Effect of low level laser (LLL) on cochlear and vestibular inner ear including tinnitus

Abstract

Objectives: 1. To investigate preventive effect of LLL on gentamicin-induced vestibular ototoxicity.2. To evaluate the effectiveness of lower level laser (LLL) in the treatment of tinnitus. Methods: 1.Twenty guinea pigs were divided into control and laser groups. Vestibular ototoxicity was induced by intratympanic injection of gentamicin into left ear. LLL was irradiated into left ear canal of animals in laser group. Vestibular function of the animals was evaluated with vertical and offvertical axis rotation testing. 2. Forty patients with tinnitus were treated with ginkgo biloba orally and randomly divided into control and laser groups. The 20 patients of laser group received 80.4 J/cm 2 of 830 nm laser, 3 times per week for 4 weeks, via transmeatal irradiation. Tinnitus was evaluated by visual analogue scale (VAS) and tinnitus handicap inventory (THI). Results: 1. Preventive effect of LLL to gentamicin induced vestibular ototoxicity was demonstrated by preventing reduction of gain in slow harmonic acceleration test and modulation in the off-vertical axis rotation test. 2. Eleven of 20 laser group patients have shown significant improvement in VAS and THI compared to those of the control group. Conclusions: 1. LLL therapy may have preventive effect to vestibular ototoxicity. 2. LLL therapy in combination with ginkgo biloba seems to be worth trying on patients with tinnitus.

Effect of low-level laser treatment on cochlea hair-cell recovery after acute acoustic trauma

“…According to our prior study, the transtympanic penetration rate of laser light into the cochlea was 5.5% in rodents and 2.8% in humans. 40 Since the power of the laser was 100 to 165 mW∕cm 2 at the end of the optic fiber, the energy that reached the cochlea in our study is presumed to be around 5.5 to 9.1 mW∕cm 2 . In order to deliver the same amount of energy in the human cochlea, a much stronger laser will be needed.…”

Efficacy of Low-Level Laser Therapy for Tinnitus: A Systematic Review with Meta-Analysis and Trial Sequential Analysis

“…One study used a low laser device with an intensity of 100 mW and a wavelength of 650 nm for ten sessions [1], one used the device with an intensity of 5 mV and a wavelength of 650 nm for twenty sessions [25], one used the device with an intensity of 5 mW and a wavelength of 650 nm for twenty sessions [26], one used the device with an intensity of 5 mW and a wavelength of 650 nm for seventy sessions [27], two used the device with an intensity of 5 mW and a wavelength of 650 nm for ninety sessions [28,29], one used the device with an intensity of 5 mW and a wavelength of 650 nm for seven sessions [23], one used the device with an intensity of 67 mW and a wavelength of 830 nm for twelve sessions [30], one used the device with an intensity of 60 mW and a wavelength of 810 nm for four sessions [24], and one used the device with an intensity of 50 mW and a wavelength of 830 nm for fifteen sessions [31]. Five studies enrolled patients with SNHL [1,24,26,28,32], whereas four studies included patients with idiopathic tinnitus [25,27,30,31], and the other two studies included patients with mixed tinnitus involving hearing loss and idiopathic tinnitus [23,29]. Nine of the included studies enrolled patients with tinnitus lasting for more than 6 months [23,[25][26][27][28][29][30][31][32], while one study enrolled patients with tinnitus lasting for more than three months [1] and the other one did not report the duration [24].…”

“…Five studies enrolled patients with SNHL [1,24,26,28,32], whereas four studies included patients with idiopathic tinnitus [25,27,30,31], and the other two studies included patients with mixed tinnitus involving hearing loss and idiopathic tinnitus [23,29]. Nine of the included studies enrolled patients with tinnitus lasting for more than 6 months [23,[25][26][27][28][29][30][31][32], while one study enrolled patients with tinnitus lasting for more than three months [1] and the other one did not report the duration [24]. Ten of the included studies performed sham laser as placebo intervention [1,[23][24][25][26][27][28][29]31,32], while the other one did not state the intervention in control group [30].…”

“…Nine of the included studies enrolled patients with tinnitus lasting for more than 6 months [23,[25][26][27][28][29][30][31][32], while one study enrolled patients with tinnitus lasting for more than three months [1] and the other one did not report the duration [24]. Ten of the included studies performed sham laser as placebo intervention [1,[23][24][25][26][27][28][29]31,32], while the other one did not state the intervention in control group [30]. Five of the included studies performed laser unilaterally [1,23,25,28,31], while the other studies did not further report the treatment laterality [24,26,27,29,30,32].…”

“…Ten of the included studies performed sham laser as placebo intervention [1,[23][24][25][26][27][28][29]31,32], while the other one did not state the intervention in control group [30]. Five of the included studies performed laser unilaterally [1,23,25,28,31], while the other studies did not further report the treatment laterality [24,26,27,29,30,32]. Tinnitus severity and improvement were measured immediately after intervention in eight studies [1,[25][26][27][28][29]31,32], while one study measured tinnitus severity two weeks after the intervention [23], and two measured tinnitus severity one week after the intervention [24,30].…”