Increase of cerebral blood flow and improvement of brain motor control following spinal cord stimulation in ischemic spastic hemiparesis.

Abstract

A 64-year-old man had an ischemic stroke in the left parietotemporal cortical-subcortical areas. He developed a severe right spastic hemiparesis and dysphasia. An angiographic study showed left internal carotid artery occlusion and right internal carotid artery stenosis. A right internal endoarteriectomy was performed without any clinical improvement. After 1 year the patient was a candidate for cervical spinal cord stimulation (SCS) for the treatment of his spastic hemiparesis. An epidural electrode (Medtronic Sigma 3483) was positioned at the cervical level, mediodorsal to the cord. Clinical and neurophysiological studies (surface polyelectromyography, PEMG, for evaluation of brain motor control) were performed before and after 7 days of SCS (0.2 ms, 80 c/s, intensity for paresthesiae, continuous mode). A transcranial Doppler (TCD) study of both middle cerebral arteries (MCA) at rest and during SCS was performed on two occasions. SCS was followed by improvement of voluntary movement, decrease of spasticity and better endurance. The clinical findings were confirmed by the PEMG recordings. TCD examination showed an increase of flow velocities on both the right MCA (+43%) and the left MCA (+130%) during SCS. Such a TCD pattern, suggesting an increase of cerebral blood flow (CBF) during SCS, was reproducible. This case confirms efficacy of SCS in the treatment of ischemic hemiparesis and the increase of CBF following cervical SCS in man. The marked increase of CBF, particularly evident on the ischemic side, may play a role in mediating the improvement of motor control in our patient together with a possible arousal of the so-called 'sleeping neurons' of the penumbra zone.