[Effectiveness of low level laser irradiation on tinnitus and parameters of electrocochleography and distortion product otoacoustic emissions]

Tinnitus is the consciousness of sound that arises in the ear or head without any external sound origin. The efficacies of transmeatal low-level laser irradiation for tinnitus treatment were reported before. The aim of this study was to evaluate the effectiveness of low level laser therapy on tinnitus and ECochG and DPOAEs parameters. The study design was prospective, quasi experimental. This investigation conducted on 16 ears [10 patients] with disabling tinnitus. All patients underwent ENT examination, complete audiological evaluation, tinnitus study, ECochG and DPOAEs, and finally completing tinnitus data sheet. The results were compared before and after irradiation. Means of tinnitus loudness [LMT] and CAP amplitudes were significant different before and after irradiation [p<0.005]. There was no any other significant difference before and after low level laser irradiation in subjective loudness, pitch matching annoyance grade of tinnitus and DPOAEs and other ECochG parameters. Transmeatal low-power laser irradiation with 200 mW seems not to be effective for treatment of tinnitus. This paper is the research brief report. In clinical point of view, this study should be repeated with a greater sample size although our results were statistically important

[Auditory neuropathy: Findings of behavioral physiological and neurophysiological tests]

Auditory neuropathy [AN] can be diagnosed by abnormal auditory brainstem response [ABR], in the presence of normal cochlear microphonic [CM] and otoacoustic emissions [OAEs]. The aim of this study was to investigate the ABR and other electrodiagnostic test results of 6 patients suspicious to AN with problems in speech recognition. This cross sectional study was conducted on 6 AN patients with different ages evaluated by pure tone audiometry, speech discrimination score [SDS], immittance audiometry. ElectroCochleoGraphy, ABR, middle latency response [MLR], Late latency response [LLR], and OAEs. Behavioral pure tone audiometric tests showed moderate to profound hearing loss. SDS was so poor which is not in accordance with pure tone thresholds. All patients had normal tympanogram but absent acoustic reflexes. CMs and OAEs were within normal limits. There was no contra lateral suppression of OAEs. None of cases had normal ABR or MLR although LLR was recorded in 4. All patients in this study are typical cases of auditory neuropathy. Despite having abnormal input, LLR remains normal that indicates differences in auditory evoked potentials related to required neural synchrony. These findings show that auditory cortex may play a role in regulating presentation of deficient signals along auditory pathways in primary steps