Objectives:
To analyze the safety and immediate effects of the application of low-power laser in women with vocal health and behavioral dysphonia.

Methods:
This is a randomized experimental study of intra-patient comparison.
First, 36 women without vocal/laryngeal alterations were submitted to an exercise protocol associated with low-power LASER in a single session for analysis of immediate effect in different treatment groups. The experimental groups received the therapeutic light immediately before the vocal technique in a punctual way at seven anatomical points in the cervical region (in both hemilaringes) with the objective of achieving anterior comissura topography of vocal folds, thyroaritenoid muscles, lateral cricoarrhythmiod and cricothyroid. After irradiation, the participants performed the sonorized vibration technique for three minutes. The outcome variables considered were perceptual-auditory analysis of vocal quality, acoustic analysis and self-perception of phonatory effort, measured before and immediately after intervention.
In the group with a diagnosis of behavioral dysphonia, 30 women with dysphonia secondary to glottic clefts or benign lesions of vocal folds randomized and randomized in two groups: placebo and experimental. The voices were recorded before and immediately after procedures and analyzed perceptual-auditory and acoustically.

Results:
The infrared LASER at 9 joules per point before exercise caused improvement of acoustic measures of Shimmer and APQ in normophonic women. In addition, no significant sense of worsening of vocal production was observed. In women with dysphonia, the findings showed an increase of FMT and vowel CPPS, reduction of phonatory effort and improvement of vibrational parameters of vocal folds.

Conclusions:
The results suggest that the energy of 9 joules (total of 63 joules) in the larynx may constitute a possible therapeutic window to be recommended in the vocal clinic in women without vocal and laryngeal alterations, with clear skin and normal body mass index. In addition, these dosimetric parameters are promising, with a possible potentializing effect of vocal results in the treatment of dysphonic women.