Recovery of an injured corticospinal tract during a critical period in a patient with intracerebral hemorrhage.

Most of the motor recovery in stroke occurs within 3 months after stroke onset and this period has been regarded as critical for motor recovery. Little is known about the motor recovery process during the critical period of stroke. We report on a patient with intracerebral hemorrhage (ICH) who showed recovery of an injured corticospinal tract (CST) during the critical period for motor recovery. A 43-year-old woman underwent conservative management for a spontaneous ICH in the right corona radiata and basal ganglia. She presented with complete left hemiplegia at the onset of ICH. She showed continuous and slow recovery, and consequently, she was able to flex her left fingers without gravity at 6 weeks after onset and extend the left fingers without gravity at 12 weeks. The 3- and 6-week DTTs showed that the right CST was discontinued around the hematoma. However, the 12-week DTT revealed that the right CST was originated from the right primary motor cortex and descended along the CST pathway. No motor evoked potential (MEP) was evoked from the right hemisphere on the 3- and 6-week TMS study. However, on the 12-week TMS study, an MEP which had the characteristics of the CST was evoked from the right hemisphere to the left abductor pollicis brevis muscle. Our results indicate that the injured right CST had been recovered between 6 weeks and 12 weeks after ICH onset. Consequently, we believe that this case demonstrated the recovery process of a severely injured CST during the critical period for motor recovery after ICH.