Measuring Physical Behavior after Stroke : Sedentary behavior, body postures & movements, and arm use

The primary aim of this thesis was to investigate two methodological aspects of measuring physical behavior from the perspective of stroke rehabilitation. The methodological aspects were: 1) the effect of applying different operationalizations of the construct to be measured, and 2) the validity of a measurement device. These aspects were investigated with respect to three components of physical behavior: sedentary behavior, body postures & movements, and arm use. Another aim was to apply physical behavior monitoring to describe daily-life arm use in people after stroke. It was found that different operationalizations of sedentary behavior had a clear effect on the outcomes related to the total amount of sedentary time and the way sedentary time accumulates in bouts, in healthy people and in people after stroke. In both groups, the differences were not only significant but also large enough to acknowledge differences between the different operationalizations. Next, we found that the Activ8 Physical Activity Monitor was sufficiently valid to detect body postures & movements in people after stroke. The Activ8 Arm Use was developed and proved to be sufficiently valid to measure arm use during lying/sitting and standing in people after stroke. Therefore, both these activity monitors can be used to measure components of physical behavior in stroke rehabilitation. The results of using the Activ8-AUM in people after stroke showed that, 3 weeks after the stroke, the arm use ratio was low, i.e. the arms were used in a non-symmetrical way and with low use of the affected arm. During the first 26 weeks after the stroke, although the arm use ratio increased it remained significantly lower than the ratio in healthy people, as reported by others. Moreover, both the arm use ratio and its increase showed considerable variability between participants. The arm use ratio seems to be non-linearly related with arm function, because the positive relation between arm use and arm function was more clearly observed at higher levels of arm function

Development and validation of a clinically applicable ARM use monitor for people after stroke

Objective: To develop and validate a clinically applicable and easy-to-use accelerometry-based device to measure arm use in people after stroke; the Ac-tiv8 arm use monitor (Activ8-AUM). Design: Development and validation study. Patients: A total of 25 people at different stages of rehabilitation after stroke were included in this study. Methods: The Activ8-AUM consists of 3 single-sensor Activ8s: one on the unaffected thigh and one on each wrist. Arm use was calculated by combining movement intensity of the arms with data from body posture and movements on the leg sensor. Data were divided into 2 sets: one for determining situation-specific movement intensity thresholds for arm use, and the other to validate the Activ8-AUM using video recordings. Results: Overall agreement between the Activ8-AUM and video recordings was 75%, sensitivity was 73% and specificity was 77%. Agreement between the different categories of arm use ranged from 42% to 93% for the affected arm and from 24% to 82% for the unaffected arm. Conclusion: By combining the movement intensity threshold with body posture and movements, good agreement was reached between the Activ8-AUM and video recordings. This result, together with the easy-to-use configuration, makes the Activ8-AUM a promising device to measure arm use in people after stroke

Effect of different operationalizations of sedentary behavior in people with chronic stroke

Purpose: Sedentary behavior is common in people with stroke and has devastating impact on their health. Quantifying it is important to provide people with stroke with adequate physical behavior recommendations. Sedentary behavior can be quantified in terms of posture (sitting) or intensity (low energy expenditure). We compared the effect of different operationalizations of sedentary behavior on sedentary behavior outcomes (total time; way of accumulation) in people with stroke. Methods: Sedentary behavior was analyzed in 44 people with chronic stroke with an activity monitor that measured both body postures and movement intensity. It was operationalized as: (1) combining postural and intensity data; (2) using only postural data; (3) using only intensity data. For each operationalization, we quantified a set of outcomes. Repeated measures ANOVA and Bland–Altman plots were used to compare the operationalizations. Results: All sedentary behavior outcomes differed significantly between all operationalizations (p < 0.01). Bland–Altman plots showed large limits of agreement for all outcomes, showing large individual differences between operationalizations. Conclusions: Although it was neither possible nor our aim to investigate the validity of the two-component definition of sedentary behavior, our study shows that the type of operationalization of sedentary behavior si

The Accuracy of the Detection of Body Postures and Movements Using a Physical Activity Monitor in People after a Stroke

Background: In stroke rehabilitation not only are the levels of physical activity important, but body postures and movements performed during one&rsquo;s daily-life are also important. This information is provided by a new one-sensor accelerometer that is commercially available, low-cost, and user-friendly. The present study examines the accuracy of this activity monitor (Activ8) in detecting several classes of body postures and movements in people after a stroke. Methods: Twenty-five people after a stroke participated in an activity protocol with either basic activities or daily-life activities performed in a laboratory and/or at home. Participants wore an Activ8 on their less-affected thigh. The primary outcome was the difference in registered time for the merged class &ldquo;upright position&rdquo; (standing/walking/running) between the Activ8 and the video recording (the reference method). Secondary analyses focused on classes other than &ldquo;upright position&rdquo;. Results: The Activ8 underestimated the merged class &ldquo;upright position&rdquo; by 3.8% (775 s). The secondary analyses showed an overestimation of &ldquo;lying/sitting&rdquo; (4.5% (569 s)) and of &ldquo;cycling&rdquo; (6.5% (206 s)). The differences were lowest for basic activities in the laboratory and highest for daily-life activities at home. Conclusions: The Activ8 is sufficiently accurate in detecting different classes of body postures and movements of people after a stroke during basic activities and daily-life activities in a laboratory and/or at home

Objectively measured arm use in daily life improves during the first 6 months poststroke: a longitudinal observational cohort study

Background: It is unclear how arm use in daily life changes after stroke since studies investigating the change in arm use poststroke are scarce. The aim of this study was to investigate the change in arm use during the first six months poststroke. Secondary aim was to compare arm use changes between arm recovery clusters. Methods: Arm use was measured during week 3, 12, and 26 poststroke with accelerometers on the wrists and the nonaffected leg. Outcomes were the amount of affected and nonaffected arm use during sitting and standing per day and per sit/stand hour, and the daily ratio between arms. Arm function was measured with the Fugl-Meyer Upper Extremity Scale to identify recovery clusters (poor/moderate/excellent). Generalized estimating equations compared arm use outcomes between time points and between recovery clusters. Results: Thirty-three stroke patients participated. Affected arm use per day increased between week 3 and 12 (30 %; p = 0.04) and it increased per sit/stand hour between week 3–12 (31 %; p < 0.001) and between week 3 and 26 (48 %; p = 0.02). Nonaffected arm use per day decreased between week 3 and 12 (13 %; p < 0.001) and between week 3 and 26 (22 %; p < 0.001) and it decreased per sit/stand hour between week 3 and 26 (18 %; p = 0.003). The daily ratio increased between week 3 and 12 (43 %; p < 0.001) and between week 3 and 26 (95 %; p < 0.001). Changes in arm use did not differ significantly between recovery clusters (p = 0.11–0.62). Affected arm use was higher in the excellent recovery cluster (p < 0.001). Conclusions: Affected arm use and the ratio between arms increase during the first 26 weeks poststroke especially in patients with excellent arm recovery

Validation of a clinically feasible activity monitor which measures body postures and movements in adults with lower-limb amputation who wear a prosthesis

Purpose: A simple single-unit activity monitor (Activ8), which is based on a tri-axial accelerometer, measures specific body postures and movements, and has potential for research and clinical practice to monitor and optimize physical behavior of people with chronic conditions. However, the validity of the Activ8 in people with lower-limb amputation is unknown. Studying validity in this specific group is needed because they often have postures and movements that differ from the normal population, and which might affect validity. Therefore our study aimed to validate the Activ8 to measure body postures and movements in people with a lower-limb amputation. Methods: Thirty people with a unilateral lower-limb amputation and who are able to walk with a prosthesis completed two activity protocols in a simulated home setting: one with basic activities (only one posture or movement) and one with functional activities from daily living. Outcomes of the Activ8 (used in thigh-fixed position and pocket position) were compared to outcomes of video observation (the reference method). Primary analyses focused on the agreement in duration of merged measures of physical activity (walking, running, cycling, standing) and sedentary behavior (lying/sitting) with the Activ8 used in thigh-fixed position. Additional analyses included the detection of specific types of physical activity, the effects of amputation level and cause, and the validity of the Activ8 in pocket position. Results: Overall percentage time differences between Activ8 (thigh-fixed position) and video observation for merged measures of physical activity and sedentary behavior outcomes were −2.7% and 2.3%, respectively. These percentages were −1.6% and 1.3% for the basic protocol, and −3.9% and 3.6% for the functional protocol, respectively. For specific postures and movements, differences were larger (ranging from −12.6% to 7.1%). Conclusion: The Activ8 activity monitor has acceptable validity to measure physical activity and sedentary behavior in people with a unilateral lower-limb amputation