PROVIDENCE, RI A promising study from Rhode Island Hospital
demonstrated that cholinesterase inhibitors (ChEI), a type of
medication often prescribed for Alzheimer’s disease (AD), improved
some cognitive skills in patients with mild AD skills that are
necessary for driving. Findings from the study showed that after
being treated with a ChEI, AD patients improved in some
computerized tests of executive function and visual attention,
including a simulated driving task. The study is published in the
June 2010 edition of the Journal of Clinical
Psychopharmacology.
The study was led by Lori Daiello, PharmD, a research associate
at the Rhode Island Hospital Alzheimer’s Disease and Memory
Disorders Center (ADMDC). Daiello says, “Because many patients
receiving a diagnosis of AD continue to drive in its early stages,
it is critical that we assess driving safety among this population
and identify therapies that may improve driving abilities. ChEIs
are commonly prescribed for AD, yet little is known about how their
potential treatment effects might impact a driver’s skills.”
The researchers studied the performance of 24 outpatients with
newly-diagnosed, untreated, early stage AD using tests that
simulate typical situations encountered in on-road driving. The
subjects participated in computerized tests of visual attention
(visual search performed alone or in conjunction with simulated
driving) and executive function (maze navigation) both prior to
beginning treatment with a ChEI and again after three months of
therapy. The primary analysis consisted of comparing the test
performance of AD patients before starting ChEI treatment and after
three months of therapy. In a secondary cross-sectional analysis,
the subjects’ pre-ChEI computerized test performances were compared
to the abilities of a matched group of AD patients who had
performed the same computerized tests while receiving stable ChEI
therapy (i.e., greater than three months) during a prior study of
driving and dementia conducted at the Rhode Island Hospital
ADMDC.
The researchers report that ChEI treatment demonstrated
consistent effects in both the pre- and post-treatment comparison
as well as the cross-sectional comparisons. There were three key
findings:
- ChEI treatment was associated with improvement in the ability
to accurately maintain lane position during the simulated driving
task. This was noted in the pre- and post-ChEI treatment
comparison. It was also noted as an effect of ChEI user status when
the visual search task was performed without simulated driving in
the cross-sectional comparisons. - ChEI treatment was associated with improved target detection
accuracy in the visual search task and quicker visual search
response times in both the pre- and post-treatment comparison and
cross-sectional comparisons. - After ChEI treatment, subjects completed the computerized mazes
faster, although accuracy of completion was not affected.
Daiello, who is also an assistant professor of neurology
(research) at The Warren Alpert Medical School of Brown University,
says, “This study is the first of its kind to investigate how
treatment might impact cognitive domains critical to driving safety
in AD patients.” While relatively little is known about how ChEIs
affect cognitive functions in AD other than memory, these results
indicate an improvement in either attention processes or executive
control. The investigators note that while the results are
encouraging, this study lacked a direct measure of on-road driving
performance. These preliminary findings, however, warrant further
investigation. As Daiello says, “The results show an improvement in
the skills that will impact a patient’s ability to perform tasks
associated with safe driving.”
