Increased regional cerebral perfusion in contralateral motor and somatosensory areas after median nerve stimulation therapy

Abstract

To evaluate change in regional cerebral perfusion (rCBF) after median nerve stimulation (MNS) therapy in brain-damaged patients. Twelve brain-damaged patients received 12 courses of MNS. Technetium-99m-ethyl cysteinate diethylester (99mTc-ECD) SPECT was performed before and 4 weeks after MNS initiation. Clinical response was assessed by Glasglow coma scale or clinical improvement. 12 MNS patients were grouped as good responder (GR) (n = 6) and poor responder (PR) (n = 6) according to therapy response. Scan images were analyzed by Statistical Parametric Mapping 2 (SPM2). In the GR group, paired Student t test between the pre- and post-MNS images showed 2 activation clusters over the left frontal and parietal lobes, including regions of the precentral gyrus, middle frontal gyrus, superior frontal gyrus, subgyral, inferior parietal lobule, and postcentral gyms (corresponding to Brodmann areas 4, 6, and 40). In the PR group, paired Student t test did not show any activation clusters. Clusters with significant differences between the GR and PR groups shared no mutual voxels with those clusters having significant regional effects after MNS in the GR group. Median nerve stimulation enhanced the rCBF of the contralateral motor and somatosensory cortex, which is compatible with the few previous studies using other modalities.