Diagnosing early cognitive decline in dementia from home

An international team of scientists have developed a new way to screen for age-related cognitive decline at home using a test which asks people to detect sounds and flashes on their laptop or phone.

The study shows that the simple, cost-effective test may be used to help improve early diagnosis of Mild Cognitive Impairment (MCI) and provide interventions as early as possible. This is particularly relevant given that MCI can develop into Alzheimer's disease in 30 to 50 percent of people. The study is published in Scientific Reports.

There are currently no diagnostic blood tests like those for diabetes for MCI, and instead the existing diagnosis involves lengthy neuropsychological assessments with tests of cognitive control and memory, along with questions about daily activities and mood. These costly tests require training, often take a lot of patient and clinician time, and can be impacted by factors such as the individual's IQ, socio-economic status and even the testers themselves. As a result, with an ageing global population, and an around 50 million people estimated to be living with dementia worldwide, there is an urgent need for such a test.

As part of the study, the 123 participants were simply asked to press a button whenever they saw a flash of light or heard a sound. At times, the flashes or sounds were presented alone, but at other times the two appeared simultaneously. The participants included 51 healthy young adults, 49 healthy older adults and 23 older MCI adults.

The researchers then extracted two measures about each person's performance: 1) whether they were faster at detecting flashes or sound, and 2) the extent to which they benefited from detecting an auditory-visual event versus either flashes or sounds. Authors explained that by using just these two measures, the team could accurately tell if a person was diagnosed with MCI using standard clinical tests.

The pattern of sensory dominance shifted with healthy and abnormal aging to favor a propensity of auditory-dominant behavior (i.e., detecting sounds faster than flashes). Notably, multisensory benefits were larger only in healthy older than younger individuals who were also visually-dominant. Second, authors demonstrate that the multisensory detection task offers benefits as a time- and resource-economic MCI screening tool.

One of the senior authors said: "We are particularly excited about this work because it shows how very simple tests can help clinical practice by reaching a wider population, at a lower cost. We are happy that our findings clarify the link between our vision and hearing and their role in supporting memory (dys-)function; it becomes increasingly clear that how preserved our cognitive skills are as we age depends on how intact our senses are. This importantly extends our similar existing findings in school-age children."

The team is now designing new ways to validate this new screening tool and exploring the role of neurotransmitter systems in age-related and pathological changes in sensory and cognitive functions to inform early diagnosis and potential treatment options."

https://www.city.ac.uk/news/2018/june/new-screening-tool-could-help-diagnose-early-cognitive-decline-in-dementia-from-home