Roozbeh Behroozmand1, Karim Johari2, Ryan M Kelley3, Efthymia C Kapnoula4, Nandakumar S Narayanan5, Jeremy D W Greenlee6. 1. Speech Neuroscience Lab, Department of Communication Sciences and Disorders, University of South Carolina, Columbia, SC 29028, USA. Electronic address: r-behroozmand@sc.edu. 2. Speech Neuroscience Lab, Department of Communication Sciences and Disorders, University of South Carolina, Columbia, SC 29028, USA. 3. Medical Scientist Training Program, University of Iowa, Iowa City, IA 52242, USA; Program in Neuroscience, University of Iowa, Iowa City, IA 52242, USA. 4. Basque Center on Cognition, Brain and Language, San Sebastian, Spain. 5. Department of Neurology, University of Iowa, Iowa City, IA 52242, USA. 6. Human Brain Research Lab, Department of Neurosurgery, University of Iowa, Iowa City, IA 52242, USA.
Abstract
INTRODUCTION: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for limb motor symptoms in Parkinson's disease (PD); however, its effect on vocal motor function has yielded conflicted and highly variable results. The present study investigated the effects of STN-DBS on the mechanisms of vocal production and motor control. METHODS: A total of 10 PD subjects with bilateral STN-DBS implantation were tested with DBS ON and OFF while they performed steady vowel vocalizations and received randomized upward or downward pitch-shift stimuli (±100 cents) in their voice auditory feedback. RESULTS: Data showed that the magnitude of vocal compensation responses to pitch-shift stimuli was significantly attenuated during DBS ON vs. OFF (p = 0.012). This effect was direction-specific and was only observed when subjects raised their voice fundamental frequency (F0) in the opposite direction to downward stimuli (p = 0.019). In addition, we found that voice F0 perturbation (i.e. jitter) was significantly reduced during DBS ON vs. OFF (p = 0.022), and this DBS-induced modulation was positively correlated with the attenuation of vocal compensation responses to downward pitch-shift stimuli (r = +0.57, p = 0.028). CONCLUSIONS: These findings provide the first data supporting the role of STN in vocal F0 motor control in response to altered auditory feedback. The DBS-induced attenuation of vocal compensation responses may result from increased inhibitory effects of the subcortical hyperdirect (fronto-subthalamic) pathways on the vocal motor cortex, which can help stabilize voice F0 and ameliorate vocal motor symptoms by impeding PD subjects' abnormal (i.e. overshooting) vocal responses to alterations in the auditory feedback.
INTRODUCTION: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for limb motor symptoms in Parkinson's disease (PD); however, its effect on vocal motor function has yielded conflicted and highly variable results. The present study investigated the effects of STN-DBS on the mechanisms of vocal production and motor control. METHODS: A total of 10 PD subjects with bilateral STN-DBS implantation were tested with DBS ON and OFF while they performed steady vowel vocalizations and received randomized upward or downward pitch-shift stimuli (±100 cents) in their voice auditory feedback. RESULTS: Data showed that the magnitude of vocal compensation responses to pitch-shift stimuli was significantly attenuated during DBS ON vs. OFF (p = 0.012). This effect was direction-specific and was only observed when subjects raised their voice fundamental frequency (F0) in the opposite direction to downward stimuli (p = 0.019). In addition, we found that voice F0 perturbation (i.e. jitter) was significantly reduced during DBS ON vs. OFF (p = 0.022), and this DBS-induced modulation was positively correlated with the attenuation of vocal compensation responses to downward pitch-shift stimuli (r = +0.57, p = 0.028). CONCLUSIONS: These findings provide the first data supporting the role of STN in vocal F0 motor control in response to altered auditory feedback. The DBS-induced attenuation of vocal compensation responses may result from increased inhibitory effects of the subcortical hyperdirect (fronto-subthalamic) pathways on the vocal motor cortex, which can help stabilize voice F0 and ameliorate vocal motor symptoms by impeding PD subjects' abnormal (i.e. overshooting) vocal responses to alterations in the auditory feedback.
Authors: Adam R Aron; Sarah Durston; Dawn M Eagle; Gordon D Logan; Cathy M Stinear; Veit Stuphorn Journal: J Neurosci Date: 2007-10-31 Impact factor: 6.167
Authors: F Klostermann; F Ehlen; J Vesper; K Nubel; M Gross; F Marzinzik; G Curio; T Sappok Journal: J Neurol Neurosurg Psychiatry Date: 2007-08-31 Impact factor: 10.154