Effects of tDCS on Apraxia of Speech in Non-Fluent Primary Progressive Aphasia

Summary

Primary progressive aphasia (PPA) is a neurodegenerative disease that affects first and foremost language abilities. There are three different variants of PPA, each a relatively distinct speech and language profile. For individuals with non-fluent variant PPA (nfvPPA), a core symptom is apraxia of speech (AOS), which is defined as an oral motor speech disorder. Such a disorder inhibits one's ability to translate speech plans into motor plans and results in longer segmental durations and reduced rate of syllabic production.

This research project investigates the behavioral and neuromodulatory effects of transcranial direct current stimulation (tDCS) during language therapy in participants with nfvPPA over time. Anodal tDCS targeting the left inferior frontal gyrus (IFG) administered in combination with language therapy is expected to be more beneficial when compared to language therapy alone (sham). The investigators believe tDCS during language therapy will 1) improve language performance or decrease rate of decline, 2) promote better-sustained effects at 2 weeks and 2 months post-treatment, and 3) produce generalization to untrained language items and some other cognitive functions. Resting-state fMRI, diffusion tensor imaging (DTI), and volumetric data are also collected to investigate changes in functional brain connectivity associated with tDCS in individuals with PPA.

A better understanding of the therapeutic and neuromodulatory mechanisms of tDCS as an adjunct to language therapy in nfvPPA may have a significant impact on the development of effective therapies for PPA, and may offer insight into ways of impeding neurodegeneration that may improve patients' quality of life, as well as extend patients' ability to work and manage patients' affairs.

Conditions

• Primary Progressive Aphasia

Interventions

DEVICE

Active tDCS plus Speech-Language Therapy

Stimulation will be delivered by a battery-driven constant current stimulator. The electrical current will be administered to a pre-specified region of the brain (inferior frontal gyrus). The stimulation will be delivered at an intensity of 2 mA (estimated current density 0.04 mA/cm\^2; estimated total charge 0.048 C/cm\^2) in a ramp-like fashion for a maximum of 20 minutes. Speech-language therapy will target apraxia of speech (AOS).

DEVICE

Sham plus Speech-Language Therapy

Speech-language therapy will be administered during sham stimulation. Current will be administered in a ramp-line fashion but after the ramping the intensity will drop to 0 mA. Speech-language therapy will target apraxia of speech (AOS).

Sponsors & Collaborators

• Johns Hopkins University

  lead OTHER

Principal Investigators

• Kyrana Tsapkini, PhD · Johns Hopkins University

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

50 Years

Max Age

90 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2013-04-30

Primary Completion

2025-04-30

Completion

2025-04-30

FDA Device

Yes

Countries

• United States

Study Locations