The Effectiveness of Low-Level Light Therapy in Attenuating Vocal Fatigue.
Study Goal
The researchers aimed to investigate the effectiveness of low-level light therapy (LLLT) in reducing symptoms of vocal fatigue induced by a vocal loading task, using acoustic, aerodynamic, and self-reported measures.
Results Summary
Vocal loading increased phonation threshold pressure (PTP) and self-perceived vocal effort (IPSV) while decreasing relative fundamental frequency (RFF). Red light LLLT (628 nm) significantly normalized these measures compared to other treatments, suggesting a potential therapeutic effect on vocal fatigue.
Population
16 vocally healthy adults divided into four treatment groups.
Effective Dosage
Infrared wavelength (828 nm) and red wavelength (628 nm) LLLT applied to the laryngeal region.
Duration
Treatment was administered immediately after a 1-hour vocal loading task, with follow-up measurements taken 1 hour post-treatment.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Low-level light therapy (LLLT) | decrease | inflammation | - | - | is effective in reducing | #1 |
Low-level light therapy (LLLT) | increase | wound healing | - | - | promoting | #2 |
Low-level light therapy (LLLT) | decrease | tissue damage | - | - | preventing | #3 |
Vocal loading | increase | Phonation threshold pressure (PTP) | vocally healthy adults | - | significantly increased | #4 |
Vocal loading | increase | inability to produce soft voice (IPSV) self-perceptual rating scale | vocally healthy adults | - | significantly increased | #5 |
Vocal loading | decrease | onset relative fundamental frequency (RFF) | vocally healthy adults | - | decreased | #6 |
Vocal loading | decrease | offset relative fundamental frequency (RFF) | vocally healthy adults | - | decreased | #7 |
Red wavelength LLLT (628 nm) | no change | the combination of PTP, IPSV, and RFF measures | vocally healthy adults | - | significantly normalized | #8 |
Red LLLT | no change | objective and subjective measures of vocal fatigue | - | - | may have a normalizing effect on | #9 |
OBJECTIVES: Low-level light therapy (LLLT) is effective in reducing inflammation, promoting wound healing, and preventing tissue damage, but has not yet been studied in the treatment of voice disorders. The objective of this study was to investigate the possible effectiveness of LLLT in attenuating symptoms of vocal fatigue created by a vocal loading task as measured by acoustic, aerodynamic, and self-reported vocal effort. METHODS: In a randomized, prospective study, 16 vocally healthy adults divided into four groups underwent a 1-hour vocal loading procedure, followed by infrared wavelength LLLT (828 nm), red wavelength LLLT (628 nm), heat, or no heat-light (control) treatment targeting the laryngeal region of the ventral neck surface. Phonation threshold pressure (PTP), relative fundamental frequency (RFF), and the inability to produce soft voice (IPSV) self-perceptual rating scale were recorded (1) at baseline, (2) immediately after vocal loading, (3) after treatment, and (4) 1 hour after treatment. RESULTS: Vocal loading significantly increased PTP and IPSV and decreased onset and offset RFFs, consistent with a shift toward vocal dysfunction. Red light significantly normalized the combination of PTP, IPSV, and RFF measures compared to other conditions. CONCLUSIONS: RFF is sensitive to a vocal loading task in conjunction with PTP and IPSV, and red LLLT may have a normalizing effect on objective and subjective measures of vocal fatigue. The results of this study lay the groundwork and rationale for future research to optimize LLLT wavelength combinations and overall dose.