Musical Ear Syndrome in a Patient with Unilateral Hearing Loss: A Case Report.

BACKGROUND Hearing music that has no source is known as musical ear syndrome, also known as musical hallucinations (MH), and is often associated with hearing impairment. This report is of a 62-year-old man with a 20-year history of unilateral hearing loss and continuous MH. We investigated the neural basis of MH in a subject without any known neurological or psychiatric disorders. CASE REPORT A 62-year-old man had a history of 20 years of symptomatic mild hearing loss accompanied with continuous MH in the form of multiple tones. The MH were unilateral in the left side and much more likely to be experienced as externally located and uncontrollable. He underwent structural and functional magnetic resonance imaging (fMRI). Results indicated increased activity and reduced cortical thickness in multiple cortical areas, such as the prefrontal cortex (PFC) and temporal and limbic regions, indicating complex processing and involvement. CONCLUSIONS The neurological findings indicate differentiated or multiple-area involvement in MH. These morpho-functional changes may represent a neural reorganization causing MH to arise. The altered or activated regions are all related to the processing of emotions and the processing of episodic memory, which has been seen in the MH of schizophrenic patients. This report also highlights that patients with hearing loss may present with continuous MH, and that these patients should not be assumed to have delusions or psychosis, but should be investigated for underlying auditory abnormalities and treated appropriately.