Automated Video Analysis of Handwashing Behavior as a Potential Marker of Cognitive Health in Older Adults

The identification of different stages of cognitive impairment can allow older adults to receive timely care and plan for the level of caregiving. People with existing diagnosis of cognitive impairment go through episodic phases of dementia requiring different levels of care at different times. Monitoring the cognitive status of existing patients is, thus, critical to deciding the level of care required by older adults. In this paper, we present a system to assess the cognitive status of older adults by monitoring a common activity of daily living, namely handwashing. Specifically, we extract features from handwashing trials of participants diagnosed with different levels of dementia ranging from cognitively intact to severe cognitive impairment, as assessed by the mini-mental state exam (MMSE). Based on videos of handwashing trials, we extract two classes of features: one characterizing the occupancy of different sink regions by the participant, and the other capturing the path tortuosity of the motion trajectory of participant's hands. We perform correlation analysis to assess univariate capacity of individual features to predict MMSE scores. To assess multivariate performance, we use machine learning methods to train models that predict the cognitive status (aware, mild, moderate, severe), as well as the MMSE scores. We present results demonstrating that features derived from hand washing behavior can be potential surrogate markers of a person's dementia, which can be instrumental in developing automated tools for continuously monitoring the cognitive status of older adults.