Idiopathic clouding of consciousness—do the patients have cortical lewy body disease?

Sixteen out of 58 patients assessed at a day hospital for probable dementia fulfilled the study definition for idiopathic clouding of consciousness. These patients were significantly more likely than other patients in the sample to have visual hallucinations, depression, extrapyramidal symptoms and to experience falls. They hence had the same symptom profile as patients described as having cortical Lewy body dementia, an observation supported by the fact that 14 of the 16 fulfilled McKeith's criteria for the aforementioned condition. Fifty per cent of the patients with idiopathic clouding of consciousness had a family history of Parkinson's disease. The implications of the findings are discussed.