An investigation of the effects of subthalamic nucleus stimulation on acoustic measures of voice
Dromey, C., Kumar, R., Lang, A., & Lozano, A. (2000) An investigation of the effects of subthalamic nucleus stimulation on acoustic measures of voice , 15 (6), 1132-1138
This study examined the effects of DBS-STN on acoustic measures of voice. Seven patients were assessed before and six-months after bilateral DBS-STN. Patient’s speech was assessed both on and off medication during the pre and post-surgery evaluations. Two primary speech variables were assessed: fundamental frequency and speech intensity. Fundamental frequency corresponds to the listener’s perception of pitch. Speech intensity corresponds to the perception of how weak or strong a person’s voice is. The results found only modest improvements in speech functioning and, according to the authors, "the overall impact is not substantial and would not represent a functionally useful change in speech performance." The authors note that the patient’s speech was only mildly impaired before surgery and therefore improvement may have been difficult to detect.