J Psych 2004, 49(7)434-8

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• In 2005, it is estimated that 73 of men and 35
  of women aged 70 and over held a full car driving
  licence, compared to 81 of all men and 63 of
  all women.
• Transport Statistics of Great Britain,
  Department for Transport 2006

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Estimate drivers with dementia in UK
1000s
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Summary justification

• Screening - to identify who needs further
  assessment
• Road assessments for everybody are expensive and
  time consuming, therefore an objective screening
  test would be useful
• Decisions by doctors subjective and not based on
  any standard scale introduces some
  standardisation to decision making
• To identify underlying impairments which may
  impact on driving performance and behaviours
• Because driving is a complex task
• Because its a growing problem

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What do cognitive tests do?
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Uses of cognitive tests

• Screening
• Diagnosis Is there evidence of organic brain
  dysfunction?
• Monitoring Does cognitive performance change over
  time?
• Evaluation What is the nature and extent of
  cognitive impairment?

Psychometric properties determine use
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Interpreting Tests

• Comparison with test norms
• Scaled scores
• Percentiles
• z scores

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Normative sample

• Scores of a reference group
• Sample size
• Age
• How and where sample were selected
• Education
• Ethnicity
• How recent?

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Interpreting Tests

• Comparison with test norms
• Scaled scores
• Percentiles
• z scores
• Comparison with premorbid ability
• Comparison with cut-off score
• Criterion referenced testing

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Normal curve
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Percentiles

• Normal distribution
• of scores that fall at or below that score
• Mid-point 50 percentile
• e.g. VOSP

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Why standardise scores?

• Compare against norms
• Compare tests with different scales of
  measurement
• Different forms all based on mean and SD
• SD spread of scores around the mean

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Compare with premorbid ability

• Depends on accuracy of estimation of premorbid
  level

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Comparison with cut-off

• Cut-off may be set for
• Sensitivity the proportion of positives
  correctly identified by the test (presence of
  condition)
• Specificity the proportion of negatives
  (absence of condition)
• Trade-off between sensitivity and specificity

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Classification results by Discriminant Equation
(TBI)
No. of Cases Predicted Group
Membership Actual Group
Pass Fail Pass 37 36 2 95 5 F
ail 15 5 9 35.7 64 Percent of
grouped cases correctly classified
86.5 Positive Predictive Value 60 Negative
Predictive Value 97.3
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Criterion referenced testing

• Does test performance predict behaviour?
• Is ability at a level that would enable someone
  to carry out particular task?
• Drive a car
• e.g. Stroke Drivers Screening Assessment

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Interpreting Scores

• Interpret in context of range of tests
• Scores dont prove or disprove anything
• Performance normal for that individual?
• Other reasons for performance
• Background information

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Summary

• Tests for different purposes
• Test interpretation depends on development
  purpose how it is scored and on the
  standardisation sample
• Interpretation requires
• Estimate of previous ability
• Understanding of behavioural factors and mood

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Points to Consider

• Are we using tests as they were designed?
• Are we comparing like with like?
• Do we know what value the patient places on the
  tests and their results?

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Inaccurate performance and other issues

• Concurrent psychological distress
• Fatigue
• Concurrent physical illness or injury
• Pre-existing low capacity
• Malingering
• Age, education, culture and language
• Compensatory strategies

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Formulation

• Cognitive assessment is just one part of the
  assessment formula other information derived
  from the patient and other sources (background
  information, semi-structured interview,
  relative/carer input, observation, brain imaging,
  multi-disciplinary reports), together with
  cognitive assessment
• Any of these methods in isolation (especially
  cognitive assessment) will be much less
  meaningful and more prone to misinterpretation

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Cognitive assessment Vs Functional Assessment

• Cognitive tests are just one part of a complete
  neuropsychological assessment
• Also addresses practical and functional
  consequences of impairment e.g. affect on ADL.
  Work, leisure, driving
• (usually done via interviews and observation)
• and how mood and behaviour might be affected by
  brain dysfunction
• E.g. depression negatively impacts on performance

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Relevance Vs functional assessment

• Part of the same overall process
• Interviews with patients/ family members
• Functional on road testing procedures are
  arguably the observational parts of a
  comprehensive neurological assessment

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Introduction to some commonly used tests

• Mini Mental State Examination (MMSE)
• Trail Making Test
• Stroke Drivers Screening Assessment
• Star cancellation

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Trail Making Test

• Army Individual Test Battery (1944)
• Test of visuomotor tracking, complex visual
  scanning an attention with a motor component - it
  tests how effectively the patient responds to a
  complex visual array, mental sequencing ability
  and shifting attention
• Different forms and scoring instructions Reitan
  (undated)
• Advantages
• 5-10 mins, simple, transportable, little
  specialist training
• in public domain
• a number of studies found a significant
  relationship between performance on the TMT and
  on road driving performance.

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Star cancellation

• Halligan, Cockburn and Wilson, (1991)
• Behavioural Inattention Test
• Un-timed test of visual inattention
• Available in 2 versions (allow retesting)
• Mean score of misses for 50 norms 0.28 (at
  most 2 missed)
• Cut of score of 3 or more failure (inattention
  present)

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Mini Mental State Examination

• Folstein Folstein McHugh, (1975)
• Mot widely used brief screening instrument for
  dementia
• Tests a restricted set of cognitive functions
  quickley and simply
• Scores lt24 abnormal for dementia but higher cut
  offs for specific conditions and people of
  different ages. E.g 27 for MS, 25 for educated
  people with dementia, 29 (ages 40-49 28 50-59
  26- 80-89)

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• Advantages
• 5-10 mins to administer
• No specialist training
• Minor cultural or language modifications
• Scores not related to depression severity
• High test retest and inter -rater reliability
• Disadvantages
• False negatives (high scores in dementia
  patients) hence diff to interpret indiv. scores

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MMSE Instructions

• Orientation
• e.g. Can you tell me todays date
• Which season is it?
• Registration and recall naming three common
  objects and recalling after a delay
• Attention and calculation subtracting sevens
  from 100
• Spell world backwards
• Language naming objects
• Repeating No iffs ands or buts
• Reading CLOSE YOUR EYES
• Following a three stage command
• Construction copying a drawing

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MMSE?
Lincoln NB, Radford KA, et al, 2006
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The Stroke Drivers Screening Assessment
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Development of Stroke DriversScreening Assessment

• SDSA
• Nouri Lincoln Clin Rehabil 1992 6 275-281

79 stroke patients Cognitive Assessment
BSM Road Test
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Construct Validity

• Radford 2000
• 93 Stroke patients
• SDSA
• Cognitive Tests
• RMT
• Stroop
• Trail Making
• Cognitive Estimates
• VOSP Cube Analysis
• Measures executive abilities and attention

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Background SDSA - Predicts on the road
performance in stroke patients (Nouri,
Tinson and Lincoln, 1987, Nouri and Lincoln,
1992) - Found to be a more accurate predictor
than the advice of the GP or the DVLA
(Nouri and Lincoln, 1993)
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How does SDSA compare with usual practice?
SDSA Group Road Test SDSA Group Road Test Control Group Road Test Control Group Road Test
Pass Fail Pass Fail
Predicted Pass 6 (75) 3 10 10
Predicted Fail 2 16 ( 84) 1 4
Accuracy 81 81 56 56
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Dot cancellation
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SDSA -Square Matrices Directions
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Square Matrices Compass
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SDSA - Road Sign Recognition Test
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Intended use
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Use of SDSA

• Screening procedure to decide who to refer for
  on road assessment
• Pass
• May need physical adaptations
• Borderline (-0.5 - 0.5) (Lundberg et al 2003)
• referral to assessment centre which involves
  cognitive assessment
• Fail
• if early wait and retest (Lincoln Fanthome
  1994)
• If late not fit to drive

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Diagnosis Specific Equations

• Radford KA et al Validation of the Stroke
  Drivers Screening Assessment for people with
  Traumatic Brain Injury. Brain Injury 2004 18
  775-786.
• KA Radford et al The Effects of Cognitive
  Abilities on Driving in People with Parkinsons
  Disease. Disability Rehabilitation 2004 26
  65-70.
• Lincoln NB et al The Assessment of Fitness to
  Drive in People with Dementia Int J Geriatric
  Psychiatry 2006 211044-1051
• LINCOLN, N.B. and RADFORD, K.A., 2007. Cognitive
  abilities as predictors of safety to drive in
  people with multiple sclerosis. Multiple
  Sclerosis 2008, 14(1)

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Conclusions

• SDSA on its own good for stroke drivers
• Extra assessments needed for other client groups
• Predictive equations need validation
• Information can be used to guide clinical practice

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SDSA

• Advantages
• Short test Battery, lt 30 minutes to administer
• Accurate at identifying safe drivers with TBI
  and Stroke and those needing additional on-road
  testing.
• Criterion Validity, ecological validity
• Helps inform decisions about driving and adding
  standardised assessment where currently little
  exists.
• Disadvantages
• Instructions and interpretation complex for
  clinicians?
• Tests still needed to identify unsafe drivers
  with TBI
• Further validation needed.

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Fitness to Drive and Cognition

• Multi-disciplinary Working Party Report, British
  Psychological Society, Jan 2001, ISBN1 85433 324
  0
• Reviews suggest the need for a battery of
  Neuropsychological tests
  (Lundberg 1997, McKenna 1998)
• Its a complex issue
• (Mazer et al, 2004, Brooks and Hawley
  2005, Heikkila and Tampani 2005)

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Opportunity to take part

• Implementation research

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References

• Crawford J.R, Parker, D.M., McKinlay, W.W.
  (1992) A Handbook of Neuropsychological
  Assessment. Hove Lawrence Erlbaum.
• Evans, J.J. (2003). Basic concepts and principles
  of neuropsychological assessment. In P. Halligan,
  U. Kischka, and Marshall, J.C. (Eds.) Handbook of
  Clinical Neuropsychology (pp.15-26). Oxford
  Oxford University Press.
• Lezak, M.D., Howieson, D.B., Loring, D.W.,
  Hannay, H.J., Fischer, J.S. (2004).
  Neuropsychological Assessment (4th Edition).
  Oxford Oxford University Press.
• Miller, E. (1992). Some basic principles of
  neuropsychological assessment. In J.R. Crawford,
  D.M. Parker, and W.W. McKinlay (Eds.) A Handbook
  of Neuropsychological Assessment (pp.10-11).
  Hove Lawrence Erlbaum.

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References

• Chaytor, N. Schmitter-Edgecombe, M. (2003) The
  ecological validity of neuropsychological tests
  a review of the literature on everyday cognitive
  skills. Neuropsychology Review, 13, 181-197.
• Evans, J.J. (1996) Selecting, administering and
  interpreting cognitive tests. Bury St Edmunds
  Thames Valley Test Company.
• Lezak, M.D. (2004) Neuropsychological
  Assessment. Oxford Oxford University Press.
• Spreen, O. Strauss, E. (1998) A compendium of
  neuropsychological tests. Administration norms,
  and commentary. New York Oxford University Press.

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References

• Brooke MM, Questad KA, Patterson DR, Valois TA
  (1992) Driving Evaluation after traumatic brain
  injury. American Journal of Physical Medicine
  and Rehabilitation, 71, 177-182.
• Ranney TA (1994) Models of driving behaviour A
  review of their evolution. Accident Analysis and
  Prevention, 26(6), 733-750.
• Korteling JE and Kaptein MA (1996)
  Neuropsychological driving fitness tests for
  brain damaged subjects. Archives of Physical
  Medicine and Rehabilitation, 77, 138-146.
• Mazer BL, Korner-Bitensky NA, Softer S (1998)
  Predicting ability to drive after stroke.
  Archives of Physical Medicine and Rehabilitation,
  79, 743-750.
• Lundqvist A, (2001), Neuropsychological aspects
  of driving characteristics, Brain Injury, 15(11)
  981-994.
• Lundqvist A and Rönnberg J, (2001) Driving
  problems and adaptive driving behaviour after
  brain injury a qualitative assessment.
  Neuropsychological Rehabilitation, 11, 171- 185.

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References

• SDSA Development
• Nouri FM and Lincoln NB (1994) The Stroke Drivers
  Screening Assessment. Nottingham Rehab. UK.
• Nouri FM and Lincoln NB (1992) Validation of a
  cognitive assessment Predicting driving
  performance after stroke. Clinical
  Rehabilitation, 6, 275-281.
• Nouri FM and Lincoln NB (1993) Predicting driving
  performance after stroke. British Medical
  Journal, 307, 482-483.
• Nouri FM, Tinson DJ, Lincoln NB (1987) Cognitive
  ability and driving after stroke. International
  Disability Studies, 9, 110-115.
• Lincoln NB. Fanthome Y, (1994) Reliability of
  the Stroke Drivers Screening Assessment, Clinical
  Rehabilitation. Vol 8(2), 157-160
• Radford KA Validation of the Stroke Drivers
  Screening assessment for patients with an
  acquired neurological disability, 2000, Phd
  Thesis University of Nottingham
• Dementia
• Lincoln NB, Radford KA, Lee E, Reay AC, The
  Assessment of Fitness to Drive in People with
  Dementia, International Journal of Geriatric
  Psychiatry 2006211044-1051
• TBI/Stoke
• Radford KA, Lincoln NB, Murray-Leslie C. 2004c.
  Validation of the Stroke Drivers Screening
  Assessment for people with Traumatic Brain
  Injury. Brain Injury 18 775-786.
• Radford KA, Lincoln NB. 2004. Concurrent validity
  of the Stroke Drivers Screening Assessment. Arch
  Phys Med Rehabil 853248.
• PD
• Radford KA, Lincoln NB. The Effects Of Cognitive
  Abilities On Driving In People With Parkinson's
  Disease, Disability and Rehabilitation, 2004, 26
  (2) 65 - 70.
• MS
• LINCOLN, N.B. and RADFORD, K.A., 2007. Cognitive
  abilities as predictors of safety to drive in
  people with multiple sclerosis. Multiple
  Sclerosis 2008, 14(1) 123-128.

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Stroop
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Stroop