FUNCTIONAL MR SPECTROSCOPY OF THE AUDITORY-CORTEX IN HEALTHY-SUBJECTSAND PATIENTS WITH SUDDEN HEARING-LOSS

PURPOSE: To use MR spectroscopy to study the biochemical changes produ ced by auditory stimuli in patients with sudden sensorineural hearing loss and to compare these findings with the biochemical changes seen i n healthy volunteers. METHODS: Single-voxel MR spectroscopy was used t o study biochemical changes in the auditory cortex in 11 control subje cts and 19 patients with sudden sensorineural hearing loss. MR spectro scopic signals were measured during three different sound conditions ( scanner noise, music, and sirens). RESULTS: A lower MR spectroscopic l actate signal was observed in control subjects during the music stimul us than during the other sound conditions. This music-induced lactate change was not observed in the patients with hearing loss. The other p roton metabolites (choline, creatine, N-acetylaspartate [NAA]) remaine d stable during the different auditory stimuli. However, the NAA/creat ine ratio was higher in the auditory cortex of patients than in the co ntrol subjects, and was not dependent on the sound condition. CONCLUSI ON: The detection of stimulus-induced and stable biochemical MR spectr oscopic changes in patients with hearing loss may be useful in assessi ng disease activity.