Nov. 27, 2000 -- Dementia that occurs later in life, like Alzheimer's disease, may show up far earlier in the form of slightly reduced mental ability, according to Scottish researchers, whose study is published in the Nov. 28, 2000 issue of the journal Neurology. But, other experts debate their conclusions.
The term dementia refers to any and all medical conditions, usually occurring in old age, that lead to deterioration of the mental capacity of the brain, resulting in symptoms that include memory loss, disorientation, and confusion. Alzheimer's disease is probably the best known form of dementia.
Now, researchers led by Lawrence Whalley, MD, from the department of mental health at Aberdeen University and the Clinical Research Center of Royal Cornhill Hospital in Scotland, have found a link between reduced mental ability in 11-year-old children and the risk of having dementia after age 65.
According to the researchers, the most intriguing implication of these findings is that although some forms of dementia may not be clearly apparent until after age 64, very early signs of the condition show up in childhood in the form of slightly reduced mental ability.
However, there are several other possible explanations for the findings. James Ellison, MD, MPH, tells WebMD that children who have poor mental ability early in life are less likely to go on to attain high educational and occupational levels. Ellison, who is director of geriatric psychiatry at McLean Hospital in Belmont, Mass., and an associate clinical professor of psychiatry at Harvard Medical School, explains that low educational and occupational statuses are both associated with poor health habits, including eating poorly and smoking, which in turn have been linked to certain kinds of dementia.
According to neurologist Marc L. Gordon, MD, MPH, the study also reinforces the commonly held 'use it or lose it' theory of Alzheimer's disease, which states that 'exercising' your brain with intellectual activity offers protection against the condition. He says that the higher their mental ability, the more likely people are to use their brains at school and at work.
Other possible interpretations Gordon offers are that people with elevated mental ability have a longer way to decline before they develop the mental problems associated with dementia or that people with lower mental ability have brains that are more vulnerable to degenerative diseases like Alzheimer's. Gordon is chief of neurology at the Hillside Hospital division of the Long Island Jewish Medical Center and an assistant professor of neurology and psychiatry at Albert Einstein College of Medicine in New York.
Ellison cautions against panic in parents. "If your child does poorly on an intellectual or achievement test," he says, "it does not mean the child is destined to go on and develop dementia. ... [Rather, this study suggests that] the development of a dementia reflects a process that spans over a period of years, which means there are opportunities to intervene with diet, lifestyle, and medications." He points out that the authors of the study looked only at the averages of groups of intelligence scores, which does not allow for drawing conclusions about individual children.