Circadian aspects of mobility-related behavior in patients with dementia: An exploratory analysis in acute geriatric psychiatry.

Abstract

Analyzing patients' mobility-related behavior may improve the assessment of motor behavior in dementia, however, few studies addressed circadian aspects of mobility. This cross-sectional explorative study analyzed the timing of peak mobility-related behavior, the prevalence of mobility-related sundowning and nocturnal mobility-related behavior and associated clinical characteristics in acute geriatric psychiatry. Mobility-related behavior of 73 patients (M: 81years) was measured over 48h using lower-back worn hybrid motion sensors. We derived the start of the 30-min period with peak gait activity (highest number of steps) for each day and the number of nocturnal steps taken from 10PM to 7AM. Professional caregiver ratings of the patients' motor behavior were conducted within the Neuropsychiatric Inventory (NPI). The mean start time of peak gait activity was 2:37PM, but large variations in timing were found (range: 3:25AM-9:30PM). Twenty-five patients (34%) were identified as "sundowners". Nocturnal mobility-related behavior was measured in 35 patients (53%), whereas professional caregivers assessed night-time disorders in only 19 patients (26%). Clinical characteristics of "sundowners" were not significantly different from other patients, except for lower doses of antipsychotics as compared to non-sundowners (M:1.6mg/day; p=0.015). The number of nocturnal steps was significantly associated to corresponding NPI ratings (Spearman's rho=0.4; p<0.001). Analyzing the timing of peak gait activity and nocturnal step-count seem to provide clinical applicable information on the circadian aspects of mobility-related behavior in acute geriatric psychiatry. Even though the clinical validity needs to be evaluated, objective information on the individual circadian aspects of mobility-related behavior could help to personalize treatment with benefits for patients and caregivers.