14 September 2006

Early lapses warn of Alzheimer's

Older adults who complained of recurrent memory loss had brain changes that mirrored those of very early Alzheimer's, a new study reports.

Older adults who complained of recurrent memory loss had brain changes that mirrored those of very early Alzheimer's - even when standard cognitive tests came up normal, a new study reports.

Based on these findings, "cognitive complaints should be taken very seriously - these are not necessarily just the 'worried-well,'" said researcher Andrew Saykin, a professor of psychiatry and radiology at Dartmouth Medical School, in Lebanon, N.H. "Those with significant cognitive complaints and concerns should talk with their physicians and get a thorough evaluation."

The findings were published in the September issue of Neurology. Saykin's team studied 120 adults aged 60 to 90 to determine whether grey matter changes in the brain's medial temporal lobe were similar to those seen in patients with Alzheimer's disease and mild cognitive impairment (very early Alzheimer's).

The study included 40 participants with "cognitive complaints" - including occasional but troublesome forgetfulness - who tested as normal on standard neuropsychological tests. The researchers compared these participants' brain changes to those of 40 patients with mild cognitive impairment and 40 healthy controls, using high-tech MRI brain scans.

Grey matter loss
"The cognitive-complaint and mild-cognitive-impairment groups had similar patterns of decreased gray matter in their brains," Saykin said. "The degree of gray matter loss was associated with the extent of memory complaints and performance deficits," he added.

One expert said the study is interesting because it could point to the early detection of Alzheimer's disease. "I'm excited (about the study) because this is the kind of early diagnostic method that is badly needed. Everything we're doing now says the therapy works better earlier," said Greg M. Cole, associate director of the University of California, Los Angeles' Alzheimer's Disease Research Center.

He said the study provides further evidence that there's a continuum of Alzheimer's-type physical changes in the brain. The findings echo those of another study of older adults, published in Neurology in June. In that research, a team at Rush University, Chicago, found that episodic memory failure corresponded with signs of early, undiagnosed Alzheimer's in brain tissues examined post-mortem.

Although the findings do point to memory lapses as perhaps indicative of very early Alzheimer's disease, "I wouldn't necessarily look at it as something to be extremely concerned about," Dr Sam Gandy, chairman of the Alzheimer's Association's Medical and Scientific Council told HealthDay at the time. He said the results of the Rush study suggest potential new avenues for early diagnosis and treatment.

Cognitive complaints
Cole noted that occasional "cognitive complaints" - forgetting keys, or failing to remember PIN codes at the bank - do occur, of course, and can be a cause for worry. But age-related forgetfulness can be caused by a variety of conditions, including non-Alzheimer's-related vascular disease, he pointed out.

"This study took a comprehensive look and defined a subset of people who have essentially episodic problems yet do well on tests," Cole said. In other words, their forgetfulness occurred frequently and was noted by loved ones, yet the usual tests showed no obvious problem.

Here, however, "the researchers verified the grey matter changes that indicate disease prior to minimal cognitive impairment," Cole said. "They're clicking back the ability to detect incipient Alzheimer's disease with some better confidence that it's truly Alzheimer's disease."

That could lead to the use of neuro-protective agents five, 10 or 20 years before people meet the diagnostic criteria for Alzheimer's, the experts said, to help delay symptoms. "What needs to be proven is whether they are really catching incipient Alzheimer's disease by then confirming these individuals go on to develop Alzheimer's disease," Cole explained.

Accelerated weight loss a sign
"Any drug aimed at Alzheimer's disease will need to help delay the illness in its earliest stages," Cole said. Another study, this time in the September Archives of Neurology, found that accelerated weight loss may be another sign of very early Alzheimer's disease.

Researchers at Washington State University School of Medicine, St. Louis, tracked the weight of 449 adults without Alzheimer's or related dementia when the study began.

Six years on, the 125 participants who did develop the illness were found to have weighed approximately 8 pounds less upon study entry than participants who remained free of Alzheimer's. Weight loss increased as Alzheimer's symptoms appeared, the researchers noted.

If the findings are supported in other studies, early weight loss may be a factor in spotting people at risk for Alzheimer's, the St. Louis team said. Saykin said early detection may someday be key to a cure, as new treatment breakthroughs emerge over time.

"There is an incredible amount of new information about molecule biology that's been uncovered in recent years. For example, the chemical composition of tangles in the brain are becoming better understood, and vaccines to dissolve the causative agent, beta amyloid, are in clinical trials," he said. -(HealthDayNews, September 2006)

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