Effectiveness Of Speech Therapy Interventions In Parkinsonism: Mechanisms And Rehabilitation: A Systematic Review

Abstract

Background: Speech impairments, especially hypokinetic dysarthria, affect up to 89% of Parkinson’s disease patients, impairing communication, and general lifestyle. Speech-language therapy (SLT) is a key non-drug approach, offering greater benefit than medications for speech issues.

Objective: This systematic review evaluates the efficiency of speech and language therapy in Parkinsonism, investigates underlying therapeutic mechanisms, and examines the impact of delivery modes and personalized intervention strategies.

Methods: A complete literature search was conducted following the PRISMA 2020 guidelines. Studies included adults with Parkinson’s disease receiving speech and language therapy (SLT) interventions, such as Lee Silverman Voice Treatment (LSVT) LOUD, LSVT ARTICulation, clear speech strategies, music therapy, and telehealth-based programs. 13 studies met inclusion criteria: randomized controlled trials, experimental, and quasi-experimental designs.

Results: LSVT LOUD significantly improved vocal loudness, speech intelligibility, and quality of life. Telehealth-based SLT showed comparable efficacy to in-person delivery, improving accessibility. Multi-modal and customized approaches yielded positive outcomes in communication and functional independence. However, heterogeneity in protocols and outcome measures limited cross-study comparability.

Conclusion: SLT interventions, particularly LSVT LOUD, are effective in improving speech outcomes in PD. Emerging modalities such as telehealth and individualized, multi-disciplinary rehabilitation enhance therapy accessibility and impact. Future research should prioritize long-term, patient-centered studies and standardized outcome metrics to strengthen evidence-based clinical practice.