Mental exercise thwarts Alzheimer's initially, but hastens cognitive decline later

Do mental exercises to keep the brain running. At least it has always been thought of like that. New research however warrants a re-look at this popular notion.

The latest findings partially corroborate with prior research that states mental activity slows decline in memory in normal old age.

The newest findings also reveal that these very mentally stimulating activities hasten the mental decline once symptoms of dementia set in.

"We think there's a trade-off," said Robert Wilson, lead author of the study and a senior neuropsychologist at the Rush University Medical Center in Chicago.

The study
Being mentally active essentially means that there is "a little more time during which the person is cognitively competent and independent and a little less time in a disabled and dependent state" once dementia does set in.

For the purpose of the study, Wilson and his colleagues examined 1,200 older individuals over a 12 year period.

A 5-point "cognitive activity" scale was devised by the team to assess each participant’s involvement in mentally stimulating pursuits.

At the start of the study, none of the participants had dementia. By the end of the study the number of people who were completely free of dementia stood at 614.

395 of the participants were reported with mild cognitive impairment while 148 had contracted Alzheimer's disease by the end of the study.

The study established that activities like listening to the radio, watching TV, reading helped participants thwart cognitive decline over several years.

On the contrary, in cases where participants indulged in mentally challenging activities but went on to develop dementia, the rate of mental decline was quicker after the illness set in.

Presence of plaques and tangles
The researchers attributed the phenomenon to the amassing of neurodegenerative lesions called plaques and tangles in the brains of patients with dementia.

"The person who has a history of being cognitively active actually has more of the pathology in their brain, and so really has more severe disease. That's why they decline more rapidly from that point on," Wilson opined.

"The results do suggest that mental exercises help stave off dementia but then increase mental decline after dementia onset," said Charles Hall, professor of neurology at Albert Einstein College of Medicine.

The findings of the study have been published online Sept. 1 in the journal 'Neurology.'