The Effect of Green & Red Light Therapy on Hearing

Low-level laser therapy

Low-level laser therapy (LLLT) has been practiced for over 20 years in Europe and has been introduced in the United States as a treatment for pain and postsurgical tissue repair. It has been proposed that laser energy in the red and near-infrared light spectrum may aid in the repair of tissue damage. A proposed mechanism for this therapeutic effect is the stimulation of mitochondria in the cells to produce more energy through the production of adenosine triphosphate.

Studies in humans have investigated the effects of LLLT on both hearing loss and tinnitus, with equivocal results. Some studies have found an improvement in hearing thresholds and tinnitus symptoms.

The Subjects

A total of 35 adult subjects were enrolled in the study. Two subjects withdrew from the study due to loss of interest and/or scheduling difficulty. The data from three additional subjects were not included in the analysis. One subject yielded unreliable audiometric and speech understanding data, speech scores could not be obtained from one subject with a profound hearing loss, and calibration problems compromised data from the third subject. Data from the remaining 30 subjects were included in the analyses. The experimental protocol was approved by the Institutional Review Board of The University of Iowa, and written informed consent was obtained from all participants.

The Device

An Erchonia EHL laser was used to provide the laser stimulation. The device was a portable unit that consisted of a hand-held probe and a main body. The probe contained two laser diodes. One diode produced light in the green part of the visible light spectrum (532 nm wavelength), and the other diode produced light in the red part of the visible light spectrum (635 nm wavelength). Both diodes produced energy levels of 7.5 mW (class IIIb). The laser beams from both diodes were dispersed through lenses to create parallel line-generated beams, rather than spots. A second Erchonia EHL device served as the placebo. It was identical to the treatment device, except that the laser diodes were replaced with nonfunctioning standard light-emitting diodes.

The Groups

The study used three groups: treatment, placebo, and control. Subjects were pseudorandomly assigned to one of the three groups.

Initial group assignment was random with occasional adjustment to ensure that the three groups were similar in terms of number of participants, female/male ratio, mean age of participants, and mean pure-tone audiometric thresholds. The treatment group received the laser treatment protocol using the functional laser device. The placebo group also received the laser treatment protocol, but using the nonfunctioning laser device. The control group made similarly timed visits to the laboratory but received no real or feigned “treatment.” The study used a repeated-measures design, with each subject taking a battery of pretests, followed by treatment followed by a battery of posttests.

Analysis

Data were obtained from both ears of each subject. Since no obvious differences were seen between left and right ears, data from both ears were combined in the following analyses. Strictly speaking, this likely violates the statistical assumption of independent sampling, since the test results from left and right ears of a single subject are likely to be highly correlated. None of the statistical tests used in the analyses are robust to the assumption of independent sampling, and the effect of including both ears is likely to be that of artificially increasing the sample size, making it more likely that a statistically significant result will be found. All statistical tests were conducted using a significance level of .

Conclusions

No statistically significant effect of LLLT on auditory function was found, as assessed by pure-tone audiometry, speech understanding, and TEOAEs in this test. Additionally, no individual subjects showed any clinically significant change. It remains possible that other methods of LLLT could have an effect on hearing. The type of device used was not the best one for this type of study. Further research elucidating the anatomic and physiologic bases for therapeutic effects of LLLT on hearing are needed before further clinical testing is warranted.

More References

Clinical Study | Open Access. Volume 2013 |Article ID 916370 | https://doi.org/10.1155/2013/916370

ClinicalTrials.gov (NCT01820416)

T. I. Karu, “Molecular mechanism of the therapeutic effect of low-intensity laser radiation,” Lasers in the Life Sciences, vol. 2, no. 1, pp. 53–74, 1988.View at: Google Scholar

L. Wilden and R. Karthein, “Import of radiation phenomena of electrons and therapeutic low-level laser in regard to the mitochondrial energy transfer,” Journal of Clinical Laser Medicine and Surgery, vol. 16, no. 3, pp. 159–165, 1998.View at: Google Scholar

J. Kujawa, L. Zavodnik, I. Zavodnik, V. Buko, A. Lapshyna, and M. Bryszewska, “Effect of low-intensity (3.75–25 J/cm2) near-infrared (810 nm) laser radiation on red blood cell ATPase activities and membrane structure,” Journal of Clinical Laser Medicine and Surgery, vol. 22, no. 2, pp. 111–117, 2004.View at: Google Scholar

C. K. Rhee, C. W. Bahk, P. S. Chung, J. Y. Jung, M. W. Suh, and S. H. Kim, “Effect of low-level laser treatment on cochlea hair-cell recovery after acute acoustic trauma,” Journal of Biomedical Optics, vol. 17, no. 6, Article ID 068002, 2012.View at: Google Scholar

G. I. Wenzel, B. Pikkula, C. H. Choi, B. Anvari, and J. S. Oghalai, “Laser irradiation of the guinea pig basilar membrane,” Lasers in Surgery and Medicine, vol. 35, no. 3, pp. 174–180, 2004.View at: Publisher Site | Google Scholar

P. Plath and J. Olivier, “Results of combined low-power laser therapy and extracts of Ginkgo biloba in cases of sensorineural hearing loss and tinnitus,” Advances in Oto-Rhino-Laryngology, vol. 49, pp. 101–104, 1995.View at: Google Scholar

S. Tauber, W. Beyer, K. Schorn, and R. Baumgartner, “Transmeatal cochlear laser (TCL) treatment of cochlear dysfunction: a feasibility study for chronic tinnitus,” Lasers in Medical Science, vol. 18, no. 3, pp. 154–161, 2003.View at: Publisher Site | Google Scholar

A. Gungor, S. Dogru, H. Cincik, E. Erkul, and E. Poyrazoglu, “Effectiveness of transmeatal low power laser irradiation for chronic tinnitus,” Journal of Laryngology and Otology, vol. 122, no. 5, pp. 447–451, 2008.View at: Publisher Site | Google Scholar

D. Cuda and A. de Caria, “Effectiveness of combined counseling and low-level laser stimulation in the treatment of disturbing chronic tinnitus,” International Tinnitus Journal, vol. 14, no. 2, pp. 175–180, 2008.View at: Google Scholar

A. H. Salahaldin, K. Abdulhadi, N. Najjar, and A. Bener, “Low-level laser therapy in patients with complaints of tinnitus: a clinical study,” ISRN Otolaryngology, vol. 2012, Article ID 132060, 5 pages, 2012.View at: Publisher Site | Google Scholar

M. Rogowski, S. Mnich, E. Gindzieńska, and B. Lazarczyk, “Low-power laser in the treatment of tinnitus — a placebo-controlled study,” Otolaryngologia Polska, vol. 53, no. 3, pp. 315–320, 1999.View at: Google Scholar

F. Mirz, R. Zachariae, S. E. Andersen et al., “The low-power laser in the treatment of tinnitus,” Clinical Otolaryngology and Allied Sciences, vol. 24, no. 4, pp. 346–354, 1999.View at: Publisher Site | Google Scholar

T. Nakashima, H. Ueda, H. Misawa et al., “Transmeatal low-power laser irradiation for tinnitus,” Otology and Neurotology, vol. 23, no. 3, pp. 296–300, 2002.View at: Google Scholar

R. Teggi, C. Bellini, B. Fabiano, and M. Bussi, “Efficacy of low-level laser therapy in Ménière’s disease: a pilot study of 10 patients,” Photomedicine and Laser Surgery, vol. 26, no. 4, pp. 349–353, 2008.View at: Publisher Site | Google Scholar

R. Teggi, C. Bellini, L. O. Piccioni, F. Palonta, and M. Bussi, “Transmeatal low-level laser therapy for chronic tinnitus with cochlear dysfunction,” Audiology and Neurotology, vol. 14, no. 2, pp. 115–120, 2009.View at: Publisher Site | Google Scholar

C. H. Graham, “Behavior, perception and the psychophysical methods,” Psychological Review, vol. 57, no. 2, pp. 108–120, 1950.View at: Publisher Site | Google Scholar

M. Nilsson, S. D. Soli, and J. A. Sullivan, “Development of the hearing in noise test for the measurement of speech reception thresholds in quiet and in noise,” Journal of the Acoustical Society of America, vol. 95, no. 2, pp. 1085–1099, 1994.View at: Google Scholar

R. M. Cox, G. C. Alexander, and C. Gilmore, “Development of the connected speech test (CST),” Ear and Hearing, vol. 8, no. 5, supplement, pp. 119S–126S, 1987.View at: Google Scholar

R. M. Cox, G. C. Alexander, C. Gilmore, and K. M. Pusakulich, “Use of the connected speech test (CST) with hearing-impaired listeners,” Ear and Hearing, vol. 9, no. 4, pp. 198–207, 1988.View at: Google Scholar

R. Probst, B. L. Lonsbury-Martin, and G. K. Martin, “A review of otoacoustic emissions,” Journal of the Acoustical Society of America, vol. 89, no. 5, pp. 2027–2067, 1991.View at: Google Scholar

D. H. Keefe, “Double-evoked otoacoustic emissions — I: measurement theory and nonlinear coherence,” Journal of the Acoustical Society of America, vol. 103, no. 6, pp. 3489–3498, 1998.View at: Publisher Site | Google Scholar

G. A. Studebaker, “A “rationalized” arcsine transform,” Journal of Speech and Hearing Research, vol. 28, no. 3, pp. 455–462, 1985.View at: Google Scholar

R. S. Schlauch and P. Nelson, “Puretone evaluation,” in Handbook of Clinical Audiology, J. Katz, L. Medwestsky, R. Burkard, and L. Hood, Eds., pp. 30–49, Lippincott Williams & Wilkins, Baltimore, Md, USA, 2009.View at: Google Scholar

L. E. Humes, D. L. Wilson, N. N. Barlow, and C. Garner, “Changes in hearing-aid benefit following 1 or 2 years of hearing-aid use by older adults,” Journal of Speech, Language, and Hearing Research, vol. 45, no. 4, pp. 772–782, 2002.View at: Google Scholar

M. S. Robinette, M. J. Cevette, and R. Probst, “Otoacoustic emissions and audiometric outcomes across cochlear and retrocochlear pathology,” in Otoacoustic Emissions: Clinical Applications, S. Robinette and T. J. Glattke, Eds., pp. 227–272, Thieme, New York, NY, USA, 2007.View at: Google Scholar


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