engleski

Charles bonnet syndrome in elderly people

When a patient presents with vivid visual hallucinations, a doctor probably considers common diagnoses such as delirium, dementia, psychoses or a drug related condition. Charles Bonnet Syndrome (CBS) is a rare condition in wich people experience complex, persistentor repetitive, stereotyped visual hallucinations in absence of significant neuropsychiatric disease. It is associated with deteriorating of vision and good insight. The majority of patients diagnosed with CBS are elderly probably because of the prevalence of visual impairment in this group. It was first described by Charles Bonnet, a Swiss philosopher and naturalist of his grandfather in 1769 but can often be misdiagnosed. Its prevalence in patients with visual impairment varies from 10% to 15%. The common conditions leading to the syndrome are age related macular degeneration, followed by glaucoma and cataract. These hallucinations, wich are always outside the body, may last from a few seconds to most of the day. They may persist for a few days to many years, changing in frequency and complexity. They have no personal meaning, and many patients can voluntarily modify them or make the image disappear if they close their eyes. The imagery is varied and may include groups of people or children, animals and panoramic countryside scenes. The syndrome can occur in people with normal vision. Some have argued that diagnosis of the syndrome does not exclude or require eye disease or brain lesions and that it could even be due to lesions that are not associated with the visual system. Reduced or absent stimulation of the visual system (deafferentation hypothesis) leading to increased excitability of the visual cortex is one of the hypotheses. Treatments with drugs remain unsatisfactory, with poor evidence for the effcacy of antipsychotics and anticonvulsants. The lesson should therefore read "not all elderly people with visual hallutinations have dementia".

Charles Bonnet Syndrome

Indexed / Abstracted in: Neuroscience Citation Indeks ; EMBASE / Excerpta Medica