Effects of Transcutaneous Electrical Nervous Stimulation (TENS) on Dysphonic Patients: A Systematic Review Study

Background and Objectives: Transcutaneous electrical nerve stimulation (TENS), a pain-alleviating and muscle-relaxing treatment used in physio-therapeutic clinical practice, has recently appeared to be just as effective in dysphonia. This review aimed at clarifying whether TENS can be an effective practice in dysphonia therapy and/or management on its own or combined with other types of interventions and, hence, whether its practice can be a useful, more widespread establishment to speech and language therapy intervention methods. Materials and Methods: A search was conducted on the PubMed database using specific terms based on the PICO search strategy. Eventually, four randomized controlled studies and four clinical trials were included. The methodological quality of the included studies was evaluated using the physiotherapy evidence-based database (PEDro) assessment tool, and this indicated high-quality research with an average score of 8.43. Results: The studies utilized various TENS devices, predominantly the Dualpex 961 device (frequency of 10 Hz, phase of 200 ms). The assessment methods varied, including auditory perception, vocal therapy, electrostimulation, audio and video perceptual assessments, and laryngeal evaluations. The clinical outcomes of TENS showed a reduction in musculoskeletal pain in various areas, while the acoustic analysis results were significant in only one study. TENS was compared to manual laryngeal therapy (LMT), placebo TENS, and vocal therapy in different studies with mixed results. Conclusions: This review supports the idea that a multidimensional approach, incorporating various therapeutic modalities (TENS, LMT, speech therapy, and vocal training) can yield positive outcomes for patients with voice disorders. Further research is needed to explore the specific mechanisms of action and optimal treatment protocols for TENS in voice therapy.