Changes in vocal intensity in Parkinson's disease following pallidotomy surgery

The present study was designed to examine changes in vocal intensity follow ing unilateral posteroventral pallidotomy (PVP) in a large sample of speake rs with Parkinson's disease (PD) that exhibited a range of hypokinetic dysa rthria. Twenty-five persons with PD were recorded using a variety of speech tasks, once prior to and once following PVP. The pre-PVP vocal SPL was sub tracted from the post-PVP vocal SPL to derive a relative change in vocal SP L. Mildly dysarthric participants had significantly greater relative increa ses in vocal SPL following PVP than either moderately or severely dysarthri c participants who had reduced vocal SPL following PVP. If future results f ollow those observed in the present data, mildly dysarthric Parkinson's pat ients may benefit most from unilateral PVP perhaps due to less overall dest ruction of the basal ganglia sensorimotor control circuits involved in oral facial functions, thus increasing the chances to observe improvements post surgery.