Brain and Language 78, 233–240 (2001) doi:10.1006/brln.2001.2466, available online at http://www.idealibrary.com on Effect of Bilateral Stimulation of the Subthalamic Nucleus on Parkinsonian Voice M. Gentil, P. Chauvin, S. Pinto, P. Pollak, and A. L. Benabid INSERM, Unite ´ 318, Centre Hospitalier Universitaire de Grenoble, Grenoble, France Published online June 21, 2001 The purpose of this study was to assess several acoustic features of the voices of 26 parkinso- nian patients under two conditions, with and without bilateral chronic stimulation of the subtha- lamic nucleus (STN) to estimate the effectiveness of this procedure on parkinsonian speech. When compared to unstimulated patients, stimulated patients showed longer duration of sus- tained vowels, shorter duration of sentences, nonsense words, and pauses, more variable funda- mental frequency ( f 0) in sentences, and more stable f 0 during sustained vowels. Relative intensity was unchanged in both conditions. Further acoustic analyses are warranted to clarify the role of STN stimulation on parkinsonian speech.  2001 Academic Press Key Words: Parkinson’s disease; surgical treatment; subthalamic nucleus stimulation; dysar- thria; voice; acoustic analysis. Voice abnormalities of patients with Parkinson’s disease (PD) include breathy or rough voice quality (Darley, Aronson, & Brown, 1969; Hanson, Geratt, & Ward, 1984; Logemann et al., 1978), monotonous voice reduced in pitch and loudness vari- ability (Aronson, 1990; Brin et al., 1992; Cummings et al., 1988), reduced loudness (Adams & Lang, 1992; Ramig, 1995), and short rushes of speech and long-duration silent hesitations (Illes, 1989; Netsell, Daniel, & Celesia, 1975). Given the frequency of occurrence of voice disorders among patients with PD, phonatory capabilities should be quantified for research objectives, mostly to provide baseline data from which to consider treatment-related changes. Levodopa therapy is an efficient treatment for PD, but long-term dopaminergic therapy is often complicated by motor fluctuations difficult to control. Advances in understanding the basal ganglia and its role in the pathogenesis of PD (Alexander et al., 1990; DeLong, 1990) coupled with refinements in imaging and surgical tech- niques have renewed interest in the surgical treatment of PD. In particular, since 1993, stimulation of the STN has been used to treat patients with disabling PD and severe motor fluctuations. Stimulation of the STN is effective for the main signs of parkinsonism—bradykinesia, rigidity and tremor—and greatly improves parkinso- nian motor disability (Limousin et al., 1995, 1998; Krack et al., 1997). Although the effectiveness of this procedure on the articulatory organs is known (Gentil et al., 1999) the precise effect of STN stimulation on parkinsonian voice is not. It is impor- tant to evaluate this effect because we know that electrical stimulations of other tar- gets, such as the ventral intermediate nucleus of the thalamus (VIM), have detrimental Address correspondence and reprint requests to Miche `le Gentil, Centre Hospitalier Universitaire de Grenoble, Service Neurologie, BP 217, 38043 Grenoble cedex 9, France. E-mail: michele.gentil @ujf-grenoble.fr. 233 0093-934X/01 $35.00 Copyright  2001 by Academic Press All rights of reproduction in any form reserved.