Presentation on theme: "1 Cognitive Tests for driver screening Kate Radford PhD, MSc Occupational Therapist Senior Lecturer University of Central Lancashire."— Presentation transcript:
1 Cognitive Tests for driver screening Kate 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 14.05-14.35Introduction to some commonly used tests What are they, what do they measure/ assess, administration, common questions/ problems 14.40-15.05Practical session (Group work) 15.05- 15.15Questions 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
5 1.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.
9 Screening - 2 tier 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? YES NO Level 1: Screening Process 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 No significant impairments affect driving ability Screen for problems and potential to impact on safe driving ? Driving Abilities Significant impairments affect driving ability Safe to drive Declaration of unfit to drive Driving Assessment If Yes…
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 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. Increases with age
16 Numbers of drivers with dementia Estimated prevalence of drivers with dementia in Ontario Hopkins et al Can J Psych 2004, 49(7)434-8 1000’s
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
21 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
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
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 No. of CasesPredicted Group Membership Actual Group PassFail Pass37362 95%5% Fail1559 35.7%64% Percent of grouped cases correctly classified: 86.5% Positive Predictive Value: 60% Negative Predictive Value: 97.3% Classification results by Discriminant Equation (TBI)
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
53 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)
54 How does SDSA compare with usual practice? SDSA Group Road Test Control Group Road Test PassFailPassFail Predicted Pass 6 (75%)310 Predicted Fail 216 ( 84%) 14 Accuracy81%56%
61 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
62 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 Parkinson’s 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; 21:1044-1051 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)
63 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
64 SDSA Advantages Short test Battery, < 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.
65 Fitness to Drive and Cognition Multi-disciplinary Working Party Report, British Psychological Society, Jan 2001, ISBN:1 85433 324 0 Reviews suggest the need for a battery of Neuropsychological tests (Lundberg 1997, McKenna 1998) It’s a complex issue (Mazer et al, 2004, Brooks and Hawley 2005, Heikkila and Tampani 2005)
66 Opportunity to take part Implementation research
67 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.
68 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.
69 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.
70 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 2006;21:1044-1051 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 85:324–8. 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.