Article

Little is known about the motor recovery mechanisms via transcallosal or
tranpontine fibers in stroke patients. In the current study, an attempt was made
to demonstrate motor recovery via transcallosal and transpontine fibers in a
patient with intracerebral hemorrhage using diffusion tensor tractography and
transcranial magnetic stimulation. A 39-yr-old male patient presented with
complete weakness of the right extremities at the onset of a left midbrain
hemorrhage. His motor weakness had shown slow recovery for 4 mos to the point
that he was able to grasp and release using the right hand. Diffusion tensor
tractography and transcranial magnetic stimulation were performed at 2 wks and 4
mos after onset. Discontinuation of the left corticospinal tract below the left
midbrain was observed on the 2-wk diffusion tensor tractography and no motor
evoked potential was elicited in the right hand on the 2-wk transcranial magnetic
stimulation study. Four-month diffusion tensor tractography showed that the
discontinuation of the left corticospinal tract had not been restored; however, a
new neural pathway was observed, which originated from the left primary motor
cortex and descended to the left corticospinal tract at the pons through the
transcallosal and transpontine fibers. In the 4-mo transcranial magnetic
stimulation study, the latency of motor evoked potential obtained at the right
hand by stimulation of the left motor cortex was delayed by 9 msecs, compared
with the opposite motor evoked potential, which seems to be compatible with
transcallosal and transpontine conduction time. The results suggest that the
motor function of the affected extremities in this patient was recovered through
the transcallosal and transpontine fibers from the left motor cortex.

Langue : ANGLAIS