Memory tests predict brain atrophy and Alzheimer's disease
Data from the Alzheimer's Disease Neuroimaging Initiative (ADNI), involving 230 cognitively normal individuals and 394 individuals with diagnosed with MCI on the basis of one episodic test, has found that performance on two tests markedly improved the identification of those whose MCI was more serious.
MCI can be a step on the road to Alzheimer's, but it can also be a reversible condition, and it’s obviously helpful to be able to distinguish the two.
The study compared those with MCI whose memory performance was impaired only in one (story recall) or two (story recall and word list recall) tests. Those who performed poorly in both showed Alzheimer's biomarkers in the cerebrospinal fluid that more closely resembled Alzheimer's patients than those who only did poorly in one test. Moreover, they showed faster brain atrophy in the medial temporal lobes.
Alzheimer's disease was diagnosed within the three-year study period in around half of the participants who performed poorly in both tests, but in only 16% of those with a poor performance on one test.
Clock drawing test should be done routinely in patients with high blood pressure
An Argentinian study involving 1,414 adults with high blood pressure has concluded that the clock drawing test for detecting cognitive dysfunction should be conducted routinely in patients with high blood pressure
A higher prevalence of cognitive impairment was found with the clock drawing test (36%) compared to the MMSE (21%). Three out ten patients who had a normal MMSE score had an abnormal clock drawing result. The disparity in results between the two tests was greatest in middle aged patients.
The clock drawing test is particularly useful for evaluating executive functions, which are the cognitive function most likely to be damaged by untreated high blood pressure.
The clock drawing test involves being given a piece of paper with a 10 cm diameter circle on it, and having to write the numbers of the clock in the correct position inside the circle and then draw hands on the clock indicating the time "twenty to four".
The average blood pressure was 144/84 mmHg, average age was 60 years, and 62% were women.
The findings were presented at ESC Congress 2018.
Repeated cognitive testing can mask early signs of dementia
Those suspected of cognitive impairment often undergo repeated cognitive testing over time — indeed it is the change over time that is most diagnostic. However, most cognitive functions get better with practice. A new study involving 995 middle- to late-middle-aged men has found that, indeed, there were significant practice effects in most cognitive domains, and diagnoses of MCI doubled from 4.5 to 9% after correcting for practice effects.
Verb fluency helpful in detecting early cognitive impairment and predicting dementia
A large study involving 1820 adults (44+), of whom 568 were cognitively healthy, 885 had MCI, and 367 mild Alzheimer's, found that verb fluency worsened at each stage of cognitive decline, and worse scores in verb fluency task were significantly related to development of MCI, and progression from MCI to dementia. Worsening verb fluency was also associated with a faster decline to MCI, but not to faster progression from MCI to dementia.
Most previous research with word fluency has used category and letter fluency tasks (which demand generating names) rather than verb fluency, but verb fluency is more cognitively demanding than generating names, and may thus be a more sensitive tool.
Effectiveness of brief, simple test to screen for MCI
A brief, simple number naming test has been found to differentiate between cognitively healthy older adults and those with MCI or Alzheimer's.
The King-Devick (K-D) test is a one- to two-minute rapid number naming test that has previously been found useful in the detection of concussion, as well as in detecting level of impairment in other neurological conditions such as Parkinson's disease and multiple sclerosis. The K-D test can be quickly administered by non-professional office staff on either a tablet (iPad) or in a paper version.
The test accurately distinguished the controls from the cognitively impaired individuals more than 90% of the time.
The study involved 206 older adults, including 135 cognitively healthy individuals, 39 people with MCI, and 32 Alzheimer's patients.
The test will need to be validated in larger samples.
Not being aware of memory problems predicts onset of Alzheimer's
A number of studies have shown that people’s own subjective impressions of memory problems should not be discounted, but they shouldn’t be given too much weight either, since many people are over-anxious nowadays about their prospects of dementia. But there is a further complication to this issue, which is that being unaware of one’s own memory problems is typical of Alzheimer's.
Anosognosia is the name for this condition of not being able to recognize one’s memory problems.
A study involving 450 patients who experienced mild memory deficits, but were still capable of taking care of themselves, assessed this awareness by asking both the patients and their close relatives about the patient’s cognitive abilities. Anosognosia was diagnosed when a patient reported having no cognitive problems but the family member reported significant difficulties.
The study found that those suffering from anosognosia had impaired brain metabolic function and higher rates of amyloid deposition. Two years later, they were more likely to have developed dementia.
A study involving 1,062 older adults (55-90), including 191 people with Alzheimer's disease, 499 with MCI and 372 healthy controls, found that those with anosognosia had reduced glucose uptake in specific brain regions. Glucose uptake is impaired in Alzheimer's disease.
Cognitive test differentiates between Alzheimer's and normal aging
The hippocampus, one of the earliest brain regions affected in Alzheimer's, has a number of important memory functions. One of these is relational memory — the hippocampus can bind together pieces of information stored in different parts of the brain, so that, for example, you can remember the name when you see the associated face.
A new cognitive test that assesses relational memory has been found to be effective in distinguishing cognitive impairment that reflects very early mild Alzheimer's from normal aging.
The test involves a circle divided into three parts, each having a unique design. After studying a circle, participants needed to pick its exact match from a series of 10 circles, presented one at a time.
People with very mild Alzheimer's disease did worse overall on the task than those in the healthy aging group, who, in turn, did worse than a group of young adults. Moreover, those with Alzheimer's were particularly susceptible to interference from intervening lure stimuli. Including this in the analysis improved the test’s ability to differentiate between those who did and those who did not have Alzheimer's. It also provides evidence that Alzheimer's is qualitatively different from normal age-related cognitive decline, not simply an extension of it.
The study involved 90 participants, including 30 young adults, 30 cognitively healthy older adults, and 30 with very early Alzheimer's.
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