The featured paper is ‘Predictors of driving cessation in mild-to-moderate dementia’ by Herrmann and colleagues. This paper is by a group of Canadian Researchers and in the context of estimates of 500,000 Canadians with dementia by 2021. They also cite the American Academy of Neurology which provides clear guidelines for driving cessation using Clinical Dementia Ratings. The authors wanted to examine the factors which cause people to stop driving.
The researchers sampled 883 patients over the age of 60, living in the community with a diagnosis of dementia (DSM-IV criteria) and Global Deterioration Score of less than 5 indicating mild dementia. A number of cognitive measures were used including the Modified Mini-Mental State Examination and the Neuropsychiatric Inventory in a 3 year follow-up period. Test centres involved physicians from different disciplines – General Practice, psychiatry and neurology.
The average age of the sample was 77 years with a mean Mini-Mental State Examination Score of just under 22. 28.2% were still driving and 516 people were no longer drive. Of these people 4.7% had been involved in a ‘motor vehicle collision’ and 11.6% had their licenses revoked. A Cox survival analysis was performed to look at the factors associated with people remaining as drivers. At baseline nearly 3/4 of the drivers remaining were men and the factors that predicted cessation of driving included MMSE, GDS stage and behavioural problems (using the NPI). The items from the NPI which had the greatest significance were agitation/aggression (which reduced the likelihood of cessation), hallucinations and apathy (increased the likelihood of cessation). The authors suggest reasons for the NPI item associations with hallucinations being a marker of disease severity, apathy being likely to lead to cessation and aggression potentially leading to less direct communication about driving from others although each of these suggestions could form the basis for further research to assess their validity.
This is an important area of research and this paper provides some interesting results.
Herrmann N, Rapoport M, Sambrook R, Hebert R, McCracken P, Robillard A, for the Canadian Outcomes Study in Dementia (COSID) Investigators. CMAJ. 2006. 175(6). 591-595.
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