Laser Therapy for Tinnitus and Hearing Loss

① It is generally believed that the respiratory chain plays a central role in the effect of laser treatment. Laser energy in the red and near-infrared spectrum is capable of penetrating tissue. It stimulates the mitochondria in cells to produce energy by producing adenosine triphosphate (ATP).

② Mitochondria, which are the power source of all batteries, they metabolize fuel and generate energy for cells in the form of ATP.

③ It has been reported that LLLT exposure increases ATP production. Increased ATP production may lead to increased cellular metabolism, promote recovery from damage, restore cells to a healthy state, and reverse many degenerative conditions.

④For ear diseases, it is reported that low-intensity laser can change the collagen tissue in the cochlea. Especially in the basement membrane. In addition, LLLT has a beneficial effect on the recovery of cochlear hair cells after acute alopecia and can increase the number of cells.

⑤Proliferate, synthesize ATP and collagen, release growth factors, promote local blood flow in the inner ear, and activate the repair mechanism. The inner ear is stimulated by photochemical and photophysical stimulation of hair cell mitochondria.

A total of 107 individuals, comprising both men and women aged between 18 and 65 years, experiencing idiopathic and refractory tinnitus, were enrolled in the study. Recruitment was conducted via online platforms and newsletters, targeting individuals with unilateral or bilateral tinnitus symptoms. Exclusion criteria included endocrine disorders, diabetes, hypertension, cancer, and obesity.

Group 1 (n = 11) received treatment involving vacuum therapy and low-level laser therapy (LLLT). The laser parameters were set to 100 mW for each laser spot, with wavelengths of 660 nm (3 spots; red light) and 808 nm (3 spots; infrared light). Vacuum therapy was applied for 3 minutes around the ear using the MP7 mode (continuous) at a pressure of −120 mbar. Transcochlear administration (i.e., in the post-auricular region) of LLLT and vacuum therapy was carried out using a single device configured appropriately for different settings.

While previous literature has shown positive outcomes of LLLT for tinnitus treatment, studies investigating cochlear LLLT have typically utilized laser power levels <7.5 mW. Contrary to these findings, our study revealed no significant effects when increasing the power to 100 mW per spot for both 660 nm and 808 nm wavelengths, whether combined with vacuum therapy or flunarizine dihydrochloride. Notably, the lack of significance was demonstrated by the absence of statistically significant differences in Total Tinnitus Handicap Inventory (THI) scores between the placebo (Group 1) and treatment groups (Groups 2 and 3).

Although literature on cochlear LLLT using laser power levels >7.5 mW is scarce, such levels are commonly reported in transmeatal LLLT studies. One such study by Shiomi et al. involved 38 refractory tinnitus patients treated with 830-nm transmeatal LLLT via the external auditory canal towards the cochlea using 40 mW of power, once weekly for approximately ten weeks. Following treatment, participants rated tinnitus volume, duration, and discomfort on a five-point scale. While only 26% of patients exhibited improvement in evaluated criteria, improvements of up to 55% to 58% were observed in duration, volume, and annoyance levels, suggesting photobiomodulation as a viable option for rehabilitating patients with refractory tinnitus.