Differential Poststroke Motor Recovery in an Arm Versus Hand Muscle in the Absence of Motor Evoked Potentials.

The sample was modest, with 45 adults, and participants were mostly mildly or moderately impaired, so results may not apply to severely impaired patients. Measurements were obtained in only 67% to 87% of subjects at each time point, and some analyses used small groups, such as 4 finger-muscle cases and 8 biceps cases with persistent absent motor-evoked potentials. Only two muscles were studied, the first dorsal interosseous and biceps, so they may not represent all hand or arm muscles. Strength testing and Fugl-Meyer tasks were not identically matched across muscles and segments; finger dynamometry may require isolated finger movement, while arm Fugl-Meyer requires interjoint coordination. People with aphasia were excluded, which reduced left-hemisphere stroke representation. The study did not test any rehabilitation intervention, so it cannot show that a treatment changes recovery. The proposed role of alternative pathways, such as the reticulospinal tract, was not directly measured.

The authors declared no potential conflicts of interest. The article is listed as supported by NIH extramural and non-U.S. government funding.

Do not conclude that absent motor-evoked potentials mean the whole arm will not recover. In this study, the elbow flexor could still contract and recover strength without motor-evoked potentials, but the finger muscle and standardized arm-hand coordination scores remained impaired. The study was observational and did not test any treatment.