Magnetoencephalographic (MEG) for cases of tinnitus

Abstract

Tinnitus is a hallucinatory sound which is felt in the ear or in the intracranial area. It occurs regardless of the presence or the absence of the source of the sound exterior to the body. It is thought to appear with the disorder of the inner ear, including the sensorineural hearing loss. However, there are several cases for which there is no obvious abnormality of the ear function. These pathoses have not been completely proven. We thought that a functional check of the brain is useful in cases of tinnitus, who demonstrate no abnormal organic findings. Therefore, we examined these cases, which did not have a recognized worsening of auditory acuity and laterality, as assessed by Magnetencelography. With respect to the place in which the dipole occurred upon auditory stimulation, both examples were normal. A shortening of the latency which was induced by the maximum amplitude appearance via auditory stimulation in the magnetic field, was found in two cases. A significant difference was not seen in the tinnitus group versus the mutual intervals of the non-tinnitus group with respect to latency. We examined the association of the latency between the frequency with the audibility threshold, and THI (tinnitus handicap intency) score and the quality of tinnitus expected by the pitch-match test, but these results also did not show any significant differences. Therefore, we thought that the abnormality of the audition perception disposal in the nucleus level or the sound which should not have been heard might occur in tinnitus side. Since tinnitus is a sensation in the whole highly advanced nucleus, it is thought that our approach of a functional check as magnetoencephalogram was useful in the elucidation of pathology of this problem.