Article

Repetitive transcranial magnetic stimulation (rTMS) modulates central
neuropathic pain in some patients after stroke, but the mechanisms of action are
uncertain. The authors used diffusion tensor imaging (DTI) and
functional MRI (fMRI) to evaluate the integrity of the thalamocortical tract
(TCT) and the activation pattern of the pain network in 22 patients with
poststroke central pain. METHODS: Each patient underwent daily 10-Hz rTMS
sessions for 1000 pulses on 5 consecutive days over the hotspot for the first
dorsal interosseus muscle. Pain severity was monitored using the Visual Analogue
Scale (VAS). Mood was assessed by the Hamilton Depression Rating Scale. RESULTS:
Clinical data from all participants along with the DTI and fMRI findings from 10
patients were analyzed. VAS scores decreased significantly, if modestly,
following administration of rTMS in 14 responders, which lasted for 2 weeks after
the intervention. Regression analysis showed a significant correlation between
less initial depression and higher antalgic effect of rTMS. Integrity of the
superior TCT in the ipsilesional hemisphere showed significant correlation with
change of VAS score after rTMS. fMRI showed significantly decreased activity in
the secondary somatosensory cortex, insula, prefrontal cortex, and putamen in
rTMS responders, whereas no change was noted in nonresponders. CONCLUSION: . Mood
may affect the modest antinociceptive effects of rTMS that we found, which may be
mediated by the superior TCT through modulation of a distributed pain network.

Langue : ANGLAIS