Musical ear syndrome

Musical ear syndrome also known as musical hallucinations or auditory hallucination, is a condition that causes patients with hearing impairment to have non-psychiatric auditory hallucinations characterized by songs, tunes, melodies, harmonics, rhythms, and/or timbres ¹. Hallucinations are usually musical in nature and can range from popular music, orchestral symphonies, or radio tunes without words but a few people have reported that they hear songs with words. In advanced age, musical ear syndrome could be confused with dementia. In addition, musical ear syndrome is suggested to be a variant of Charles Bonnet syndrome (visual hallucinations in visually impaired patients) by some authors ². Although its mechanism is unknown, secondary to hearing loss, phantom sounds are thought to be caused by hypersensitivity in the auditory cortex associated with sensory deprivation ³. Usually, it is experienced by older people with hearing loss and tinnitus, who live alone and may not have the auditory or social stimulation they once had. musical ear syndrome may occur especially when it is quiet, when they are stressed, or if they are taking medications with inconsistent dose management. In these regards, it is worth noting that that musical ear syndrome and auditory hallucination can begin to overlap and merge in the absence of appropriate and sufficient mental health monitoring. Loneliness may be an important factor and increasing social interactions and conversations can be beneficial.

Research by Fukunishi et al. ⁴, Schakenraad et al. ⁵ and Teunisse and Olde Rikkert ⁶ has shown that musical ear syndrome are more common than previously assumed, with prevalence rates of 3.6% among groups of patients referred for audiometric testing. In cochlear implant patients, up to 22 percent of the implantees experienced the musical hallucinations before or after the implant. Musical ear syndrome can occur in people of all ages, with normal hearing, with or without traditional tinnitus and who are not experiencing sudden stress in their life. The majority of the people who have musical ear syndrome have hearing loss. People may think the music is coming from a neighbor’s house or a car sitting outside the house.

Musical ear syndrome can be stimulated by other simple sounds, such as air conditioning or refrigerator motors. People who experience this type of musical ear syndrome insist they feel an associated vibration and hear the voices/music louder when near a vent. Apparently, the brain hears the cyclic nature of these sounds and modifies it into a more complex sound memory. It appears that the brain is so used to hearing sound, that it uses auditory memory to fill the vacuum of the hearing loss.

Although musical ear syndrome is not a “scary” disease, persistant auditory hallucinations or musical hallucinations may disturb patients and affect their quality of life ¹. Patients should be educated about the musical ear syndrome or musical hallucinations and firmly assured that they are not mentally ill. Musical hallucinations can disappear without intervention. Ross ⁷ and Aziz ⁸ found that after the publication of an article on the subject several people wrote to them, and told them that they had adjusted to their musical ear syndrome without seeking any medical attention. However, others show themselves in dire need of medical consultation. Musical ear syndrome can indeed be experienced as mild and well-tolerable, but more often they are experienced as severely disabling, leading to impaired quality of life, significant distress, and comorbid anxiety and/or depression. Patients often have difficulty concentrating and falling asleep, and many of them are afraid that they are dementing or otherwise psychiatrically ill ⁵. Occasionally they develop secondary delusions, and accuse others (frequently neighbors) of being responsible for the music. As a result, they may even call the police, move house, or take other drastic measures. Diagnosis and treatment of such cases is paramount, but at this point the lack of treatment protocols and the lack of knowledge about the natural history and prognosis of musical ear syndrome stand in the way of an evidence-based approach ⁹.

The scientific interest in musical ear syndrome has increased significantly over the past 25 years, but so far no evidence-based treatments have been established ⁹. All pharmacological treatment of idiopathic musical ear syndrome is off-label. It tends to consist of antiepileptics, antidepressants, antipsychotics or acetylcholinesterase inhibitors, but even when treated for a sufficient amount of time and at adequate plasma levels, musical ear syndrome can be refractory to most of these treatments ¹⁰. Haloperidol, atypical neuroleptics, selective serotonin and norepinephrine reuptake inhibitors, and cholinergic and GABAergic agents have been used with some success, along with cognitive behavioral therapy ¹. Experts believe that nondrug treatment options should be preferred to drugs to avoid adverse effects in the elderly population.

Repetitive transcranial magnetic stimulation (rTMS) may perhaps be a viable option in the near future, but so far it only showed a favorable response in a single medication-resistant patient with post-traumatic damage to the right temporal lobe ¹¹..

Musical ear syndrome causes

Musical ear syndrome are commonly divided into two groups. When they occur without the presence of any associated pathological abnormalities—with the exception of hearing impairment (hypoacusis)—they are called idiopathic musical ear syndrome. When there are associated pathological abnormalities, they are named symptomatic musical ear syndrome ¹². The most relevant etiological factors for musical ear syndrome, as reported in the literature, are brain injuries, epilepsy, psychiatric disorder, and intoxication/pharmacology ¹³.

Musical hallucinations, like actual musical sounds, are associated with activity in an extensive network of interconnected brain areas. This network comprises auditory areas, visual areas, basal ganglia, brainstem, pons, tegmentum, cerebellum, hippocampi, amygdala, motor cortex, the peripheral auditory system, and possibly many other areas ¹⁰. Even though there is not a single unique pathophysiological pathway within the network that can be held responsible for the mediation of musical ear syndrome, there is often an etiological factor that would seem to act as a necessary and sufficient condition for it to become activated.

Table 1. Main causes of musical ear syndrome

Main etiology	N	Percentage (%)
Hypoacusis	96	34.8
Psychiatric disorder	63	22.8
Brain lesion or other pathology e.g.,  cerebrovascular cause, tumor, multiple sclerosis and Parkinson’s disease	40	14.5
Epilepsy	12	4.4
Intoxication/pharmacology	63	22.8
None of the above	2	0.7
Total	276	100

[Source ⁹ ]

List of drugs that cause musical ear syndrome

It is worth mentioning that in the intoxication/pharmacology group many causative medications play a role that have an opposite effect to medications used for treatment. Dopamine agonists (causative) and antipsychotics (treatment) work on the same dopaminergic receptors. Anticholinergics and tricyclics (causative) and acetylcholinesterase inhibitors (treatment) act on the same cholinergic neurotransmitters. Benzodiazepines, which act on the gamma-amino-butyric-acid (GABA) system, can at once be causative and curative. This suggests that all the neurotransmitter systems and receptors involved can play an a priori unpredictable role in the mediation and treatment of musical ear syndrome, and that proper clinical and pharmacological assessment is always necessary to establish the course of action that is most likely to yield favorable results.

Benzodiazepines

• lormetazepam
• temazepam
• lorazepam
• triazolam

Opioids

• morphine
• tramadol
• oxycodone

Tricyclic antidepressants

• imipramine
• clomipramine
• mirtazapine

Anticholinergic medication

• biperiden

Alcohol

N-methyl-D-aspartate antagonist

• amantadine

Dopamine agonist

• bromocriptine

Salicylates 

Dipyridamole

Propranolol

Voriconazole

Pentoxifylline

Steroids

Musical ear syndrome treatment

When musical hallucinations are bearable, patients can be reassured without any other treatment. However, in other patients musical hallucinations are so disturbing that treatment is indicated. Distinct etiological groups appear to respond differently to treatment. In the hypoacusis group with patients suffering from idiopathic musical ear syndrome, frequently no treatment is required except for explanation, behavioral interventions, and treating the hearing impairment can yield significant improvement and coping strategies (e.g., more acoustic stimulation) are frequently helpful ⁹. Pharmacological treatment methods can also be successful, with antidepressants being possibly more helpful than antiepileptics, which are still better than antipsychotics ⁹. The limited use of acetylcholinesterase inhibitors has looked promising. Musical hallucinations occurring as part of a psychiatric disorder tend to respond well to psychopharmacological treatments targeting the underlying disorder. Thus, treating musical ear syndrome experienced in the context of a depression with the aid of an antidepressant is more effective than with an antipsychotic, whereas musical ear syndrome experienced in the context of a schizophrenia spectrum disorder tend to respond more often to antipsychotics. Musical hallucinations experienced in the context of brain injuries and epilepsy tend to respond well to antiepileptics, but their natural course is often benign, irrespective of any pharmacological treatment, especially after a stroke. When intoxication/pharmacology is the main etiological factor, it is important to stop or switch the causative substance from a different pharmacological class or medication.

References

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3. Low WK, Tham CA, D’Souza VD, Teng SW. Musical ear syndrome in adult cochlear implant patients. J Laryngol Otol. 2013;127:854–858. http://dx.doi.org/10.1017/S0022215113001758
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