Spinal Cord Stimulation in Multiple Sclerosis

Abstract

The changing methods of electrical stimulation of the spinal cord employed in patients with MS are described. The most recent innovation is that of epidural placement of electrodes for temporary and permanent stimulation.

The most favorable effects are modification of urinary dysfunction, voluntary motor dysfunction of limbs, pain, equilibratory and non-equilibratory coordinate dysfunction. Not all these changes occur in all patients and when a change occurs it varies from patient to patient. Persistence of effect may persist after stimulation is discontinued over variable periods, and this period is increased with increased duration of prior stimulation.

These experiences indicate it is possible to restore voluntary control, even integrated movement, in patients with MS. It is suggested that there may be an intrinsic pacemaker arrangement within the spinal cord which is modified by electrical stimulation.

There is increasing recognition of the importance of dendritic arborizations and bundles within the spinal cord and it is this type of anatomical arrangement which suggests the potential of sensory-motor computation at the spinal cord level.

The effect of electrical stimulation on the electrical activity of the spinal cord is discussed, and it is noted that the effect is non specific. However, the possibility exists that it may change polarization in areas of dendritic arborization wherein programs may reside for certain types of motor activity. Present information suggests cathodal stimulation may be better than bipolar stimulation.