Effects of Repetitive Transcranial Magnetic Stimulation in the Rehabilitation of Communication and Deglutition Disorders: Systematic Review of Randomized Controlled Trials

Abstract

Objective: To systematically review randomized controlled trials that evaluate the effects of repetitive transcranial magnetic stimulation (rTMS) on rehabilitation aspects related to communication and swallowing functions.

Methods: A search was conducted on PubMed, Clinical Trials, Cochrane Library, and ASHA electronic databases. Studies were judged according to the eligibility criteria and analyzed by 2 independent and blinded researchers.

Results: We analyzed 9 studies: 4 about aphasia, 3 about dysphagia, 1 about dysarthria in Parkinson's disease and 1 about linguistic deficits in Alzheimer's disease. All aphasia studies used low-frequency rTMS to stimulate Broca's homologous area. High-frequency rTMS was applied over the pharyngoesophageal cortex from the left and/or right hemisphere in the dysphagia studies and over the left dorsolateral prefrontal cortex in the Parkinson's and Alzheimer's studies. Two aphasia and all dysphagia studies showed a significant improvement of the disorder, compared to the sham group. The other 2 studies related to aphasia found a benefit restricted to subgroups with a severe case or injury on the anterior portion of the language cortical area, respectively, whereas the Alzheimer's study demonstrated positive effects specific to auditory comprehension. There were no changes for vocal function in the Parkinson's study.

Conclusion: The benefits of the technique and its applicability in neurogenic disorders related to communication and deglutition are still uncertain. Therefore, other randomized controlled trials are needed to clarify the optimal stimulation protocol for each disorder studied and its real effects.