IMPASS
Research type
Research Study
Full title
Improving the assessment of driving safety in cognitive impairment
IRAS ID
264675
Contact name
Paul Donaghy
Contact email
Sponsor organisation
CNTW NHS Foundation Trust
Duration of Study in the UK
4 years, 0 months, 1 days
Research summary
Summary of Research
Most older people in Great Britain are current driving licence holders. As a result, many people with cognitive impairment (dementia or mild cognitive impairment) are drivers. Clinicians have a responsibility to advise patients regarding the impact of their cognitive impairment on driving, but there is little research evidence to support such advice.
The aim of this project is to develop a tool that can be used to classify drivers with cognitive impairment as ‘likely safe’, ‘likely unsafe’ and ‘uncertain (requires further assessment)’.
People with cognitive impairment that have been referred for a Driving Mobility assessment will be approached for participation in the study. Driving Mobility assessment includes an assessment of physical function, a screening assessment of visual function, cognitive assessment utilising a defined battery and an on-road driving assessment lasting between 45 minutes and an hour. Prior to this assessment, the PhD student will assess a range of clinical variables thought to be associated with driving safety during a home visit. The strongest predictors of Driving Mobility assessment outcome will be identified and included in a tool to help assess driving safety. This tool will then be tested versus a Driving Mobility assessment in an independent group.
If successful this tool will support clinicians to more accurately assess driving safety. This will ensure that steps are taken to maintain the safety of people with cognitive impairment and other road users when necessary and also prevent the distress caused by unnecessary curtailment of driving in those that are safe to drive.
Summary of Results
As people get older, many continue to drive. In the UK, about two-thirds of people over 70 still have a driving licence. However, dementia can affect memory, attention, vision, and decision-making—skills that are essential for safe driving. Clinicians are expected to advise patients with dementia about driving safety, but many feel uncertain about how best to do this.This research aimed to understand what information helps predict whether a person with memory or thinking problems can drive safely, and whether a simple tool could be developed to assist clinicians.
What the research did
The project had five parts:
1. Reviewed the existing evidence on what clinical tests or information may predict driving safety in people with dementia or mild cognitive impairment (MCI).
2. Interviewed clinicians working in memory services to understand how they currently make driving-related decisions and what support they need.
3. Analysed clinical data from people who had already completed an independent on-road driving assessment, to see which routine tests best distinguish safe from unsafe drivers.
4. Developed a simple decision aid tool based on the findings.
5. Tested this tool with a new group of participants and explored whether additional tests might better predict driving safety.What the research found
1. Evidence review
The review found that although thinking skills are linked to driving safety, current tests are not accurate enough on their own to reliably predict who is safe or unsafe. Some tests—like the Mini-Mental State Examination (MMSE) and Trail Making Tests—can help, but they should be used alongside professional judgement and guidelines.2. Clinician interviews
Clinicians reported:
• Difficulty raising the subject of driving with patients.
• Mismatched expectations between patients and clinicians.
• Uncertainty about what information to use.
• A strong desire for a simple, practical tool to support decisions.
• A need for better training on assessing driving safety.3. Clinical data analysis
Thirty-one people with MCI or dementia were included. Only two pieces of routine clinical information clearly helped distinguish safe from unsafe drivers:
• Age over 80
• A lower score on the visuospatial part of the ACE-III (a cognitive test)
Most other routine clinical measures—including medications, mood, functional assessments, or overall cognition—did not predict driving ability.4. Development of the clinical tool
A simple tool (scored 0–2) was created using the two predictors above.
In the original dataset, the tool seemed to work well—correctly identifying most low- and high-risk drivers.5. Testing the tool in a new group
When the tool was tested in a fresh group of participants, it did not work reliably. It failed to accurately identify unsafe drivers and could not be recommended for clinical use.
Some additional tests—such as reaction-time tasks and visuospatial maze tests—showed promise, but were not tested in a second independent group.What this means
• It remains very difficult to predict driving safety in people with mild dementia or MCI using routine clinical tests.
• Simple tools based on existing clinical information do not perform well enough to guide decisions.
• Instead of trying to predict who is safe, the focus should be on identifying who may need a specialist on-road driving assessment.
• Better training, clearer guidelines, and improved communication strategies are needed for clinicians.
• Newer, more sensitive tests (especially reaction-time and visuospatial tasks) may help in the future, but require further research.Conclusion
At present, the newly developed decision aid tool cannot replace the current approach of using a holistic clinical assessment and specialist advice when considering driving safety in people with dementia. More research is needed to find accurate and practical ways to support clinicians and patients with these challenging decisions.REC name
HSC REC B
REC reference
19/NI/0220
Date of REC Opinion
17 Dec 2019
REC opinion
Favourable Opinion