Use of the global positioning system to measure the out-of-home mobility of older adults with differing cognitive functioning

Cognitive impairment manifests in changed out-of-home mobility. Until recently, the assessment of outdoor mobility relied on the reports of family care-givers and institutional staff and used observational approaches, activity monitoring or behavioural checklists. This article presents data for 41 mildly demented, mildly cognitively impaired and healthy men and women aged 64-90 years in Tel-Aviv (Israel) who took part in an interdisciplinary project, SenTra, that is studying the outdoor activities of elderly people using advanced tracking technologies and that involves researchers from geography, social work, gerontology, psychology and medicine. The participants were tracked for 28 consecutive days using a location kit that combined a global positioning system (GPS) with radio frequency identification. The high-resolution spatial and temporal data enabled detailed analysis of the differences in the timing and distance of the participants' daily outdoor mobility patterns. It was found that the spatial range of the mobility of elderly people with cognitive impairment is severely restricted, with most out-of-home time spent in close proximity to their residences. We conclude that GPS is an advanced research tool able to understand out-of-home behaviour better than was possible with previous methods.