Cognitive Tests for driver screening Kate Radford PhD, MSc

1. Cognitive Testsfor driver screeningKate Radford PhD, MSc Occupational Therapist Senior Lecturer University of Central Lancashire

2. 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

3. 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

4. Why do we need cognitive tests / screening?

5. 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

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

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

8. Time Pressure

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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.

16. Numbers of drivers with dementia 1000’s • Estimated prevalence of drivers with dementia in Ontario Hopkins et al Can J Psych 2004, 49(7)434-8

17. 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

18. Estimate: drivers with dementia in UK 1000’s

19. 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 it’s a growing problem

20. What do cognitive tests do?

21. Uses of cognitive tests • Screening • DiagnosisIs 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

22. Interpreting Tests • Comparison with test norms • Scaled scores • Percentiles • z scores

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

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

25. Normal curve

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

27. 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

28. Compare with premorbid ability • Depends on accuracy of estimation of premorbid level

29. 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

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

31. 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

32. Interpreting Scores • Interpret in context of range of tests • Scores don’t prove or disprove anything • Performance normal for that individual? • Other reasons for performance • Background information

33. 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

34. 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?

35. 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

36. 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

37. 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

38. 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

39. Introduction to some commonly used tests: • Mini Mental State Examination (MMSE) • Trail Making Test • Stroke Drivers Screening Assessment • Star cancellation

40. 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.

44. 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)

46. 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 <24 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)

47. 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

48. 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 seven’s 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

49. MMSE? Lincoln NB, Radford KA, et al, 2006

50. The Stroke Drivers Screening Assessment