Alzheimer’s diagnostic guidelines released

By Dr. Ananya Mandal, MDApr 19 2011

Neurologists and experts have come up with a set of guidelines to better diagnose Alzheimer's disease in the clinic for the first time in nearly three decades. The advice also helps doctors identify the earliest signs of the degenerative condition, even before symptoms of memory loss begin. The hope is that they can help patients prepare early, and eventually treat, the disease.

The guidelines were released as a draft by the Alzheimer's Association and the National Institute on Aging in June 2010. Not much has changed in the final version.

At present Alzheimer's disease can be definitively diagnosed only at autopsy, when pathologists can confirm the presence of protein plaques and tangles in the brain of a patient who had shown signs of memory loss and cognitive deficits.

The new guidelines differentiate it into three stages of the disease that are meant to help doctors better identify affected patients while they are alive. The phases also reflect the latest research, which suggests that Alzheimer's develops in the brain over a long period of time — perhaps years or even decades before the first cognitive deficits are noticeable.

1. Stage 1, known as preclinical Alzheimer's disease, includes those who are on the road to the neurodegenerative decline typical of the condition. These patients have no signs of any problems yet — they have no difficulty with memory or recall, and remain mentally intact — but in their brains, the protein amyloid is starting to build up. Researchers are working towards developing ways to detect this subtle accumulation using tests.
2. Stage 2 of sorts is called pre-dementia, and encompasses patients who might be showing the first signs of memory lapses, changes in learning or attention, and other deficits in thinking. Otherwise known as mild cognitive impairment (MCI), these symptoms may be noticeable to both the patient and her family and friends, and while obvious, they may not be severe enough yet to cause any problems with daily activities. Not all with MCI will develop Alzheimer's, and the guidelines specify four levels of the condition that can help doctors distinguish which cases are more likely to progress to Alzheimer's and which are not. At this stage brain images may help detect the development of the disease.
3. Stage 3 includes patients with dementia due to Alzheimer's disease; these patients have cognitive deficits that impair a person's ability to function in his daily life. In addition, this stage would include people with genetic mutations linked to the disease, which are responsible for both the early onset condition that runs in families as well as the more common dementia that progresses later in life.

The guidelines recommend diagnostic suggestions for patients with dementia. The aim of the guideline is to make it easier for non-specialists - physicians without access to sophisticated brain imaging instruments or the latest assays for blood or spinal fluid tests - to distinguish the Alzheimer's patient from others suffering from dementia.