Influences of upper limb orthosis on trunk muscle activity during static and dynamic sitting tasks for hemiparetic...

We aimed to clarify the immediate effect of wearing the Omo Neurexa upper limb suspended orthosis (Ottobock Japan, Tokyo, Japan) on trunk muscle activity during seated tasks.

Fifteen participants with upper limb hemiparesis were included. Surface electromyography of the thoracic and lumbar erector spinae and the external oblique muscles was performed. All participants performed static sitting, repetitive lateral reaching, and maximum lateral reaching tasks with or without the orthosis. The paired t-test was performed to compare the trunk muscle activity with and without the orthosis.

During static sitting, the activity of the thoracic and lumbar erector spinae muscles on the non-paretic side was significantly greater with the orthosis than without it (p = 0.025 and p = 0.047, respectively). The time required to complete five repetitive lateral reaching was significantly shorter with the orthosis than without it (p = 0.030). However, the orthosis did not affect during f repetitive lateral reaching and maximum lateral reaching task.

The upper limb orthosis may influence the activity of the trunk muscles of patients who had had a stroke during static sitting and improve the sitting reaching performance. Our results suggest that the effects of upper limb orthoses on trunk muscle and sitting performance should be further explored for the treatment of sitting disabilities after hemiparetic stroke. (University Hospital Medical Information Network Clinical Trials Registry number: UMIN 000044629).