When it comes to the early detection of Alzheimer’s disease, a new study suggests that the nose knows.
Mass General Brigham neurology researchers in the United States have created a smell test that shows promise as a tool for identifying risk of cognitive impairment.
They found that test participants could successfully take the test at home, and that older adults with cognitive impairment scored lower on the test than cognitively normal adults.
Their study on the test could help identify people who are at risk of Alzheimer’s, and help physicians intervene before serious symptoms set in.
“Early detection of cognitive impairment could help us identify people who are at risk of Alzheimer’s disease and intervene years before memory symptoms begin,” said study senior author and neurologist Dr Mark Albers of the Laboratory of Olfactory Neurotranslation, the McCance Center for Brain Health, and Department of Neurology at Massachusetts General Hospital.
“Our goal has been to develop and validate a cost-effective, non-invasive test that can be performed at home, helping to set the stage for advancing research and treatment for Alzheimer’s,” he added.
Early symptoms for Alzheimer’s disease typically appear after age 60, and the risk increases with age.
The researchers’ olfactory tests – which involve participants peeling and then sniffing odours on a card – assess people’s ability to identify and remember odours.
Dr Albers and his colleagues are interested in whether olfactory dysfunction – the sometimes-subtle loss of sense of smell – can serve as an early warning sign for neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, chronic traumatic encephalopathy and traumatic brain injury.
Dr Albers helped found a company that makes the Aromha Brain Health Test, the test used by the research team to conduct this study.
To evaluate the olfactory test, the team recruited English- and Spanish-speaking participants who had self-reported concerns about memory, or those with mild cognitive impairment.
The researchers compared these participants’ test results with those who had no sense of smell and with cognitively normal individuals.
The research team found that odour identification, memory and discrimination declined with age. They also found that older adults with mild cognitive impairment had lower scores for odour discrimination and identification, compared with older adults who were cognitively normal.
Overall, the researchers found that test results were similar across English and Spanish speakers, and participants performed the test equally successfully, regardless of whether they were observed by a research assistant.
The authors noted that future studies could incorporate neuropsychological testing and could follow patients over time to see if the tool can predict cognitive decline.
“Our results suggest that olfactory testing could be used in clinical research settings in different languages and among older adults to predict neurodegenerative disease and development of clinical symptoms,” Dr Albers said.
The number of people living with Alzheimer’s is projected to double from 6.9 million in 2020 to nearly 14 million people by 2060.
Alzheimer’s disease is a top 10 leading cause of death in the US.
The actual number of older people who die from Alzheimer’s may be much higher than what is officially recorded.
This is because Alzheimer’s and other types of dementia are not always reported on death certificates. – By Rick Sobey/Boston Herald/Tribune News Service
