Paretic upper extremity movement gains are retained 3 months after training with an electrical stimulation neuroprosthesis

Objective: To determine retention of upper extremity (UE) motor changes 3 months after participation in a regimen in which subjects with moderate UE hemiparesis engaged in repetitive task-specific training using an electrical stimulation neuroprosthesis (ESN).

Design: Prospective, blinded, cohort, pre-post study.

Setting: Outpatient rehabilitation hospital.

Participants: Individuals (N=24) in the chronic stage of stroke exhibiting stable UE hemiparesis (11 men; mean age, 57.9±9.5y; age range, 39-75y; mean time since stroke at time of repetitive task-specific practice [RTP] using ESN intervention start, 36.7mo; range of onset, 7-162mo).

Intervention: As part of a larger trial, subjects had been randomly assigned to receive an 8-week regimen comprised of RTP on valued activities using the ESN. This observational study assessed this single group's paretic UE motor levels immediately after, and 3 months after, the intervention.

Main outcome measures: The Fugl-Meyer (FM) assessment of sensorimotor impairment, the Action Research Arm Test (ARAT), the Arm Motor Ability Test (AMAT), and the Box and Block Test (BBT).

Results: None of the scores significantly changed from the period directly after intervention to the test 3-months follow-up (FM: t=1.64; ARAT: t=2.17; AMAT: t=.76, .92, and 1.01 for the functional ability, quality of movement, and time scales, respectively; BBT: t=.36; adjusted t critical value to reject the null [t(crit)]=2.90, 2-tailed α=.008 to preserve experiment-wise error rate of .05).

Conclusions: Subjects exhibited no changes in the various functional tests, indicating that changes in paretic UE movement realized through RTP using ESN appear to be retained 3 months after the intervention has concluded. This was the first study to our knowledge to examine the longer-term effects of RTP using an ESN in any population.