Intensive Speech Therapy for Hypokinetic Dysarthria in Parkinson's Disease: Targeting the Five Subsystems of Speech Production with Clinical and Instrumental Evaluation.

Background: Hypokinetic dysarthria is a speech disorder observed in almost 90% of PD patients that can appear at any stage of the disease, usually worsening as the disease progresses. Today, speech therapy intervention in PD is seen as a possible therapeutic option to alleviate and slow down the progression of symptoms. This study aims to investigate the validity of traditional speech therapy in dysarthria with the aim of improving the quality of life of PD patients, by comparing subjective clinical assessment with objective instrumental measures (IOPI and voice analysis). Methods: This is an observational study of 30 patients with hypokinetic dysarthria due to PD. The patients underwent speech therapy treatment with a frequency of three times per week for 12 consecutive weeks. Patients were evaluated at the time of enrollment (T0), at the start of treatment (T1), and at the end of the same (T2). Six months after the end of treatment (T3), a follow-up was performed based on disability and phonatory evaluation. Results: This study showed significant improvements (<0.001) from the start (T1) to the end of treatment (T2), with increases in the Barthel Index score, Robertson Dysarthria Profile, and IOPI measurements for tongue and lip strength, along with enhanced phonometer scores and tongue endurance. Correlations highlighted that tongue endurance decreased with age, CIRS, and MDS-UPDRS, while showing a positive association with MoCA scores. Conclusions: Significant improvements were observed in tongue and lip strength, phonatory duration, intensity, and vocal quality between pre- (T1) and post-treatment (T2). This study underscores the importance of early and continuous speech therapy treatment for comprehensive speech function enhancement.