Speech and Voice Outcomes Following HD-tDCS Over the Left SMA

Not Applicable

Not yet recruiting

• Conditions: Parkinson Disease

• Registration Number: NCT06245070
• Lead Sponsor: Louisiana State University and A&M College

Brief Summary

Pharmaceutical and neurosurgical treatments reliably ameliorate the cardinal motor symptoms in PD but, they often yield inconsistent outcomes for speech and voice disorders, with some studies showing exacerbation of pre-treatment deficits. Therefore, it is crucial to develop and optimize novel approaches that could simultaneously improve speech and voice deficits in PD and facilitate existing behavioral interventions. This project will investigate the immediate and short-term effects of multiple sessions of HD-tDCS over the left SMA on speech and voice deficits in PD.

Detailed Description

Parkinson's disease (PD) is a movement disorder that affects more than one million individuals in the United States. Over 90 percent of individuals with PD manifest speech and voice impairments in the course of their disease, which can significantly compromise patients' quality of life. While pharmaceutical intervention and deep brain stimulation reliably improve the cardinal motor symptoms of PD, such as tremor, rigidity, and bradykinesia, the effects of these treatments on speech and voice are inconsistent, with some studies showing the exacerbation of pre-treatment deficits. This inconsistency often occurs because treatments are calibrated to ameliorate limb motor symptoms, with no direct optimization to improve speech and voice functions. However, there is no established non-invasive neurostimulation protocol for communication disorders in PD. Increasing evidence supports the application of non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) to improve both motor and non-motor symptoms in PD. However, limited evidence exists regarding the application of tDCS to improve speech and voice disorders in PD. Moreover, there is no established long-term effect of tDCS on speech and voice deficits in PD. In this proposed study, we will address these gaps by investigating the immediate and short-term effects of high definition-transcranial direct current stimulation (HD-tDCS) over the left supplementary motor area (SMA) on speech and voice deficits in 24 PD and 24 matched control participants.

Study Timeline

• Study First Submitted: 2024-01-24
• Status Verified: 2024-02
• Study First Submitted QC: 2024-02-05
• Study First Posted: 2024-02-07
• Last Update Submitted: 2024-02-23
• Last Update Posted: 2024-02-26
• Study Start: 2025-02-02
• Primary Completion: 2028-01-02
• Study Completion: 2028-06-02

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 48

Inclusion Criteria

• Clinical diagnosis of Parkinson's disease
• Native English speakers
• Adequate age-relative hearing and vision to perform the outlined tasks
• Able to provide their own written consent

Exclusion Criteria :

• Neurological disorders besides Parkinson's disease
• Previous brain surgery including deep brain stimulation
• Clinical diagnosis of dementia

Exclusion Criteria

Not provided

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Speech rate	Speech rate will be measured at baseline, immediately after the last session of stimulation, one week and one month after the las stimulation session.	The speech rate ( number of syllables per second) will be calculated during a syllable repetition task for each participant.
Voice loudness measures	Acoustic measures related to voice loudness will be measured at baseline, immediately after the last session of stimulation, one week and one month after the las stimulation session.	Acoustics measures of voice loudness including voice intensity (dB), shimmer (Cycle-to-cycle voice intensity perturbation) and smoothed cepstral peak prominence will be calculated for each participant.
Fundamental frequency measures	Fundamental frequency (F0), jitter (Cycle-to-cycle voice F0 perturbation) and harmonic to noise ration will be calculated for each participant.	Changes in the accuracy rate (percentage of correct repetitions) of non-word repetition
Accuracy of syllable repetition	Accuracy rate for syllable repetition will be measured at baseline, immediately after the last session of stimulation, one week and one month after the las stimulation session.	The number of syllables that correctly produced during syllable repetition task will be calculated for each participant.
Speech rate stability	Speech rate stability will be measured at baseline, immediately after the last session of stimulation, one week and one month after the las stimulation session.	Variability in speech rate across trials for each syllable length ( 1, 2, and 3 ) will be calculated for each participant.