JMIR Publications

ABSTRACT

Background:

Dementia has an impact on the physical activities performed daily in a social context. Sleeping and resting in general is also affected by dementia. Monitoring techniques based on miniaturized wearable sensors and on sensorized environments allow to have actigraphic recordings and location trackings. The availability of contemporaneous physical activities profile let to quantify, in the social actigraphy approach, the level of correlation between individuals living in the same environment.

Objective:

The present study has two main objectives: 1) to define a methodology for actigraphic recordings, based on wearable accelerometers, and on location tracking, based on Bluetooth wearable technology, and to apply it in a well-defined social context, a long-term care residential unit for people with dementia; 2) to quantify test-retest reliability of the indexes obtained by the monitoring methodology.

Methods:

Persons with dementia living in the long-term care unit have been equipped with miniaturized wearable sensors, an accelerometer at their dominant wrist and a Bluetooth beacon at their ankle, for seven days. The raw recordings allowed for computing indexes related to physical activity intensities, to occurrence of walking bouts, to efficiency of sleep and waking phases, to social interactions between individuals, to locations preferably occupied. The seven-day session was repeated at short (three weeks) and long (three months) terms in order to quantify test-retest reliability of the indexes.

Results:

Twenty-five persons with dementia were enrolled, four of them dropped out and valid data were obtained, in the different sessions, from 19 to 21 individuals of the recruited group. Control data from ten age-matched healthy subjects were derived from published datasets. As a group, compared with age-matched healthy subjects, persons with dementia showed a comparable duration of phases of no activity and of light activity (energy cost lower than 3 METs), a relevantly lower duration (-84.3 %) of phases of moderate activity (energy cost ranging from 3 to 6 METs) and substantial absence (-100 %) of phases of vigorous activity (larger than 6 METs); moreover day time and night time were characterised by comparable wake and sleep, respectively, efficiency; finally, as to the social interactions, persons with dementia showed a lower correlation of their motor activity profiles (-53.1 %). The test retest reliability was excellent for physical activity indexes (ICCs ranging from 0.76 to 0.98), good for social indexes (0.65-0.67), excellent for sleep/wake efficiency (0.74-0.89) and fair for location tracking indexes (0.37-0.78).

Conclusions:

The considered methodology, particularly for what concerns the part based on accelerometry, proved to be feasible, informative and with a good to excellent test-retest reliability. Interestingly, the methodology clearly identified behaviours, such as wandering, in a minority of individuals inside the study group of persons with dementia, thus supporting a possible clinical use of the methodology.