In what could lead to a non-invasive tool for early diagnosis of Alzheimer's disease researchers have identified an odour biomarker that can be used to predict the development of the debilitating brain disorder. The odour signature appears in urine before significant development of Alzheimer-related brain pathology the study said. We have evidence that urinary odour signatures can be altered by changes in the brain characteristic of Alzheimer's disease said one of the study authors Bruce Kimball from the US Department of Agriculture (USDA). The odour signature was identified in mouse models of Alzheimer's disease. Because Alzheimer's is a uniquely human