The sound of silence

Abstract

In January, 2011, a previously well 68-year-old woman, presented to our neurology outpatients department with a 6 week history of hearing a male voice singing and gradual bilateral hearing loss over the course of 1 year. The singing started suddenly with songs she knew from her childhood, and more recently she also reported hearing a choir. The singing was perceived as external, heard only in the left ear, and continued all day and night. She reported that the voices were irritating, particularly when trying to sleep. They stopped when she fell asleep and did not interfere with her daytime activities. She had insight that the voices were imaginary but said that she could not “switch them off ” and did not recall any specifi c triggers. There was no alteration of the symptoms with her mood or tiredness. There was no reported change in her mood, with no signs of depression or mania, nor thoughts or intentions of self harm. She did not report tinnitus, other sensory hallucinations, or any symptoms of epileptic seizures such as vacant attacks, odd tastes or smells, incontinence, tongue biting at night, or psychomotor automatisms. She had no history of thought insertion, withdrawal, broadcasting, or any other features of schizophrenia. She had a medical history of hypertension, and was on aspirin, atenolol, and olmesartan. Amitriptyline was prescribed for insomnia. She did not smoke, drink alcohol, or use recreational drugs. On examination she was anxious, but alert and oriented with no cognitive impairment. A full mini-mental state examination could not be done because her hearing loss made the repetition of a sentence impossible. However, she scored 27/27 points on the incomplete test. She was oriented in time, person, and place, with no evidence of alteration of consciousness. She had bilateral hearing loss. Neurological examination was unremarkable other than absent vibration sensation and ankle refl exes. Routine blood tests were normal. An electroencephalogram done whilst she was experiencing the singing, did not show epileptic activity or any other focal or generalised brain abnormalities. CT of the head was normal. MRI of the head (with T1, T2, and FLAIR sequences) showed only a few white matter hyper intensities of the T2 and FLAIR sequences, which can be associated with smallvessel disease secondary to hyper tension. Ear, nose, and throat examination and pure tone audiogram showed bilateral sensorineural hearing loss only. Psychiatric assessment ruled out the possibility of mental illness. Our patient was diagnosed with musical ear syndrome because there was no evidence of neurological or psychiatric disease. This is a syndrome comparable to Charles Bonnet Syndrome in which people with visual impairment have visual hallucinations. Our patient was reassured about the benign nature of her condition. Multiple anticonvulsants were tried with mixed results. In February, 2012, at last follow-up, she had marked improvement of her symptoms after starting Clonazepam. Charles Bonnet was a Swiss scientist who documented complex visual hallucinations in his blind but otherwise healthy grandfather in 1760. Later the blind Charles Bonnet also had similar hallu cinations. Diagnostic criteria have since been developed for the disorder fi rst described as Charles Bonnet Syndrome by a Swiss neurologist George de Morsier, in 1967. Clinical features are often stereotyped, complex visual hallucin ations in a partially sighted patient. The patient has insight that the hallucinations are not real, and there is no psychosis, neurological or cognitive impairment, intox ication, or metabolic abnormality. No other sensory hallu cinations should be present. Generally the hallucinations are self limiting. No clear evidence for treatment exists. The mechanism of Charles Bonnet Syndrome is poorly understood. Few reports about complex auditory hallucinations in people with hearing impairment exist; however, some have suggested that they are quite common. Whether the diagnostic criteria of Charles Bonnet Syndrome should be extended to include complex auditory hallucinations, or these considered separately as Musical Ear Syndrome, is debatable. Our patient’s case is a reminder that hallucinations are not always due to delirium or to psychological or neurodegenerative conditions. Other conditions, such as Charles Bonnet Syndrome or musical ear syndrome, should also be considered.