Kinematic Changes in the Uninjured Limb After a Traumatic Brachial Plexus Injury

Abstract

Background: Traumatic brachial plexus injury (TBPI) typically causes sensory, motor and autonomic deficits of the affected upper limb. Recent studies have suggested that a unilateral TBPI can also affect the cortical representations associated to the uninjured limb.Objective: To investigate the kinematic features of the uninjured upper limb in participants with TBPI.Methods: Eleven participants with unilateral TBPI and twelve healthy controls matched in gender, age and anthropometric characteristics were recruited. Kinematic parameters collected from the index finger marker were measured while participants performed a free-endpoint whole-body reaching task and a cup-to-mouth task with the uninjured upper limb in a standing position.Results: For the whole-body reaching task, lower time to peak velocity (p = 0.01), lower peak of velocity (p = 0.003), greater movement duration (p = 0.04) and shorter trajectory length (p = 0.01) were observed in the TBPI group compared to the control group. For the cup-to-mouth task, only a lower time to peak velocity was found for the TBPI group compared to the control group (p = 0.02). Interestingly, no differences between groups were observed for the finger endpoint height parameter in either of the tasks. Taken together, these results suggest that TBPI leads to a higher cost for motor planning when it comes to movements of the uninjured limb as compared to healthy participants. This cost is even higher in a task with a greater postural balance challenge.Conclusion: This study expands the current knowledge on bilateral sensorimotor alterations after unilateral TBPI and should guide rehabilitation after a peripheral injury.

Upper limb joint coordination acts to preserve hand kinematics after a traumatic brachial plexus injury

“…Results revealed altered kinematics for MD, PV, TPV and TL. TBPI individuals also showed lower TPV values in a bring-a-cup-to-the-mouth task, pointing to a more controlled hand deceleration (Souza et al, 2021). The difference observed in the previous study is justified by the injured UL variability in the present study.…”

“…Only a small sample of participants was able to perform movements with the injured UL, and this taken together with the high variability in their data may have hidden some previous findings in the uninjured UL (Souza et al, 2021). Future analysis may be improved with a higher number of participants able to perform injured UL movements and by the categorization of the severity of the injury in kinematic analysis.…”

“…In Souza et al (2021), the uninjured UL kinematics was tested in a task involving trunk displacement.…”

“…Moreover, the alterations in the kinematics of the uninjured UL gives evidence for the inclusion of the uninjured UL in rehabilitation programs. The idea of a broad rehabilitation approach has already been suggested by previous studies (Souza et al, 2016(Souza et al, , 2021, which pointed to a rehabilitation program that included balance assessment and considered the uninjured UL for training…”

“…Likewise, the movement of injured UL in TBPI individuals could show a modified pattern of arm-forearm coordination combined with preservation of hand kinematic performance. Furthermore, as changes in the kinematics of the uninjured UL in TBPI have been previously reported (Souza et al, 2021), we also investigated the arm-forearm coordination and its relationship with the hand kinematics of this limb.…”