Cognitive Impairment Test: for Risk of Future Development of Alzheimer's Disease (AD)
The early symptoms of Alzheimer's disease (AD) may be overlooked because they resemble signs of natural aging. Older adults who begin to notice a persistent mild memory loss of recent events may have a condition called mild cognitive impairment (MCI). MCI is now believed to be a significant sign of early-stage Alzheimer's in older people. Studies now suggest that older individuals who experience such mild memory abnormalities can later develop Alzheimer's disease.
The disorder can be divided into two broad subtypes. Amnestic MCI significantly affects memory, while nonamnestic MCI does not. Other functions, such as language and attention span, may be impaired in either subtype.Amnestic MCI has been linked to Alzheimer's disease, while nonamnestic MCI may progress to other types of syndromes — such as frontotemporal dementia, primary progressive aphasia or dementia with Lewy bodies. But some people with MCI don't go on to develop any type of dementia. Some remain stable, while others even revert to normal.
Alzheimer's disease (AD), also known simply as Alzheimer's, is a neurodegenerative disease characterized by progressive cognitive deterioration together with declining activities of daily living and neuropsychiatric symptoms or behavioral changes. It is the most common type of dementia.
Dementia is generally defined as the ‘loss of intellectual abilities (medically called cognitive function) of sufficient severity to interfere with social or occupational functioning'.Intellectual capability is a complex function consisting of many individual “components”, such as,memory, problem-solving, calculation, speech, ability to find the way, analyze problems, etc.
Components of intellectual capability :
- Memory and learning
- Attention, concentration and
- Thinking (e.g. problem-solving,
- Language (e.g. comprehension,
- word finding)
- Geographic orientation
Sometimes people get very concerned about minor forgetfulness which is completely normal in old age, and confuse it with Alzheimer’s disease.In some people, increasing age is accompanied by a loss of intellectual capability so marked that it becomes a disease. This very rapid decline is shown in the above graph as Alzheimer’s disease.Between the inevitable consequences of ageing and Alzheimer’s disease is the "grey area" (shaded grey in the diagram) in which some people suffer loss of intellectual functions that is more than mild and yet not severe enough to be considered Alzheimer’s disease.
A new study is now underway at the University of Michigan that uses a new imaging compound called Pittsburgh Compound-B (PIB) to visualize the amyloid plaque deposits typically found in the brains of people with Alzheimer’s disease.. Amyloid plaques, along with tangles, are the hallmarks of Alzheimer’s disease that researchers look for at the time of autopsy to confirm the diagnosis. Being able to detect the accumulation of plaques while patients are alive could lead to a much earlier and more accurate diagnosis of Alzheimer’s disease. It is also hoped that if researchers can detect the plaque deposition early on in the course of the disease, they me be able to better monitor the effectiveness of new treatments in ongoing or planned clinical trials. One line of research being studied includes therapies that may be useful in clearing away plaque deposits from the brain.
Magnetic resonance (MR) or computed tomographic (CT) imaging is recommended for the routine evaluation of AD. Coronal MR images can be useful to document or quantify atrophy of the hippocampus and entorhinal cortex, both of which occur early in the disease process. Both volumetric and subtraction MR techniques can be used to quantify and monitor dementia progression and rates of regional atrophy. MR measures are also increasingly being used to monitor treatment effects in clinical trials of cognitive enhancers and antidementia agents. Positron emission tomography (PET) and single photon emission CT offer value in the differential diagnosis of AD from other cortical and subcortical dementias and may also offer prognostic value. In addition, PET studies have demonstrated that subtle abnormalities may be apparent in the prodromal stages of AD and in subjects who carry susceptibility genes. PET ligands are in late-stage development for demonstration of amyloid plaques, and human studies have already begun. Functional MR–based memory challenge tests are in development as well.
The Cognitive Disorders patients should undergo definitive diagnosis and management for people with: memory loss, cognitive impairment due to Alzheimer's disease and related disorders, and other neurodegenerative disorders that affect memory and thinking.
Simple cognitive tests can help predict the likelihood that a person with mild cognitive impairment will progress to Alzheimer's disease (AD), researchers report in the journal Neurology.
Among 539 older individuals with mild cognitive impairment, the overall rate of progression to AD was 16 percent per year during a 36-month study, Dr. Adam S. Fleisher from the University of California, San Diego, and associates report in the journal.
They found that scores on several tests of mainly memory and recall, combined with the person's APOE4 status, was 81 percent accurate in predicting progression from mild cognitive trouble to AD. APOE4 gene variant is well known to be associated with an increased risk of developing Alzheimer's disease.
A second paper in Neurology identifies symptoms associated with progression to AD.
Dr. Katie Palmer and colleagues at the Karolinska Institute in Stockholm, Sweden, investigated whether mood- and motivation-related depressive symptoms and anxiety in 185 individuals with mild cognitive impairment were related to the future development of AD.
Although depressive symptoms were not associated with an increased risk of progressing from mild cognitive impairment to full blown AD, the authors report, each increasing number of anxiety symptoms nearly doubled the risk of progressing to AD.
The risk of progression to AD was also increased significantly in those reporting problems with decision making and in those with persistent worrying, the researchers note.
Among elderly persons without cognitive impairment, the report indicates, the risk of AD nearly doubled with each increasing number of mood-related depressive symptoms.
Elderly patients presenting with both anxiety and memory problems should be closely followed and monitored, "as there is a very high risk that they will develop Alzheimer's disease within three years," Palmer told Reuters Health.