Instrumentation, working hypotheses, and clinical aspects of neurostimulation

Neural stimulation for spinal spasticity

The knowledge of neural plasticity is used to improve motor function of the spinal cord by chronic stimulation of the dorsal columns. We achieved this with an improvised technique. The electrodes are exteriorized and stimulated by using a Grass stimulator. Five paraplegic patients with different aetiologies causing their paraplegia were treated by this method, and the details are enumerated. Four had good improvement and relaxation was maintained for varying periods after cessation of the stimulation. Mode of action is discussed.

Use of chronic cerebellar stimulation for disorders of disinhibition

A review of the clinical results from 200 patients and the neurophysiological results from 42 patients suggests that chronic cerebellar stimulation (c.c.s.) can improve cerebral palsy and reduce intractable seizures. The therapeutic effects of stimulation of the cerebellar surface may not be due to activation of Purkinje cells. There is evidence that stimulation of brainstem structures, particularly the reticular formation, may be associated with thalamic inhibition; such effects would explain the clinical results of c.c.s. as well as the reduction in amplitude of reflexes, evoked potentials, and paroxysmal discharges in the electroencephalogram. This hypothesis would explain the prolonged, rebound, paradoxical, and cumulative effects of c.c.s. No clinical disturbance or significant tissue damage has resulted from c.c.s. over 5 years. The technique is an example of the therapeutic manipulation of inhibitory and disinhibitory mechanisms in the central nervous system.