Transcutaneous Electrical Nerve Stimulation in Dysphonic Patients: A Systematic Review.

OBJECTIVE: This paper aims to systematically review the application methods and clinical outcomes of transcutaneous electrical nerve stimulation (TENS) in the rehabilitation of dysphonic patients. METHODS: The study consists of a systematic review performed in the Medline (via PubMed), Cochrane Library, Scopus and Lilacs databases, using a search strategy related to the research theme. Inclusion criteria involve experimental studies that investigated the effects of TENS on dysphonic patients, published in the last 15 years in Portuguese, English or Spanish. The Physiotherapy Evidence-Based Database was used to evaluate the methodological quality of the articles. RESULTS: In the first search, 100 publications were found, 57 of which were duplicated and 23 did not address TENS as an intervention. According to the exclusion criteria of the remaining 20 studies, eight were selected for this review. The studies showed a pattern regarding the application of TENS. Of the studies analyzed, 87.5% had effective results after the intervention. Regarding pain, studies have found a reduction of this symptom in the neck, shoulders, back, masseter, and larynx. In the perceptual analysis, an improvement was verified in the parameters of tension, breathiness, roughness, instability, and asthenia. In addition, different types of vocal symptoms such as pain, burning, lump in the throat and effort to speak were reduced after TENS. CONCLUSION: Although the studies included in this review indicate that there were changes related to the reduction of vocal symptoms, reduction of pain and improvement of vocal quality after the application of TENS in dysphonic patients, studies with a higher level of evidence and rigorous assessments of methodological quality are necessary so that findings are more robust and replicable in clinical practice.