Chronic cerebellar stimulation for cerebral palsy--five-year study.
Two hundred sixty-two patients were implanted with cerebellar stimulator systems since February 1974. Cerebral Palsy (CP) patients constituted 88% (230) of this series. The age range was 3 to 53 years with 70% under 20 years of age. Half the CP series were severely affected with the rest being moderately to mildly involved. Athetosis was present in 50%. The primary effect of CCS has been a lowering of spastic muscle tone in 90% of the patients. Improvements in control of immature reflexes such as startle response, head control, scissoring, balance and sitting occur in the first month. Athetosis progressively decreases to a 50% level. In the moderate mild CP group abilities improve over the first six months leading to better feeding, dressing, and ambulation with clearer speech and less drooling. After six months, 25 of 48 patients were out of wheelchairs, walking. A further 47 patients were ambulating better. No deaths from surgery. Five have died during the 5 years from other causes. Eleven patients (4%) have had infected systems. Equipment problems especially with malfunctioning radio receivers (40%) have served as blind controls--spasticity returning and abilities decreasing. Replacements with another receiver or with a totally implantable lithium powered pacemaker (May 1979) have lead to a return of benefits. Post-mortem findings indicate the low current levels (0.8 uC/sqcm) applied intermittently produced no appreciable damage to the cerebellar cortex.