Unilateral deep brain stimulation of the pedunculopontine tegmental nucleus improves oromotor movements in Parkinson’s disease

Abstract Background Jaw movements are severely affected in Parkinson’s disease. Deep brain stimulation (DBS) of basal ganglia targets is known to ameliorate oromotor control. In this study, we examined the effects of DBS of the pedunculopontine tegmental nucleus (PPTg) on jaw movements in selected parkinsonian patients. Methods The effects of low-frequency (25 Hz) stimulation of the PPTg on jaw movements were investigated through electrognathographic analysis in parkinsonian patients who were selected for PPTg stimulation. Changes in jaw velocity and amplitude during voluntary opening and closing movements of the mouth, as well as the maximum frequency of self-paced sequences of opening and closing cycles, were analyzed. Results Low-frequency stimulation of the PPTg in the OFF-drugs condition significantly improved the opening and closing velocities, vertical amplitude and rhythm of voluntary movements. In some instances, movement parameters during stimulation were within the range of those recorded in healthy controls. Discussion This is the first study investigating the impact of PPTg DBS on oromotor control in parkinsonian patients. The results show that jaw movements may be restored under stimulation and suggest that the pedunculopontine nucleus may play a key role in controlling oromotor activity.