Subjective Assessments of Voice in Parkinson's Disease Subjects with and Without STN-DBS Therapy

Introduction: The causal relation between STN-DBS and speech problems and the associated clinical features are in the incipient stages of being investigated.

Methods: All the Parkinson's disease (PD) subjects with and without STN-DBS who applied to our movement disorders outpatient clinics between January 2022 and June 2022 and agreed to participate in the study were enrolled. The demographic data and clinical features were noted. Besides, the MDS-UPDRS was administered during the medication off-state in all subjects. All the participants completed the voice handicap index (VHI). Besides, the Freezing of Gait Questionnaire (FOGQ) and the quality of life (QoL) scales including the Parkinson's Disease Questionnaire (PDQ-39) and the Schwab and England Activities of Daily Living (ADL) scale were also administered to all the individuals.

Results: We have included 66 patients with PD (F/M = 23/43). Thirty-five patients were those with DBS therapy whereas 31 patients were without. The results of the comparative analyses between the patients with and without DBS therapy revealed that the DBS group had a higher disease duration ( = 0.006) and FOGQ scores ( = 0.008). The VHI scores did not differ between groups ( = 0.577), and the correlation analyses did not reveal an association between the VHI scores and the duration of DBS therapy. However, the VHI scores correlated with the disease duration as well as the FOG scores.

Conclusion: We did not find convincing evidence supporting the increased risk of speech disturbance with STN-DBS therapy. We suggest that the frequent existence of speech disturbance in this patient subgroup with STN-DBS is associated with the classical nature of PD.