Integration of wearable devices into regulated clinical trials for the assessment of cognition and function is a topic of interest. Researchers reported preliminary findings from an ongoing study designed to assess compliance, ease of use, reliability, and sensitivity of two industry-grade wearable devices for the real-time capture of gait and actigraphy measures in 100 older adults with and without subjective cognitive decline. The results were presented at the 13th Clinical Trials on Alzheimer’s Disease Congress 2020.
The study included 38 adults (aged 55 years and older), including 26 healthy controls and 12 individuals with subjective cognitive decline (SCD). Individuals were categorized as having SCD based on total scores of ≥4 on the Cognitive Functional Instrument. During visit one, participants were fitted with the Empatica E2 wrist-worn device that offers continuous measurement of motor activity (i.e., actigraphy), galvanic skin response, and sleep, as well as a pair of fitted Emoticon wireless shoe insoles for the collection of gait data.
Participants completed four standard laboratory-based mobility tests, including the timed 25-foot walk, a dual task timed 25-foot walk, Timed Up and Go, and 500-foot walk. Cognition and functioning were assessed using the Brief Assessment of Cognition (BAC), the Mini-Mental State Examination (MMSE), and the Virtual Reality Functional Capacity Assessment Test (VRFCAT). At the completion of the first visit, participants were sent home with the devices. After one week of continuous at-home data collection patients returned for a second visit, during which they repeated mobility and function assessments.
Participants with SCD performed significantly worse on the BAC (P<0.05 for tests of episodic verbal memory, working memory, processing speed, executive functions, and verbal fluency) and VRFCAT (P<0.05 for both completion time and errors), indicating objective impairments in this population.
Per data via the Emoticon insoles, those with SCD exhibited impaired gait parameters, including significantly prolonged mean stance duration and double support time, longer cycle time, and slower cadence on most laboratory-based assessments of mobility. In the combined sample, several gait measures were significantly correlated with functional capacity, such that reduced gait efficiency was associated with lower performance on the VRFCAT. Double support time (i.e., time spent with weight on both legs during walking) was correlated positively with VRFCAT completion time (P<0.05), as was length and variability in single leg stance duration during walking (P<0.05). Similar correlations were present for BAC (P<0.05).
For the Empatica device, compliance rates during the home phase were significantly lower for individuals with SCD (average of 13.65 hours of usable data/day) than controls (20.16 hours/day; P=0.01). Eight individuals with SCD and 25 controls met the predefined compliance requirement by wearing the devices a minimum of 10 hours for three or more days. Although there were no between-group differences in actigraphy during laboratory assessments, there were strong positive correlations between performance-based cognition and function and measures of daily activity/movement collected between study visits. Average waking activity level was positively correlated with BAC verbal fluency (P<0.001), verbal list learning (P<0.05), symbol coding (P<0.05), MMSE (P<0.05), and VRFCAT completion time (P<0.05).
“Challenges to integration in large-scale trials include ongoing support for users who may struggle with compliance due to cognitive impairment and lack of familiarity with wearable devices,” the researchers noted.
Presentation: P057: Real-time capture of gait and actigraphy using industry-grade wearable devices in older adults with and without subjective cognitive decline: Preliminary compliance, sensitivity, and correlations with cognition. Presented at the 13th Clinical Trials on Alzheimer’s Disease Congress 2020, Nov. 4-7, 2020.