title: Postural Transitions during Activities of Daily Living Could Identify Frailty Status: Application of Wearable Technology to Identify Frailty during Unsupervised Condition.
abstract: Impairment of physical function is a major indicator of frailty. Functional performance tests have been shown to be useful for identification of frailty in older adults. However, these tests are often not translatable into unsupervised and remote monitoring of frailty status at home and/or community settings.
  
  
  
  In this study, we explored daily postural transition quantified using a chest-worn wearable technology to identify frailty in community-dwelling older adults.
  
  
  
  Spontaneous daily physical activity was monitored over 24 h in 120 community-dwelling elderly (age: 78 ± 8 years) using an unobtrusive wearable sensor (PAMSys™, BioSensics LLC, Watertown, MA, USA). Participants were classified as non-frail and pre-frail/frail using Fried's criteria. A validated software package was used to identify body postures and postural transition between each independent postural activity such as sit-to-stand, stand-to-sit, stand-to-walk, and walk-to-stand. The transition from walking to sitting was further classified as quick sitting and cautious sitting based on presence/absence of a standing posture pause between sitting and walking. A general linear model univariate test was used for between-group comparison. Pearson's correlation was used to determine the association between sensor-derived parameters and age. Logistic regression model was used to identify independent predictors of frailty.
  
  
  
  According to Fried's criteria, 63% of participants were pre-frail/frail. The total number of postural transitions, stand-to-walk, and walk-to-stand were, respectively, 25.2, 30.2, and 30.6% lower in the pre-frail/frail group when compared to the non-frail group (p < 0.05, Cohen's d = 0.73-0.79). Furthermore, the ratio of cautious sitting was significantly higher by 6.2% in pre-frail/frail compared to non-frail (p = 0.025, Cohen's d = 0.22). Total number of postural transitions and the ratio of cautious sitting also showed significant negative and positive correlations with age, respectively (r = -0.51 and 0.29, p < 0.05). After applying a logistic regression model, among tested parameters, walk-to-stand (odds ratio [OR] = 0.997 p = 0.013), quick sitting (OR = 1.036, p = 0.05), and age (OR = 1.073, p = 0.016) were recognized as independent variables to identify frailty status.
  
  
  
  This study demonstrated that daily number of specific postural transitions such as walk-to-stand and quick sitting could be used for monitoring frailty status by unsupervised monitoring of daily physical activity. Further study is warranted to explore whether tracking the daily number of specific postural transitions is also sensitive to track change in the status of frailty over time.
authors.affiliation: Interdisciplinary Consortium on Advanced Motion Performance (iCAMP), Department of Surgery, College of Medicine, University of Arizona, Tucson, AZ, USA.
authors.forename: Saman
authors.initials: S
authors.lastname: Parvaneh
authors.forename: Jane
authors.initials: J
authors.lastname: Mohler
authors.forename: Nima
authors.initials: N
authors.lastname: Toosizadeh
authors.forename: Gurtej Singh
authors.initials: GS
authors.lastname: Grewal
authors.forename: Bijan
authors.initials: B
authors.lastname: Najafi
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D015444:Exercise / Q000502:physiology*; D005260:Female; D016330:Frail Elderly; D000073496:Frailty / Q000175:diagnosis / Q000503:physiopathology / Q000534:rehabilitation; D015577:Geriatric Assessment / Q000379:methods; D006801:Humans; D057187:Independent Living; D008297:Male; D018670:Monitoring, Ambulatory / Q000295:instrumentation / Q000379:methods; D009068:Movement / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D000076251:Wearable Electronic Devices
keywords: Cautious sitting; Frailty; Physical activity; Postural transition; Quick sitting; Telehealth; Walking to sitting; Wearable sensor