# 2008 The Authors Journal compilation # 2008 Blackwell Munksgaard

Acta Neuropsychiatrica 2008: 20: 91–95 All rights reserved DOI: 10.1111/j.1601-5215.2007.00255.x

ACTA NEUROPSYCHIATRICA

Case report

Musical hallucinosis: case reports and possible neurobiological models Mocellin R, Walterfang M, Velakoulis D. Musical hallucinosis: case reports and possible neurobiological models. Objective: The perception of music without a stimulus, or musical hallucination, is reported in both organic and psychiatric disorders. It is most frequently described in the elderly with associated hearing loss and accompanied by some degree of insight. In this setting it is often referred to as Ômusical hallucinosis’. The aim of the authors was to present examples of this syndrome and review the current understanding of its neurobiological basis. Method: We describe three cases of persons experiencing musical hallucinosis in the context of hearing deficits with varying degrees of associated central nervous system abnormalities. Results: Putative neurobiological mechanisms, in particular those involving de-afferentation of a complex auditory recognition system by complete or partial deafness, are discussed in the light of current information from the literature. Conclusion: Musical hallucinosis can be experienced in those patients with hearing impairment and is phenomenologically distinct for hallucinations described in psychiatric disorders.

Introduction

Music appears to be a ubiquitous human experience extending across cultures and throughout history it may have even predated language. As the experience of both the production and perception of music is closely allied to emotions, memories, fantasy and imagery, it is not surprising that some disorders of perception involve music. Musical hallucinosis (MH) can be defined as the perception of music without the presence of an external musical stimulus in which the subject maintains insight. It is often reported in elderly populations with acquired deafness (1). Although such experiences may result in the diagnosis of psychiatric illness, careful investigation will often reveal focal or diffuse central nervous system lesions. The authors will describe three cases in which MH were prominent and review the current understanding of the neurobiological basis of this phenomenon. Case 1

The first patient was an 82-year-old married woman residing in an isolated farmhouse with her husband.

Ramon Mocellin1,2, Mark Walterfang1,2, Dennis Velakoulis1,2 1 Neuropsychiatry Unit, Royal Melbourne Hospital, Parkville, Melbourne, Victoria, Australia; and 2 Melbourne Neuropsychiatry Centre, University of Melbourne, Parkville, Melbourne, Victoria, Australia

Keywords: auditory; deafness; hallucinations; hallucinosis; musical Ramon Mocellin, Level 2, John Cade Building, Royal Melbourne Hospital, Victoria 3050 Australia. Tel: 161 3 93428750; Fax: 161 3 93428483; E-mail: [email protected]

She had a past medical history of hypertension and mild bilateral sensorineural deafness for some years. She was not prescribed any medications, did not smoke and never drank alcohol. There was no past psychiatric history or any significant family history. She described a 2-year history of hearing music not experienced by others. Initially, she contacted the police to complain of loud music played by her neighbours. She also insisted her husband drive around the district searching for the source of the music. However, she soon began to feel her experiences were Ôtricks of her imagination’. At this time she sought medical assistance. The content of the hallucinations included familiar songs or hymns, often sung by choir-like male and female voices and accompanied by orchestral music. They could also consist of simple repeated sung phrases such as ÔI love you’. The songs could be initiated by the patient thinking of a song. At times they could echo her thoughts. They never took the form of commands and were never derogatory. She was not distressed by these experiences and enjoyed the songs during the day but they often disturbed her sleep and were worse 91

Mocellin et al. at night. There were no other disorders of perception in other modalities. There were no other features of psychiatric disorder in history or mental state examination. There were no neurological signs apart from mild bilateral sensory neural deafness. She was cognitively intact. Routine blood investigations were unremarkable. Magnetic resonance imaging (MRI) showed numerous areas of high signal on the T2-weighted imaging in the white matter regions, primarily involving the corona radiata bilaterally (Fig. 1A and 1B). A single focus of high signal was seen in the left side of the pons, 3 mm in diameter (Fig. 1C and 1D). Hyperostosis frontalis interna was also seen as an incidental finding. She tolerated trials of atypical antipsychotic agents (olanzapine and amisulpride) and sodium valproate poorly and only listening to recorded music with headphones provided relief. Case 2

The second patient was a 62-year-old single man, who enjoyed surfing or ocean swimming on an almost a daily basis for many years, presented with stereotypic MH. He had a history of severe bilateral ear canal exostosis and mild–moderate

sensorineural deafness. There was no other significant medical history. He was a smoker of both tobacco (20 pack-years) and cannabis (less than 1 g per fortnight) but took no other medication. There was no past psychiatric or relevant family history. He described hearing music he identified as the opening bars of the Jimi Hendrix classic Voodoo Child for 6 months. This occurred almost constantly during the day, and could be triggered by any music or highpitched repetitive sounds. He identified these experiences as originating in his Ôown mind’ from the outset and felt he may be misinterpreting sounds with a familiar tune because of his deafness. He was mostly able to ignore these experiences, but as they worsened at night, he sought help for the resulting insomnia. There were no other neurological symptoms and physical examination was unremarkable. Otoscopic examination revealed severe exostosis of the external auditory canal bilaterally. There were no abnormal mental state findings, in particular, no other psychotic symptoms or disorders of perception in other sensory modalities. Cognitive testing was normal. Routine investigations were unremarkable. MRI scan of the brain showed minor white matter disease (Fig. 2A and 2B). After eliminating a number of possible sources, he was able to link his experience to deafness and sought medical assistance. Surgical treatment of the

Fig. 1. Magnetic resonance imaging (MRI) scans (FLAIR) of brain, Case 1, demonstrating significant white matter disease. A and B refer to the corona radiata bilaterally. C and D refer to a single focus of high signal in the left side of the pons, 3mm in diameter.

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Musical hallucinosis: possible neurobiological models

Fig. 2. Magnetic resonance imaging (MRI) scans of brain (FLAIR), Case 2, demonstrating minor white matter abnormalities only (A and B).

exostosis resulted in the replacement of the MH with simple tinnitus. Further treatment and follow up was declined. In Case 2, it is possible that deafness was again superimposed on a vulnerable substrate (minor white matter changes) and that use of cannabis may have increased the risk of MH. Case 3

The third patient was a 78-year-old widower, living in a residential care facility, who was referred after he reported auditory hallucinations to his concerned family. He had a number of medical problems including, Alzheimer’s disease, ischaemic heart disease, chronic obstructive pulmonary disease requiring nocturnal oxygen and severe osteoarthritis. His current treatment included aspirin, salbutamol, anginine, amlodipine, paracetamol, galantamine and memantine. He had stopped smoking more than 15 years previously and seldom drank alcohol. There was no history of psychiatric disorder or relevant family history. He described hearing pleasant and familiar music, particularly at night. This included a number of familiar hymns, of which he only heard the first few lines, or popular songs from the late 1940s and early 1950s. These were often played at the facility in which he had lived for 5–6 years. He felt these originated from other residents playing records late at night, but was adamant they did not disturb him or prevented him from sleeping. On examination, he was profoundly deaf. There were no other psychotic symptoms or other features suggestive of psychiatric disorder. He performed poorly on cognitive testing with poor short-term memory, language function and visuospatial skills. He had features of a dressing apraxia but no other neurological signs. Investigations revealed mild hyponatremia and vitamin B12 defi-

ciency. MRI scan showed significant global atrophy but no focal lesion. Audiometry revealed profound sensorineural deafness. Appropriate treatment of hyponatremia and B12 deficiency did not change the MH. These caused him no distress and no further treatment apart from the fitting of amplifying hearing aids was undertaken. Although no change in the symptoms resulted, an explanation of the possible underlying mechanisms assisted both family and staff of the facility to care for the man. In Case 3, it can be postulated that end-organ failure (deafness) had been superimposed on a vulnerable central nervous system (CNS) substrate Alzheimer’s Disease (AD) to generate MH.

Discussion

Hallucinations attributed to structural CNS disease are often differentiated by the term Ôhallucinosis’. In general, hallucinosis and hallucinations are usually separated by the nature of the associated insight. Hallucinations in psychiatric disorders are defined by the absence of insight in which the person experiencing the phenomena does not understand it as morbid. In general, those describing hallucinosis have some degree of insight, often being able to comprehend their experiences as Ôtricks of the mind’. This is also well described in visual hallucinosis (2). MH is most commonly seen in persons with hearing loss, advanced age, brain disease, cognitive impairment, female gender and social isolation (1). They are also reported in epilepsy and a variety of localised lesions such as intracerebral haemorrhage (3). Although the relative importance of each of these factors is not understood (4), deafness is one of the most common associations. Some patients 93

Mocellin et al. who initially experience MH have been described as developing auditory hallucinations characteristic of schizophrenia later (5). The underlying neurobiological basis of MH remains unknown. The most compelling model is one of spontaneous activity arising in a de-afferented auditory system, which is then interpreted as an external musical stimulus by a cortical pattern recognition system (6). During normal listening to patterned sound such as music, auditory input is processed by two sequential mechanisms. The pattern is first perceived then encoded into memory or recognised. It is possible that reduced auditory input as a result of deafness allows spontaneous activity within the system. This may take the form of positive feedback between the perception and recognition modules resulting in a percept without a stimulus. This in turn would allow inputs to be misinterpreted or act as triggers for MH (Fig. 3). Functional neuroimaging has suggested some anatomical substrates for this model. While perception of simple sounds may involve primary auditory cortex (Heschl’s gyrus) (7), perception of complex sounds seems to be more widely distributed. The right planum temporale and bilateral frontal areas seem to be involved in the determination of melody (8). The cerebellum and basal ganglia seem to have a role in the processing of rhythmic sound (9). Lesions in the brainstem (10,11), either hemispheres (12) and the occipital lobe (13) have been reported in MH. However, multiple vascular lesions

suggested by white matter hyperintensities on neuroimaging are also common associations (4,14). The presence of central vascular lesions may represent the additional risk factor that distinguishes patients with MH from those with deafness without these symptoms. It is possible that vascular lesions may disconnect afferent inputs or cortical networks, increasing the threshold for spontaneous activity. The wide variety of the nature and location of lesions in the auditory system that may result in MH mirrors the heterogeneous lesions associated with complex visual hallucinations (2). These theoretical constructs can aid an understanding of the generation of symptoms in the cases presented. It is possible that the symptoms in Case 1 can be understood in terms of a new pontine lesion superimposed on an abnormal substrate (extensive white matter disease) in the context of end-organ failure (deafness). In Case 2, it is likely that deafness was again superimposed on a vulnerable substrate (minor white matter changes) and that use of cannabis may have increased the risk of MH. Last, it can be postulated that end-organ failure (deafness) had been superimposed on a vulnerable CNS substrate (AD) to generate MH in Case 3. Unfortunately, there is little evidence available to guide treatment apart from the appropriate treatment of the underlying lesion. Pharmacological treatments are usually ineffective; most authors recommend audiological assessment and appropriate amplification (5) when deafness is the trigger. Prognosis is usually guarded with MH persisting and worsening as deafness progresses. Evolution to auditory hallucinations of spoken words and paranoid delusions characteristic of late onset schizophrenialike illnesses have also been reported (15).

References

Fig. 3. Possible mechanisms involved in the normal processing of complex sound (left of dotted line). Deafness (right of dotted line) may result in spontaneous activity and subsequent feedback generating aberrant pattern recognition and musical hallucinosis (see text).

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Musical hallucinosis: possible neurobiological models 7. GRIFFITHS TD, BUCHEL C, FRACKOWIAK RS, PATTERSON RD. Analysis of temporal structure in sound by the human brain. Nat Neurosci 1998;1:422–427. 8. ZATORRE RJ, EVANS AC, MEYER E. Neural mechanisms underlying melodic perception and memory for pitch. J Neurosci 1994;14:1908–1919. 9. PENHUNE VB, ZATTORE RJ, EVANS AC. Cerebellar contributions to motor timing: a PET study of auditory and visual rhythm reproduction. J Cogn Neurosci 1998;10: 752–765. 10. MURATA S, NARITOMI H, SAWADA T. Musical auditory hallucinations caused by a brainstem lesion. Neurology 1994;44:156–158.

11. SCHIELKE E, REUTER U, HOFFMANN O, WEBER JR. Musical hallucinations with dorsal pontine lesions. Neurology 2000;55:454–455. 12. DOUEN AG, BOURQUE PR. Musical auditory hallucinosis from Listeria rhombencephalitis. Can J Neurol Sci 1997;24:70–72. 13. NAGARATNAM N, VIRK S, BRDAREVIC O. Musical hallucinations associated with recurrence of a right occipital meningioma. British J Clin Pract 1996;50:56–57. 14. STEPHANE M, HSU LK. Musical hallucinations: interplay of degenerative brain disease, psychosis, and culture in a Chinese woman. J Nerv Ment Dis 1996;184:59–61. 15. BABA A, HAMADA H. Musical hallucinations in schizophrenia. Psychopathology 1999;32:242–251.

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Musical hallucinosis: case reports and possible neurobiological models.

The perception of music without a stimulus, or musical hallucination, is reported in both organic and psychiatric disorders. It is most frequently des...
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