Jan. 24, 2008 A new study by researchers at Rhode Island Hospital and Brown University finds that people with Alzheimer's Disease (AD) experienced more accidents and performed more poorly on road tests compared to drivers without cognitive impairment. While the study does confirm previous reports of potentially hazardous driving in persons with early AD, it also indicates that some individuals with very mild dementia can continue to drive safety for extended periods of time. The study included 128 individuals -- 84 with early AD and 44 age-matched control subjects without cognitive impairments. Drivers with early AD were enrolled in this study and followed every six months over two to three years.
Under the direction of principal investigator Brian Ott, M.D., director of the Alzheimer's Disease and Memory Disorders Center at Rhode Island Hospital and professor at The Warren Alpert Medical School of Brown University, the study looked at driving abilities through self-reports, family reports and a standardized road test.
The study results indicate that people with early AD experienced more accidents and performed more poorly on road tests when compared to participants without cognitive impairments. "We also found that people with what is defined as mild dementia were significantly more like to fail a road test than those defined with very mild dementia."
Ott says, "Our findings showed that people with mild dementia were nearly four times more likely to fail a road test than those with very mild dementia, indicating that people with very mild dementia may be able to drive safely for longer periods of time."
Ott notes, "It is clear, however, that driving ability declines fairly rapidly among patients with dementia, and therefore, regular follow-up assessments are warranted in these people with very mild dementia." Currently, the American Academy of Neurology Guideline on Risk of Driving and Alzheimer's Disease recommends a reassessment every six months for those patients diagnosed with very mild dementia who continue to drive.
The study also found increased age as well as lower education can impact driving abilities. Ott comments, "The odds of failing a road test increased by about six percent for every year exceeding the age of 75." The study found that drivers who lagged behind the average education experience within the study group were likely to fail a road test; failure was 10 percent more likely for each year in which they lagged behind the average education experience of 14 years.
Of interest, the frequency of motor vehicle accidents in the AD drivers declined during the study. Overall, Ott says, "The results suggest that a regular driving assessment program may actually reduce the frequency of motor vehicle accidents in drivers with mild dementia by increasing awareness among the driver and caregivers. This, however, may also result in premature termination of driving privileges for some persons with dementia." The researchers note that this is a major challenge facing clinicians: to develop valid and reliable office screening tools, which can assist the clinician with making driving assessment referrals and recommendations regarding driving safety for those with early AD.
The study is published in the January 23 edition of Neurology, the medical journal of the American Academy of Neurology.
The study was funded by a grant from the National Institute on Aging. The researchers recently announced the grant has been renewed to fund the study for another four years.
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