Speech changes in cerebral-palsied patients after cerebellar stimulation

A quantitative study was made of the effects of focal cerebellar stimulation on oral-motor control, duration of phonation, articulation and vocal characteristics in 10 patients with cerebral palsy. The patients were evaluated prior to surgery and again after approximately two and six months of cerebellar stimulation. One patient had normal speech, which was not affected by the stimulation; another case with moderate dysarthria due to severe hearing loss was not helped by the stimulation. Seven patients increased their duration of vowel phonation by about two seconds, a significant amount. Four of the patients with moderate dysarthria improved their articulation, particularly for the consonants S, Sh and Th, after two months of stimulation. Two patients had changes in oral-motor control, which included better tongue and lip movements, and two other cases had small alterations in hypernasality or breathiness. Most of the changes in sound production and speech intelligibility appear to be related to improved intra-oral breath control.