Investigators identified associations between several distance and area-related life-space measures with TUG performance, not NIHSS or modified Rankin scales scores.
Findings from the prospective, observational MOBITEC-Stroke cohort study showed that the easy-to-assess timed up and go (TUG) performance is positively associated with life space 3 months after stroke. Life space is defined as the spatial extent in which a person moves within a specified period of time.
Led by Roland Rossler, PhD, head of the Basel Mobility Center, University of Basel, MOBITEC-Stroke was an observational study in which clinical evaluation and mobility measurements were performed at 3, 6, 9, and 12 months after ischemic stroke. This specific analysis focused on outcomes at 3 months. At each visit, a 4-h battery of clinical assessments, functional tests, and questionnaires were performed. Life space was assessed by a small portable tracking device for 7 consecutive days and by self-report, using the Life-Space Assessment (LSA).
The LSA measures the extent of an individual’s movement within the past 4 weeks, categorized into 5 spatial levels, ranging from the participant’s bedroom to places outside the participants’ hometown. Investigators used the TUG test as a general measure of physical function, with total time in seconds from standing up to sitting down as the main outcome. Stroke severity, using National Institutes of Health Stroke Scale (NIHSS) and level of functional independence, assessed through modified Rankin Scale (mRS) were also evaluated by a physician.
Overall, the analysis included 41 poststroke patients who had data collection take place 90.5 days, on average, post stroke. Coming into the trial, the cohort had a NIHSS score of 1.76 (standard deviation [SD], 1.68). Among those with available GNSS data (n = 41) and those for whom no valid GNSS data was available (n = 17), there were no statistical differences in any of the demographic, clinical, and functional mobility outcomes assessed (P >.14).
On univariable regression models, patients performance on TUG was positively associated with the LSA questionnaire, maximum distance from home, convex hull area, perimeter of the convex hull area, and the standard ellipse area, with P values that ranged between 0.003 and 0.018. There was no significant association between life-space measures and the NIHSS or mRS; however, investigators did report borderline associations with between the mRS and standard ellipse area (P = 0.053).
"The observed higher values in life space (i.e., objectively measured maximal distance from home and area-based measures) in participants with a better physical function (i.e., better TUG performance) appear to be reasonable based on findings reported for questionnaire-based life-space assessments in previous studies in patients with stroke,” Rossler et al wrote. "The ability to get up from a chair and walk is an essential component of being able to move within the life space. Physical function could be seen as a pre-requisite for the resulting life space."
To the authors knowledge, this was the first study investigating life space of patients with stroke using both the LSA questionnaire and a GNSS-based assessment. Following the univariable models, the multivariable regression analysis showed additional positive associations with TUG performance. These included maximum distance from home, the convex hull area, the perimeter of the convex hull area, and the standard ellipse area. Borderline associations were found for TUG performance and the LSA and the daily distance covered during the week. Similar to the univariable model, there was no evidence for an association between any life-space measure and the NIHSS or mRS.
In terms of strengths of the study, the authors wrote, “We performed our study 3 months after the stroke, a time point commonly used to evaluate stroke outcome. Our cohort of ambulatory patients with stroke was treated at a comprehensive stroke care center, integrating acute stroke treatment at the stroke center of the University Hospital Basel and the Neurorehabilitation Center, Felix Platter, within the Stroke Treatment Chain Basel."