DEVIATION FROM TYPICAL PATHS AS A MEASURE OF INTRAINDIVIDUAL VARIATION IN LIFESPACE. (16th November 2018)

• Record Type: Journal Article
• Authors: Nielsen, K; Mejia, S; Gonzalez, R; Carmichael, A
• Is Part Of: Innovation in aging. Volume 2(2018)Supplement 1
• Page Start: 915
• Page End: 915
• Publication Date: 2018-11-16
• Subjects: Aging -- Periodicals; Gerontology -- Periodicals; 612.67
• DOI: 10.1093/geroni/igy031.3405
• Languages: English
• ISSNs: 2399-5300

Abstract

Abstract: Lifespace is typically measured using a self-report questionnaire covering general areas visited over the past 4 weeks (Peel et al., 2005). However, this standard measure does not align with questions about how lifespace ebbs and flows in concert with daily experiences. Thus, methods to quantify perturbations of lifespace at faster timescales are needed. GPS and similar location tracking technologies allow for passive collection of rich data concerning day-to-day travel patterns. While many possible measures can be computed from such location data, we highlight deviation from a typical path as a relevant, dynamic aspect of lifespace across the lifespan. Derivation of this measure involves a two-step procedure. First, we use principal curves to fit one or more paths and estimate the noise in the latitude-longitude paths. Then, we compute the distance of each point from the path. These distance measures can be further summarized to match the research question - for example, a daily average deviation from typical path - and used in additional analyses such as growth curve models. We demonstrate the utility of this method using location data from cell phones of 10 community-dwelling women age 40–65 with moderate to severe bladder incontinence. We anticipate that these women are at risk of lifespace depletion, particularly when their bladder management plan fails. We find that employment, bladder leaks, and trust in their bladder management product all impact estimates of typical daily paths and deviations. This suggests that both inter- and intra-individual patterns in lifespace can be assessed using this technique.