Memory and thinking changes in Alzhemeir’s can be detected 18 years before diagnosis: Study
29 Jun 2015
A scientist from Rush University Medical Center has found that, errors on memory and thinking tests might signal Alzheimer's up to 18 years before the disease could be diagnosed. Kumar B Rajan said the changes in thinking and memory that preceded obvious symptoms of Alzheimer's disease began decades before.
According to Kumar while it was not possible to detect such changes in individuals at risk, ''we were able to observe them among a group of individuals who eventually developed dementia due to Alzheimer's.''
In the study, 2,125 European-American and African-American people from Chicago with an average age of 73 without Alzheimer's disease, underwent given tests of memory and thinking skills every three years for 18 years.
During the study, 23 per cent of African-Americans and 17 per cent of European-Americans developed Alzheimer's disease.
Individuals with a lower overall score on the administered memory and thinking tests had a high risk of developing the disease.
In the first year of the study, subjects with lower test scores were about 10 times more likely to be diagnosed with Alzheimer's disease than people with higher scores, and the odds increased by 10 for every standard deviation that the score was lower than the average.
On the basis of tests completed 13 to 18 years before the final assessments took place, a performance lower by one unit lower the standardised cognitive test score was associated with an 85 per cent greater risk (relative risk of 1.85) of future dementia.
''A general current concept is that in development of Alzheimer's disease, certain physical and biologic changes precede memory and thinking impairment. If this is so, then these underlying processes may have a very long duration,'' Kumar said.
"While we cannot currently detect such changes in individuals at risk, we were able to observe them among a group of individuals who eventually developed dementia due to Alzheimer's," said Rajan, an alumnus of Madras Christian College.
"A general current concept is that in development of Alzheimer's disease, certain physical and biologic changes precede memory and thinking impairment. If this is so then these underlying processes may have a very long duration. Efforts to successfully prevent the disease may well require a better understanding of these processes near middle age," Rajan said.
The online journal Neurology has published the research.
