Fluency-Enhancing Strategies for Hypokinetic Dysarthria Exacerbated by Subthalamic Nucleus Brain Stimulation: A Case Study

Abstract

Introduction Speech disorders associated with Parkinson's disease (PD) and the pharmaceutical treatments of PD are well documented. A relatively recent treatment alternative for PD is deep brain stimulation (DBS) of the subthalamic nucleus (STN), which is used to manage the symptoms of PD as the disease progresses. This case study documented the speech characteristics of a unique client with PD STN-DBS and reported initial findings on a variety of fluency- and intelligibility-enhancing strategies. Method A speech-language pathologist referred a 63-year-old man, previously diagnosed by a speech-language pathologist with neurogenic stuttering as a result of an STN-DBS battery change, for a speech evaluation, reporting lack of success with traditional stuttering treatment strategies. The client's speech was assessed, and a variety of fluency- and intelligibility-enhancing techniques were tested during trial therapy. Results The client's speech exhibited the hallmark characteristics of hypokinetic dysarthria, including speech disfluencies. A variety of pacing and prosthetic strategies were tested, revealing that auditory and tactile prosthetic speech feedback provided optimal improvements in fluency and intelligibility. Discussion These results suggest that the prosthetic speech feedback provided optimal intelligibility and fluency enhancement and could potentially improve articulation and speech volume, which are also common in cases of hypokinetic dysarthria.