Transmeatal cochlear laser (TCL) treatment of cochlear dysfunction: A feasibility study for chronic tinnitus

Abstract

Low-level-laser-therapy (LLLT) targeting the inner ear has been discussed as a therapeutic procedure for cochlear dysfunction such as chronic cochlear tinnitus or sensorineural hearing loss. Former studies demonstrate dose-dependent biological and physiological effects of LLLT such as enhanced recovery of peripheral nerve injuries, which could be of therapeutic interest in cochlear dysfunction. To date, in patients with chronic tinnitus mastoidal and transmeatal irradiation has been performed without systematic dosimetric assessment. However, light-dosimetric studies on human temporal bones demonstrated that controlled application of laserlight to the human cochlea depends on defined radiator position within the external auditory meatus. This feasibility study first presents a laser application system enabling dose-controlled transmeatal cochlear laser-irradiation (TCL), as well as preliminary clinical results in patients with chronic cochlear tinnitus. The novel laser TCL-system, consisting of four diode lasers (lambda=635 nm-830 nm) and a new specific head-set applicator, was developed on the basis of dosimetric data from a former light-dosimetric study. In a preliminary clinical study, the TCL-system was applied to 35 patients with chronic tinnitus and sensorineural hearing loss. The chronic symptoms persisted after standard therapeutic procedures for at least six months, while retrocochlear or middle-ear pathologies have been ruled out. The patients were randomised and received five single diode laser treatments (lambda=635 nm, 7.8 mW cw, n=17 and lambda=830 nm, 20 mW cw, n=18) with a space irradiation of 4 J/cm2 site of maximal cochlear injury. For evaluation of laser-induced effects complete otolaryngologic examinations with audiometry, tinnitus masking and matching, and a tinnitus-self-assessment were performed before, during and after the laser-irradiation. The first clinical use of the TCL-system has been well tolerated without side-effects and produced no observable damage to the external, middle or inner ear. Changes of tinnitus loudness and tinnitus matching have been described. After a follow-up period of six months tinnitus loudness was attenuated in 13 of 35 irradiated patients, while two of 35 patients reported their tinnitus as totally absent. Hearing threshold levels and middle ear function remained unchanged. Further investigations by large double-blind placebo-controlled studies are mandatory for clinical evaluation of the presented TCL-system and its therapeutic effectiveness in acute and chronic cochlear dysfunction.

Alterations in Auditory Electrophysiological Responses Associated With Temporary Suppression of Tinnitus Induced by Low-Level Laser Therapy: A Before-After Case Series

“…In contrast to the findings of Nakashima et al, 18 Mirz et al, 19 and Teggi et al, 20 we found significant differences for subjective tests consisting of VAS for loudness, LMT, TQ and THI pre-to post-treatment. Consistent with Okhovat et al, 21 Tauber et al, 10 Cuda and De Caria, 14 Hahn et al 24 and Salahaldin et al, 16 an improvement in VAS, THI and reduction in loudness were reported pre-to post-LLLT in subjective descriptions of tinnitus. The efficacy of LLLT for tinnitus suppression according to subjective evaluations has been reported from 0% to 90% in different studies.…”

“…It has been suggested to be effective in treatment of peripheral and central nervous system injuries, musculoskeletal injuries, Buerger disease and sympathetic nervous system dysfunction. [8][9][10] LLL is also used to treat chronic impaired hearing, sudden sensorineural hearing impairment, 11 Meniere disease and some other balance disorders. 12 It has also been reported to decrease tinnitus loudness and annoyance.…”

“…22 It has also been reported to improve local microcirculation through blocking sympathetic nerve action potential and increasing oxygen supply to hypoxic cells. 23 Of the studies that investigated the effects of LLLT on both hearing loss and tinnitus, some found different levels of improvement in hearing thresholds and tinnitus symptoms (Table 1), 10,[13][14][15][16] while others have found no significant effects. [17][18][19] The therapeutic effects of LLL on tinnitus are controversial and findings are inconsistent.…”

Transmeatal Low-Level Laser Therapy for Chronic Tinnitus with Cochlear Dysfunction

“…Tauber et al [2003] described changes in tinnitus loudness and matching. After a follow-up period of 6 months, tinnitus loudness was attenuated in 13 of 35 irradiated patients, while 2 of 35 patients reported their tinnitus as totally absent.…”

Treatments for Tinnitus

“…In his review, Dobie (2004a) reported no beneficial effect from any of these procedures. A subsequent exploratory study used low-powered laser technology (Tauber, Schorn, Beyer, & Baumgartner, 2003) that involved highly defined dose and positioning within the ear canal. Outcomes suggested that this refinement of the laser procedure may have beneficial value, meriting more systematic investigation.…”