Investigating Fitness to Drive in Older Drivers with Cognitive Impairment Anna Devlin B.App.Sci.

181 Pages·2014·18.02 MB·English

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Investigating Fitness to Drive in Older Drivers with Cognitive Impairment

Anna Devlin
B.App.Sci. (Psychology) Honours

Submitted in partial fulfillment of the requirement for the degree of
Doctor of Psychology (Health)
Deakin University
March 2013
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Table of Contents
Abstract ....................................................................................................................... ix
Acknowledgements .................................................................................................... xii
List of Publications .................................................................................................... xiii
Conference Presentation ............................................................................................ xiv
Terminology and Definitions ..................................................................................... xv
Thesis Overview ......................................................................................................... 16
Chapter 1: Introduction .............................................................................................. 18
The Older Driver Problem ...................................................................................... 18
The extent of safety risk for older drivers. .......................................................... 20
The crash patterns of older drivers with cognitive impairment. ......................... 21
The problem for licensing authorities. ................................................................ 22
The problem for health professionals. ................................................................. 25
The importance of maintaining mobility. ........................................................... 27
Addressing the problem of older drivers with cognitive impairment. ................ 29
Chapter 2: Age-Related Cognitive Impairment and Driving ..................................... 31
Cognitive Impairment Defined ............................................................................... 31
Prevalence of mild cognitive impairment. .......................................................... 33
Assessment of cognitive impairment. ................................................................. 34
Telephone interviews for assessing cognitive impairment. ................................ 36
Models of Driver Performance and Cognitive Components .................................. 37
Information processing model of driver behaviour. ............................................ 37
Michon model of driver behaviour. .................................................................... 38
On-Road Driving Performance and Cognitive Impairment .................................... 40
Driver Error and Neuropsychology Test Performance ........................................... 43
Executive function. ............................................................................................. 45
Chapter 3: Older Driver Intersection Approach ......................................................... 47
Braking Behaviour of Older Drivers ...................................................................... 47
Braking Behaviour of Older Drivers with Mild Cognitive Impairment ................. 49
Summary ................................................................................................................. 51
Chapter 4: Rationale and Aims of Study 1 ................................................................. 52
Rationale of Study 1 ............................................................................................... 52
Aims and Objectives of Study 1 ............................................................................. 52
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Paper 1: Investigating Driving Behaviour of Older Drivers with Mild Cognitive
Impairment Using a Portable Driving Simulator .................................................... 53
Preamble to Paper ................................................................................................... 53
Paper 1 .................................................................................................................... 53
Chapter 5: Self-Regulation of Older Drivers ............................................................. 62
Introduction ............................................................................................................. 62
Self-Regulation Defined ......................................................................................... 62
Theoretical Models of Self-Regulation .................................................................. 63
Michon hierarchical model of driver compensatory behaviours ........................ 63
Driving as an Everyday Competence Model. ..................................................... 65
Self-Regulation and Driver Insight ......................................................................... 66
Self-Regulation, Driver Insight and Cognitive Impairment ................................... 68
Summary ................................................................................................................. 69
Chapter 6: Self-Regulation of Older Drivers with Cognitive Impairment: A
Systematic Review ..................................................................................................... 71
Preamble to Paper ................................................................................................... 71
Paper 2 .................................................................................................................... 71
Chapter 7: Rationale and Aims of Study Two ........................................................... 79
Rationale of Study Two .......................................................................................... 79
Aims and Hypotheses of Study Two ...................................................................... 79
Paper 3: Self-Regulation of Older Drivers by Cognitive Status: Discrepancy
between Driver and Passenger Reports .................................................................. 80
Preamble to Paper ................................................................................................... 80
Paper 3 .................................................................................................................... 80
Chapter 8: Prerequisites for Driving Cessation: Self-Reported and Passenger
Reported Factors ....................................................................................................... 110
Introduction ........................................................................................................... 110
Driving Cessation ................................................................................................. 110
Method .................................................................................................................. 111
Approach and Analysis ......................................................................................... 114
Results................................................................................................................... 114
Decline in health or functional abilities. ........................................................... 117
Assessment of road safety risk. ......................................................................... 118
Self-efficacy beliefs. ......................................................................................... 120
External attribution and reliance on others. ...................................................... 120
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Discrepancy between driver and passenger responses. ..................................... 121
Perspectives of drivers with cognitive impairment compared to those without.
........................................................................................................................... 121
Discussion ............................................................................................................. 122
Summary ............................................................................................................... 125
Chapter 9: General Discussion ................................................................................. 127
Introduction ........................................................................................................... 127
Summary of Key Findings .................................................................................... 128
Key findings from Study 1. ............................................................................... 128
Key findings from Study 2. ............................................................................... 129
Discussion of Findings with Respect to Theoretical Models of Driver Behaviour
.............................................................................................................................. 130
Differences between drivers with MCI and age-matched healthy adult drivers.
........................................................................................................................... 130
Self-regulation and self-monitoring. ................................................................. 131
Driving as an Everyday Competence Model. ................................................ 132
Summary: The Impact of MCI on Driver Performance and Driver Competence 133
Limitations and General Comments on the Methodology .................................... 133
Study 1 limitations. ........................................................................................... 134
Study population and sample size. ................................................................ 134
Study design. ................................................................................................. 135
Study strengths. ............................................................................................. 135
Study 2 limitations. ........................................................................................... 136
Driver self-report. .......................................................................................... 136
Obtaining information from collateral sources. ............................................ 137
Sample size and study population. ................................................................ 137
Measure of insight. ........................................................................................ 138
Measure of cognition. .................................................................................... 138
Implications for Research, Policy and Practice .................................................... 139
Implications for licensing authorities. ............................................................... 139
Implications for health professionals. ............................................................... 141
Implications for Australian senior drivers with cognitive impairment. ............ 143
Implications for research. .................................................................................. 144
Directions for Future Research ............................................................................. 145
Conclusions........................................................................................................... 147
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References ................................................................................................................ 148
APPENDIX A: THE PORTABLE SIMULATOR DRIVE EVENTS – STUDY 1 . 179
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LIST OF FIGURES
Figure 1: Information Processing Model of Driver Error……………………….24
Figure 2: Driving as an Everyday Competence Model………………………….52
Figure 3: Key components of the Driving as an Everyday Competence Model...131
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LIST OF TABLES
Table 1: Driver Characteristics……………………………………………………..51
Table 2: Passenger Characteristics…………………………………………………116
Table 3: Key Themes and Subthemes, Definitions and Exemplars Derived from the
Telephone Interview Data………………………………………………………….117

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Abstract
The assessment of fitness to drive in older individuals is controversial, with some
remaining safe and others presenting at a substantially increased risk. There is a need
to explore the nature of any deficits in driving performance in individuals with mild
cognitive impairment (MCI), whether they engage in self-regulatory behaviours, and
the extent to which they have insight into their driving behaviour. This thesis is
comprised of two experimental studies and a systematic literature review. The aim of
Study 1 was to establish brake profiles of older adults with and without mild
cognitive impairment at intersections using a portable driving simulator. An
experimental case-control study was conducted whereby 14 drivers with MCI and 14
age-matched healthy controls completed a simulator drive consisting of stop-sign
controlled and signal-controlled intersections. Findings partially supported the
hypothesis that compared to healthy older adult drivers, drivers with cognitive
impairment would engage in higher risk brake response patterns. Preliminary
evidence suggested that drivers with MCI may be less likely to stop at stop-sign
controlled, and possibly also at critical light change intersections. The systematic
literature review was conducted to identify existing literature on the topic of self-
regulation in older drivers with cognitive impairment. Current evidence suggests that
many drivers with cognitive impairment do self-regulate by restricting their driving
and avoiding certain driving situations.
The aim of Study 2 was to investigate the extent to which cognitive status
impacts on the decision to self-regulate driving behaviour and to determine whether
drivers who self-regulate demonstrate insight into a decline in their driving skills.
Older drivers were recruited from the general population in Victoria, Australia.
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Findings are presented with respect to cognitive status. Where available, passengers
provided an informant view of driver behaviour and an indicator of insight. The
findings are discussed in terms of implications for policy and practice regarding
older drivers and particularly those with MCI.