Abstract
Background: Falls and fractures due to impaired balance in patients with
Alzheimer’s disease (AD) have an adverse effect on the clinical course of the disease.
Objective: To evaluate balance impairment in AD from the viewpoint of
vestibular functional impairment.
Methods: The subjects were 12 patients with AD, 12 dementia-free elderly
adults, and 12 younger adults. Vestibular function was assessed using a stepping test,
caloric nystagmus, and a visual suppression (VS) test.
Results: The stepping test was abnormal in 9 of the 12 patients in the AD
group. An abnormal stepping test was not associated with self-reported dizziness or
tendency to fall. Significant VS abnormalities were present in the AD group. The
suppression rate of VS was lower in AD patients with either a tendency to fall or
constructional apraxia than in AD patients without either. The velocity of the rapid phase
of caloric nystagmus before the VS test was similar in the AD group and the elderly
control group. Significant abnormalities of both caloric nystagmus and VS were not present
in either the elderly or the younger control groups.
Conclusion: AD could involve impairments in the vestibular control of
balance. The VS test is useful for assessing the tendency to fall in AD. Impairment of VS
in AD might arise from cerebral vestibular cortex impairment rather than comorbid
peripheral vestibular disorders.
