Risk factors for falls in community-dwelling patients with Alzheimer's disease and dementia with Lewy bodies: walking with visuocognitive impairment may cause a fall.

Background/aims: To identify risk factors for falls in community-dwelling patients with Alzheimer's disease (AD) and dementia with Lewy bodies (DLB).

Patients: 78 consecutive patients (51 AD, 27 DLB) were recruited from the Niigata Rehabilitation Hospital memory clinic.

Methods: We assessed the number of falls each patient had had in the previous 4 months. The data for DLB patients without motor parkinsonism were analyzed both as part of the whole DLB group and separately to determine the effect of parkinsonism alone on falls.

Results: Of 78 patients, 17 (21.8%) reported at least 1 fall during the period. A diagnosis of DLB, visual hallucinations, parkinsonism and cognitive fluctuation were significant predictors, but none of them was significant in the stepwise multivariate analysis. After excluding patients with parkinsonism, the use of hypnotics-anxiolytics and a worse score on the constructional task were significant and independent predictors of falling.

Conclusion: Parkinsonism was a major risk factor for falls. When AD or DLB patients walk with incongruent visual information, they may increase their postural sway or instability, because of their executive dysfunction. If elementary and/or higher-order visuocognitive impairment in AD or DLB patients alters visual information sufficiently, they may fall when walking.