ADVANCE MOVEMENT PREPARATION IN HEMIPARETIC PATIENTS: ELECTROPHYSIOLOGICAL INDICE

Descriptors: motor preparation, hemiparesis, CNV Movement preparation in patients with left hand hemiparesis (n 5 26) was investigated using a response priming paradigm, and in addition compared to age-matched controls (n 5 26). In this experiment, trials with valid, neutral and no response cues were presented 1300 ms before the imperative stimulus. Behavioral results showed validity effects for the control and the patient group’s affected and unaffected hand. In addition, patients responded slower with both the affected and the unaffected hand compared to the control group. Analysis of CNV amplitude within the patient group revealed validity effects over the contralateral left hemisphere for the unaffected hand. Interestingly, similar validity effects where found for both hemispheres for the affected hand. This additional usage of the ipsilateral left hemisphere might reflect a greater effort required for movement preparation. A comparison between conditions of patient and control groups showed reduced CNV amplitude over central and centro-parietal right hemisphere for validly prepared trials of the unaffected hand compared to the control group’s right hand. This might suggest a reduced usage of the lesioned ipsilateral cortex side possibly reflecting reduced innervation after the acute phase of the stroke. The competition for resources in the left hemisphere between the affected and unaffected hand and the reduced usage of the right ipsilateral hemisphere for the unaffected hand might explain why patients are generally slower than controls in the task