Actigraphy as a proxy biomarker for motoric agitation in Alzheimer disease

Background Agitation is an important symptom of dementia and is commonly assessed using clinician and/or caregiver rated scales. These scales are useful but they rely on a mixture of direct and indirect observations and therefore are subject to limited reliability and validity depending of factors such as staffing. Actigraphy is a tool to assess motoric activity, a core feature of agitation. There is a growing interest in using Actigraphy as a tool to diagnose and monitor agitation of dementia. We previously published a report demonstrating feasibility and a correlation between Actigraphy and informant‐based rating of physical agitation in a sample of hospital and nursing home patients with Alzheimer in moderate level of cognitive impairment from Kingston Ontario, Canada. Method This is an extension to our previous observational, cohort study now involving a sample of older adults with Alzheimer disease and agitation from London Ontario, Canada in hospital and nursing home with severe level of cognitive impairment. Measurements: Baseline characteristics included demographics, severity of cognitive impairment, medical comorbidity, and agitation symptoms assessed using CMAI and NPI. Actigraphy was measured over several continuous days. Results Twenty participants were enrolled (mean age=81.3/years, SD=7.97; Male=12; mean MMSE=6.3, SD=5.7; mean CMAI score=66.83, SD=10.79). Pearson correlation coefficient was explored between agitation and Actigraphy measures. We found that total CMAI scores correlated with 24‐hours Actigraphy data (r(18)= 51, p= .02), further analysis showed that only physical non‐aggressive agitation correlated with 24‐hours actigraphy measures (r(18)= 0.49, p=.03), this was mainly related to day‐time and evening‐time Actigraphy but not overnight. Conclusions Actigraphy was correlated significantly and moderately with informant‐based methods for measuring physical agitation in individuals with dementia and showed a temporal pattern of activity. Further studies are required to understand the application of Actigraphy as a biomarker for motoric agitation in this population.