PRELIMINARY RESULTS FOR A TARGETED INTERVENTION FOR IMPROVING REACHING RANGE OF MOTION IN SEVERE HEMIPARETIC STROKE USING THE ARM

Abstract

Purpose/Hypothesis: Abnormal upper extremity coordination can be expressed in the form of atypical muscle synergies that result in limited and stereotypic movement patterns such that when an individual with hemiparetic stroke attempts to support the arm against gravity there is a strong coupling with elbow flexion. These movement constraints are functionally disabling. While quantification of stroke-related impairments such as abnormal shoulder/elbow torque coupling has been thoroughly described in our laboratory under isometric and dynamic conditions, only recently have striking advances in rehabilitation robotics enabled us to develop a rehabilitation protocol that specifically targets discoordination in a quantifiable and repeatable fashion. We have developed and are employing the Arm Coordination Training 3D Device (ACT3D). This report documents preliminary evidence supporting the efficacy of an impairment-specific dynamic strengthening protocol for a group of individuals with chronic stroke and was taken as part of a larger randomized controlled study. Number of Subjects: Six individuals with stroke were trained to actively support their arm while reaching to various outward targets over a period of eight weeks. Materials/Methods: The intervention was progressed by increasing the level of required active limb support or gravitational loading experienced by the participant during reaching repetitions as performance improved. Functional work area was evaluated pre-and post-intervention for ten different support levels. Pre- and post-intervention clinical assessments were also taken by a blinded physical therapist as secondary outcomes. Results: Consistent with our previous work, there was a significant effect of limb support level such that as subjects were required to support up to and beyond the weight of their limb, there was a concurrent reduction in available work area. Notably, there was a significant effect of session on work area. Following the intervention, work area significantly increased for all limb support levels. There were also related improvements in the clinical assessment battery. Conclusions: This preliminary data suggests that specifically targeting the abnormal joint torque coupling impairment is an effective strategy for improving reaching work area following hemiparetic stroke. Clinical Relevance: Following the completion of this study physical therapists will have new evidence supporting the application of an impairment-targeted intervention for individuals with chronic and severe hemiparetic stroke.