Longitudinal Speech Change After Subthalamic Nucleus Deep Brain Stimulation in Parkinson’s Disease Patients: A 2-Year Prospective Study

Abstract

Background: Speech disorders are among the most common adverse effects after subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson's disease (PD) patients. However, longitudinal speech changes after STN-DBS are not fully understood. Objective: We performed a two-year prospective study on PD patients who underwent STN-DBS and analyzed changes in speech function to clarify factors predicting for speech deterioration. Methods: Twenty-five PD patients were assessed before and up to two years after STN implantation. Speech function was evaluated in the on-stimulation condition and 30 min after stimulation cessation using auditory-perceptual assessment. Patients who experienced overall worsening in speech intelligibility or naturalness ≥1 point during follow-up were classified into a deteriorated group (n = 16), with the remaining subjects being classified into a stable group (n = 9). Cognitive and motor functions were also assessed. Results: The stable group had significantly better values of low volume, monoloudness, and asthenic voice subscores of the auditory-perceptual assessment in the on-stimulation condition compared with the off-stimulation condition. Imprecise consonants, excess loudness variation, and strained voice subscores were improved via cessation of stimulation in both groups. Before surgery, the deteriorated group had significantly lower scores in the Stroop Color-Word Test and Digit Span compared to the stable group.

Results of a Randomized Clinical Trial of Speech After Early Neurostimulation in Parkinson's Disease

“…Anyway, these results contrast strongly with the results of speech performance in patients with advanced PD. At these later stages, speech intelligibility assessments 36,37 and other subjective/perceptual measures 5,38 usually show an undisputable deterioration over such a long observation period.…”

Lee Silverman Voice Treatment for dysarthria in patients with Parkinson’s disease: a systematic review and meta‐analysis

“…Moreover, surgical interventions have also caused an academic debate. For example, deep brain stimulation of the subthalamic nucleus has been proven to be a safe and long-term effective treatment for limb motor symptoms in patients with advanced PD, but the effect on speech remains unclear [45][46][47][48]. Although many studies have demonstrated improvements in some voice characteristics (e.g.…”

Tiefe Hirnstimulation beim idiopathischen Parkinson-Syndrom

“…Nicht durch die THS beeinflussen lässt sich eine orthostatische Dysregulation [9], während sich andere, nicht motorische Symptome wie Blasenentleerungsstörungen [10] oder übermäßiges Schwitzen und Schlafstörungen [11] bessern können. Bezüglich des Sprechens und der Sprache können Patient*innen, deren Dysarthrophonie an die Off-Phasen gebunden ist, mit einer Verringerung dieser Problematik durch die THS rechnen [12], [13].…”

“…Off-gebundene Stimm-und Sprechstörungen können sich unter einer THS stimulationsabhängig auch verbessern [12,13,19]. Die Wortflüssigkeit kann sich postoperativ verschlechtern.…”