Self-directed arm therapy at home after stroke with a sensor-based virtual reality training system

Abstract

Background: The effect of rehabilitative training after stroke is dose-dependent. Out-patient rehabilitation training is often limited by transport logistics, financial resources and a lack of motivation/compliance. We studied the feasibility of an unsupervised arm therapy for self-directed rehabilitation therapy in patients' homes.

Methods: An open-label, single group study involving eleven patients with hemiparesis due to stroke (27 ± 31.5 months post-stroke) was conducted. The patients trained with an inertial measurement unit (IMU)-based virtual reality system (ArmeoSenso) in their homes for six weeks. The self-selected dose of training with ArmeoSenso was the principal outcome measure whereas the Fugl-Meyer Assessment of the upper extremity (FMA-UE), the Wolf Motor Function Test (WMFT) and IMU-derived kinematic metrics were used to assess arm function, training intensity and trunk movement. Repeated measures one-way ANOVAs were used to assess differences in training duration and clinical scores over time.

Results: All subjects were able to use the system independently in their homes and no safety issues were reported. Patients trained on 26.5 ± 11.5 days out of 42 days for a duration of 137 ± 120 min per week. The weekly training duration did not change over the course of six weeks (p = 0.146). The arm function of these patients improved significantly by 4.1 points (p = 0.003) in the FMA-UE. Changes in the WMFT were not significant (p = 0.552). ArmeoSenso based metrics showed an improvement in arm function, a high number of reaching movements (387 per session), and minimal compensatory movements of the trunk while training.

Conclusions: Self-directed home therapy with an IMU-based home therapy system is safe and can provide a high dose of rehabilitative therapy. The assessments integrated into the system allow daily therapy monitoring, difficulty adaptation and detection of maladaptive motor patterns such as trunk movements during reaching.

Trial registration: Unique identifier: NCT02098135 .

Keywords: Arm; Feasibility; Rehabilitation; Stroke; Video games; Virtual reality therapy.

Figures

Fig. 1

System Overview and Study Outline. a: Photograph of a healthy subject using ArmeoSenso. b: Screenshot of the pointing task assessment: the virtual upper- and lower arm and the trunk are displayed. The arm points to a target. c: Sequence of a training session. Before each training session, two automated assessments are performed. d: Study outline: The ArmeoSenso system is installed in the patient's home for six weeks. The patients are assessed clinically before the start, after three weeks, and after six weeks of training. Abbreviations: WMFT: Wolf Motor Function Test; FMA-UE: Fugl-Meyer Assessment Upper Extremity; NIHSS: National Institute of Health Stroke Scale. *system installation and patient instruction by a therapist

Fig. 2

System Usage: a-d: Each symbol represents one patient. a: Weekly training duration for weeks 1–6 and average weekly training duration for each patient. b: Training duration per session. c: Number of days with training. Horizontal lines indicate averages. d: Average weekly training duration in patients with low (<20 points) Fugl-Meyer Assessment Upper Extremity (FMA-UE) and intermediate to high (>20 points) FMA-UE score. * indicates significant differences in usage

Fig. 3

Arm Function Assessments: a-d: Each symbol represents one patient. a-c: Horizontal bar = average. a: Fugl-Meyer Assessment Upper Extremity (FMA-UE) shows significant improvement after six weeks of therapy. b-d: ArmeoSenso-based Assessments. In one instance, a patient did not use the system during a block of two weeks. Here, the previous value was carried forward. b: Arm Workspace Assessment. The workspace is reported as squares, i.e. relative units for the covered workspace and shows significant improvement after six weeks. c: Pointing Task Assessment. The average time to reach targets improves significantly. d: Significant correlation between clinical assessment (Fugl-Meyer assessment after 3 weeks of training) and ArmeoSenso assessment (time to reach target, average of training week 3–4, c)

Fig. 4

Trunk Movement during Pointing. Trunk rotation (a, b) and inclination (c, d) (two-weekly average) during pointing movements in the pointing task assessment for one specific target. For comparison, the values of 10 pointing movements performed with the unaffected limb are plotted (N = 8). b + d: To demonstrate the high inter-session variability of trunk rotation and inclination during pointing movements, a complete dataset of one patient (impaired side) is plotted for the same target. Error bars: standard deviation