Patient on Natalizumab for Multiple Sclerosis: “Earworms or Musical Hallucinations?”

Background: Repetitive music, consisting of “catchy tunes”, which is spontaneously perceived without an external stimulus is a common phenomenon. The term “earworm” derived from the German word “Ohrwurm” has been used to describe the existence of segments of lyrics that are replayed in the mind for short periods of time.

Objectives: Musical and auditory hallucinations are well described in certain neurological and psychiatric diseases. Musical hallucinations due to neurological disease have previously been mentioned in the literature mainly as case reports. Common causes include focal brain lesions, epilepsy, hearing impairment and intoxication. Hallucinations may occur in 10% of MS patients as neuropsychiatric manifestations of the disorder or as a consequence of medications.

Methods: The patient is a 54 years old right handed woman with onset of symptoms related to multiple sclerosis 30 years ago. Due to suboptimal response with platform therapy and non-compliance, the patient was started on natalizumab in March 2010. She noticed progression in her disease a year after treatment was initiated. April 2011, she also became aware that strange words and pieces of music would occur repeatedly in her mind. No history of hearing loss, epilepsy or psychiatric disease. She did not respond to any treatment. Natalizumab was discontinued and she was treated with intravenous steroids in January 2012.                                                                                                                                                                                                                                          Results: Her mental confusion cleared but there was no improvement in the presence of involuntary words and lyrics in her mind. An analysis of our case brings up the question whether her symptoms are due to “ earworms” or are true musical hallucinations which can arise from different parts of the auditory pathways. The repetitive words and lyrics are suggestive of intrusive thoughts. They seem to arise from inside her head rather than from an external source. She does have insight into the problem, does not recognize triggers and tries to subdue them by different techniques.                Conclusions: Our case seems to be experiencing the phenomenon of  ”sticky music” but with more persistent and complex features. It is possible that our patient with long standing MS and  with demonstrable white matter lesions in the cerebral hemispheres on MRI has experienced a ”deafferentation” in her auditory connections. She may be describing musical hallucinations rather than a recurrent “Ohrwurm”. Further work is needed to understand the pathophysiology of musical phenomenon in neurological diseases like multiple sclerosis.