Affected arm use and cortical change in stroke patients exhibiting minimal hand movement

Abstract

Background and purpose: Conventional electrical stimulation modalities are limited by their lack of opportunities for motor learning and, consequently, their impact on function. Other rehabilitative regimens necessitate affected hand and wrist movement for patients to be included, making them implausible for most patients. In light of these challenges, the current study examined the efficacy of a repetitive task-specific training (RTP) regimen using an electrical stimulation neuroprosthesis in stroke patients exhibiting no affected wrist or hand movement.

Method: Eight chronic stroke patients (mean = 46.5 months) with moderately affected arm motor deficits participated in 30-minute therapy sessions occurring every weekday for 8 weeks. During the sessions, they wore the neuroprosthesis to enable performance of valued activities identified largely by the patients. To ensure transfer to their real-world environments, most sessions were home based, with the patients coming to the clinic for "tune-up" sessions (eg, adjusting the stimulation parameters, exercises, and/or fit of the device) twice every other week (a total of 8 clinical visits). Outcomes were evaluated using the Action Research Arm Test (ARAT) and the upper extremity section of the Fugl-Meyer Assessment (FM), the amount of use scale of the Motor Activity Log (MAL), and high-field functional magnetic resonance imaging (fMRI).

Results: Before the intervention, patients exhibited stable motor deficits. After the intervention, they exhibited ARAT and FM score increases (+2.85 and +2.2, respectively). Postintervention fMRI revealed significant increases in cortical activation, possibly brought about by markedly increased affected arm use patterns on the MAL (+0.97).

Conclusions: An affected arm RTP program incorporating NEURSTIM appears to increase affected arm use and elicit neural changes in more impaired patients. These factors may conspire to produce motor changes, although motor changes are smaller in this population than with less impaired patients. The program may act as a "bridge" to other promising regimens.