[Musical hallucinations: 7 cases].

Musical hallucinations (MH) occurred in 7 patients (5 women and 2 men, age 58-90 yrs) with mild to severe unilateral or bilateral deafness. The hallucinations usually consisted of musical memories (childhood songs, past "hits"). They started abruptly and were identified, sometimes after a period of doubt, as hallucinations. They became "louder" in the silence and, when iterative, could be distressing. By concentrating, 3 patients could change the ongoing tune for another. Elementary (1 case) or verbal (3 cases) auditory hallucinations could be associated and, in one case, vivid visual hallucinations occurred which were not criticized. One patient suffered depression and the MH faded after antidepressive treatment. In the other cases, no psychiatric disorder was identified. Neurological examination, EEGs and brain MRI (in 5 cases) were normal in all but one case, in which MH followed seizures secondary to a left parietal metastasis. Such MH may be termed hallucinosis according to Ey's description. They share some characteristics with other hallucinatory phenomena associated with sensory deprivation, such as the Charles Bonnet syndrome and "pain memories" in phantom limbs. However, the role of deafness, the underlying central mechanisms and psychological factors are poorly understood.