A difficulty in recognising familiar odours can underline the development of cognitive impairment in older adults. Mild cognitive impairment is a transition stage between the cognitive changes of normal aging and the more serious problems caused by Alzheimer's disease, and can affect memory, language, attention, reasoning, judgment, reading and writing. According to a research undertaken in Rush University Medical Centre, Chicago, researchers did a 12 item 'scratch and sniff' on 589 older adults and evaluated their mental function as well. The subjects of this research were of an average age of 80 years, with no previous history of mental decline. While monitoring them for a period of five years - involving regular annual check ups, it emerged that out of the 589, 177 i.e. 30 percent developed signs of a mild cognitive impairment. As per the findings, a person who made 4 errors on the odour identification test was 50 percent more likely to develop mild cognitive impairment than a person making 1 error. Such a possibility was predicted after taking account of strokes, smoking habits or other factors that might influence the sense of smell. These results point to not only the transition from mild cognitive impairment to Alzheimer's disease but also the transition from normal mental functioning to a mild cognitive disorder. Therefore, testing the sense of smell in older adults can help in identifying those who are at risk for Alzheimer's disease.
Archives of General Psychiatry,
July, 2007