Effects of transcutaneous electrical nerve stimulation and manual laryngeal therapy on muscle tension dysphonia: randomized clinical trial.
Isadora de Oliveira Lemos, Kelly Cristina Alves Silvério, Mauriceia Cassol
Combining TENS with laryngeal manual therapy was the only approach that reduced vocal tension in women with muscle tension dysphonia.
LMT alone improved overall voice quality; TENS alone did not. All three groups reported less vocal fatigue and musculoskeletal pain.
Key findings
1On the primary outcome of overall vocal deviation (GRBAS G score), LMT and TENS+LMT both showed a statistically significant improvement, while TENS alone did not reach significance. Only the TENS+LMT group showed a significant reduction in vocal tension (GRBAS S score).
2All three groups showed significant reductions in vocal symptom scores (VSS), vocal fatigue scores (VFI), and increases in maximum phonation times, with no statistically significant differences between the groups on these secondary measures.
3Muscle tension upon palpation decreased significantly in all three groups, with the TENS+LMT group showing the largest reduction in the total score and a statistically significant difference from the other two groups.
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What it does not show
There was no control group, so it is impossible to separate the effect of the specific techniques from the effect of six weeks of regular therapist contact, repeated assessments, or the passage of time. Only 28 of the 44 women who were randomised completed the study, a 36% dropout rate that the paper does not break down by group. The groups were imbalanced: the LMT group had no voice professionals and 80% had no laryngeal diagnosis, while the TENS and TENS+LMT groups were predominantly voice professionals with laryngeal findings. The authors adjusted statistically, but with 9 to 10 people per group, chance differences are hard to control. No acoustic voice analysis or laryngeal imaging was performed after treatment, so the vocal quality findings rest entirely on three raters' perceptual scores. The laryngeal palpation scale used to measure muscle tension had not been validated in Brazilian Portuguese at the time of the study; the authors translated and adapted it themselves. All participants were women, so the findings cannot be extended to men.
Declared interests
No funding source was declared and no conflicts of interest were reported.
The easy way to misread this
Do not read the improvement seen in all three groups as proof that TENS, LMT, or their combination specifically causes the change. There was no control group, so the gains could reflect six weeks of regular therapist contact, the repeated assessment process, or the natural course of the condition rather than the technique itself. The between-group differences are the only part that points to one approach being better than another, and even those rest on 9 to 10 people per arm.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →