UNSTRUCTURED
Circadian rhythms of social activity constitute important temporal markers of the individual’s overall social dynamic and offer relevant opportunities in a large variety of applications including health monitoring. Indeed, analyzing circadian rhythms of social activity can help in monitoring the elderly, disabled, and chronically ill person at home by supervising their persistence through time, as well as their synchronization regarding how the individual acts and reacts with his social network across the day. Recent works have convincingly demonstrated the ability of measuring such rhythms on a digital way by the use of new technologies and the exploitation of their generated data. In particular, studies focusing on phone call detail records (CDRs) datasets have provided relevant results for exhibiting persistent circadian rhythms of phone call activity in young healthy adults. However, whether and how persistence and synchronization of circadian rhythms of phone telecommunication activity could also be observed in older adults still remains unclear.
The present paper is specifically designed to address this issue. To this end, we use a longitudinal 12-successive-month dataset that combines CDRs and questionnaire data of 21 volunteers older than 65 years. In this study, we use CDRs from which we operate four specific telecommunication parameters: (1) recipient (alter), (2) time, (3) duration and (4) direction of phone call. We specifically focus on two issues: (1) the existence of persistent daily rhythms in the older individual regarding his outgoing and incoming phone call activity, and (2) the existence of synchronization in the way the individual phones and responds to phone calls across the day. At individual level, our results demonstrate, for outgoing and incoming phone calls separately, that older adults do present persistent circadian rhythms of phone call activity. Then, we point towards these outgoing and incoming rhythms are also synchronized together. Indeed, despite the existence of some differences in their features, the overall distribution of the outgoing and incoming phone calls’ ratios across the day belong to the same family law at individual level. Interestingly, the present findings suggest that combining outgoing and incoming phone calls together without distinguishing their direction in CDRs analysis also can produce persistent circadian patterns of phone call activity in our older population. The significance and limitations of this study are discussed and a future research direction is proposed.