Efficacy of LSVT-LOUD Therapy on Voice, Speech, and Quality of Life in Parkinson's Disease

This study implements the standardized Lee Silverman Voice Treatment (LSVT-LOUD) protocol, an intensive intervention focused on the recalibration of vocal effort through motor learning principles. The intervention requires participants to attend individual therapy sessions conducted four times per week over a four-week period, with each session lasting 60 minutes.

The protocol emphasizes high-effort phonation and is structured into the following components:

Daily Tasks: Sustained vowel phonation (maximum duration and stability), pitch range exercises (high-to-low and low-to-high glides), and maximum functional loudness drills using high-effort speech.

Hierarchy Tasks: Systematic progression from word-level to sentence-level and, finally, conversational speech tasks, incorporating high-effort vocal production into increasingly complex linguistic structures.

Carry-over Exercises: Daily practice assignments designed to facilitate the generalization of high-effort speech into activities of daily living and social interactions.

Clinical instruction emphasizes the patient's sensory perception of vocal effort, using acoustic feedback to help participants recalibrate their internal perception of 'loud' versus 'normal' speech. The protocol is conducted in Turkish, adhering to the original LSVT-LOUD methodological requirements while accounting for linguistic nuances of the Turkish language.

Inclusion criteria

Diagnosis: Patients with a confirmed diagnosis of Idiopathic Parkinson's Disease (Hoehn and Yahr stages I-III).

Age: Individuals aged 40-80 years.

Language: Native Turkish speakers.

Cognitive Status: Sufficient cognitive function to participate in therapy (e.g., Mini-Mental State Examination (MMSE) score ≥ 24).

Communication: Presence of voice or speech impairment (e.g., hypophonia, reduced intelligibility) as confirmed by a speech-language pathologist.

Stability: Stable medication regimen for at least 1 month prior to the study initiation.

Exclusion criteria

Neurological Comorbidities: Presence of other significant neurological disorders (e.g., stroke, traumatic brain injury, multiple sclerosis) or active voice disorders (e.g., vocal cord nodules, laryngeal cancer).

Hearing Impairment: Uncorrected hearing loss that would interfere with speech assessment or therapy.

Cognitive Impairment: Diagnosis of dementia or severe cognitive impairment that prevents participation in the intensive LSVT-LOUD protocol.

Recent Surgery: History of laryngeal surgery or deep brain stimulation (DBS) within the last 6 months.

Therapy History: Previous experience with LSVT-LOUD or intensive speech therapy within the past year.