Cognitive Decline Begins Years Before Alzheimer Diagnosis

Carriers of the PSEN1 E280A mutation, a gene associated with autosomal dominant Alzheimer disease (ADAD), can experience cognitive decline 12 years before the onset of clinical impairment and 17 years before a diagnosis of dementia, according to a new study.

To investigate the onset and severity of cognitive decline in those who are most susceptible, researchers analyzed data from 493 carriers of the mutation gene from the Consortium to Establish a Registry for Alzheimer Disease test battery in Antioquia, Colombia, from 1995 to 2012.
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Participants were assessed based on memory, language, praxis, and total scores. The majority of participants were women, were married, had a low socioeconomic status, and had a mean education of 7.2 years.

After analyzing the data in 2015, researchers found that cognitive decline started 12 years before clinical impairment and 17 years before dementia diagnosis when compared with their relative’s dementia onset age. Word list recall scores were an early indicator of decline, they noted.

Although age of dementia onset was delayed by 3 years in those with higher education levels, they experienced a 36% increased rate of cognitive decline after dementia onset than those with lower education levels.

“Preclinical cognitive decline was evident in PSEN1 E280A mutation carriers 12 years before the onset of clinical impairment,” researchers concluded. “Educational level may be a protective factor against the onset of cognitive impairment.”

—Amanda Balbi

Reference:

Aguirre-Acevedo DC, Lopera F, Henao E, et al. Cognitive decline in a Colombian kindred with autosomal dominant Alzheimer disease: A retrospective cohort study. JAMA Neurol. Published online February 22, 2016. doi:10.1001/jamaneurol.2015.4851.