Effects of transcutaneous electrical nerve stimulation and manual laryngeal therapy on muscle tension dysphonia: randomized clinical trial

Purpose  To compare the immediate effects of Transcutaneous Electrical Nerve Stimulation (TENS), Laryngeal Manual Therapy (LMT), and the combined application of both in women with Muscle Tension Dysphonia (MTD), considering vocal symptoms, voice quality, aerodynamic measures, and levels of perceived muscle tension on palpation.

Methods  This was a randomized clinical trial including women with a speech-language diagnosis of MTD, allocated into three intervention groups: TENS, LMT, and TENS+LMT. Participants were assessed for vocal symptoms, musculoskeletal pain intensity, perceptual-auditory evaluation of voice quality using the GRBAS scale, maximum phonation times (MPT), S/Z ratio, and levels of perceived muscle tension on palpation using the Laryngeal Palpatory Scale (LPS).

Results  Significant reductions in vocal symptoms, including vocal fatigue, and musculoskeletal pain were observed after the interventions, along with increased MPT in all groups. In the TENS group, breathiness decreased; in the LMT group, there was a significant reduction in overall voice alteration; and in the TENS+LMT group, reductions were observed in overall voice alteration and vocal tension. The LPS also showed a significant decrease in perceived muscle tension during phonation in the TENS+LMT group.

Conclusion  All interventions showed positive effects, with significant reductions in vocal symptoms and musculoskeletal pain, as well as increases in MPT. The combined techniques were able to provide better vocal adjustments and reduce perceived muscle tension on palpation, demonstrating that both approaches were effective in promoting vocal and musculoskeletal benefits.

Keywords:
Voice; Dysphonia; Muscle Tension; Speech Therapy; Transcutaneous Electric Nerve Stimulation; Manual Therapy