Photoplethysmography technology and its feature visualization for cognitive stimulation assessment

Therapeutic communication is recognized as an alternative cognitive stimulation for people with mental disorders. It is important to measure the effectiveness of such therapeutic treatments. In this paper, we present the use of photoplethysmography (PPG) technology to synchronize communication signals between the care-giver and people with dementia. To gain insights into the communication effect, the largest Lyapunov exponents are extracted from the PPG signals, which are then analyzed by multidimensional scaling to visualize the signal similarity/dissimilarity between the care-giver and participants. Experimental results show that the proposed approach is promising as a useful tool for visual assessment of the influence of the therapy over participants.