What is Alzheimer's Disease?

Scientists aren’t absolutely sure what causes cell death and tissue loss in the Alzheimer's brain, but the plaques and tangles are prime suspects.

Does Memory Loss Always Mean Dementia?

Dementia is a broad category of symptoms that affect the brain and causes memory loss.

Early onset Alzheimer's

Although, Alzheimer’s is viewed as a disease of the elderly, up to 5% of Americans with Alzheimer’s have the early-onset variety, which can start to show symptoms as early as one’s 30s.

Showing posts with label Cognitive decline. Show all posts
Showing posts with label Cognitive decline. Show all posts

Sunday, August 12, 2018

Oral health may be linked to cognitive decline


Oral health cognitive decline

According to new research published in the Journal of the American Geriatrics Society, there may be a link between oral health and the progression of cognitive decline.

"Clinical evidence suggests that the frequency of oral health problems increases significantly in cognitively impaired older people, particularly those with dementia,” said lead researcher Bei Wu, PhD, of Duke University's School of Nursing in Durham, North Carolina in the US.

"In addition, many of the factors associated with poor oral health — such as poor nutrition and systemic diseases like diabetes and cardiovascular disease — are also associated with poor cognitive function,” he added.

The researchers caution, however, that more studies are needed.

Findings came from the first systematic review of studies focused on oral health and cognition. These two important areas of research are important because in a growing older adult population, some 36% of people over age 70 are already living with some degree of cognitive decline. Researchers believe that a common inflammatory pathway may hold the key to a link between oral hygiene and cognitive impairment, if such a link exists.


Poor oral health has been blamed for heart disease, due to the spread of bacteria and oral health problems may be aggravated by diabetes and HIV/AIDS due to reduction of body’s resistance to infection.

Alzheimer's Association estimates around 5.4 million people in the US have Alzheimer's disease - the most common form of dementia.

To look for a link between oral health and cognitive status, Dr. Wu and her colleagues combed through 56 studies published between January1993 and March 2013 that examined the relationship between oral health and change in cognitive health or dementia incidence. They analyzed relevant cross-sectional (data collected at one specific point in time) and longitudinal (data collected over an extended period of time).

Some of the studies analyzed found that dental health measures, such as the number of teeth, the number of cavities, and the presence of gum disease, were linked to an increased risk of cognitive decline or dementia. Which is interesting considering a 2013 study found gum disease bacteria in the brains of Alzheimer’s disease patients — but this study in no way proved that gum disease causes Alzheimer’s disease. It just acknowledged an association.

However, researchers involved with the current review also noted that the findings based on the number of teeth or cavities are conflicting, and limited studies suggested that the dental conditions such as gingivitis are associated with cognitive decline. Similarly, the team didn’t regularly find that cognitive decline was associated with greater loss of teeth or number of decayed teeth. However, it is likely that "methodological limitations play a major role in explaining the inconsistent findings," they wrote.


"There is not enough evidence to date to conclude that a causal association exists between cognitive function and oral health. For future research, we recommend that investigators gather data from larger and more population representative samples, use standard cognitive assessments and oral health measures, and use more sophisticated data analyses," Dr. Wu said.

Saturday, August 11, 2018

Belly Fat May Cause Cognitive Impairment


Belly fat cognition

A team of scientists from 3 Irish universities – St. James's Hospital and Trinity College Dublin, both in Northern Ireland, and Nutrition Innovation Centre for Food and Health at Ulster University – found that having higher levels of belly fat in old age is associated with a decrease in cognitive function.

Prevalence of Alzheimer’s and other forms of dementia is growing with the rise in average age of population. Currently, an estimated 47 million people worldwide are affected by dementia. This number is expected to rise to 75 million by 2030.

Scientists are trying to understand the risk factors involved in dementia as it will help us with potential interventions to lower the risk of this condition developing as we age. One such risk factor is obesity.

Earlier studies have shown that overweight or obese adults do not perform as well on tests of memory and visuospatial ability compared to those who are a normal weight. However, researchers aren’t sure if this trend continues into older age.

While previous studieshave looked into this matter, the results produced were contradictory. Since each study involved different forms of cognitive test, it is difficult to conduct a meta-analysis with the pooled results.

For this new study, the researchers set out to answer this question more conclusively using a large-scale trial. [Read more High-fat diet damages brain, affecting learning and memory]

The scientists from the three universities used data from the Trinity Ulster Department of Agriculture aging cohort study, which is a cross-border collaborative research project gathering data from thousands of adults over the age of 60 in Northern Ireland and Ireland.

Each of the 5,186 participants was assessed using a number of cognitive tests.

The team found that a higher waist to hip ratio was linked with reduced cognitive function. This could be due to an increased secretion of inflammatory markers by belly fat, which in previous studies had been linked with a higher risk of cognitive impairment.

On the contrary, bodymass index (BMI) measurements did not show the same trend; in fact, higher BMI was found to protect cognitive function. Researchers believe this is because BMI is a crude measure of body fat and cannot differentiate between fat and fat-free mass (muscle); it only takes into account weight and height.  

How cognition is influenced by belly fat?

Researchers believe that belly fat's impact on cognition might be due to high secretion of inflammatory markers – particularly C-reactive protein. This chemical is produced when fat cells send out signals. Increased levels of this have previously been linked to cognitive decline.

It should also be noted that according to studies, levels of inflammatory markers in the blood increases in the lead-in to dementia, before symptoms appear. 

Hemoglobin A1C (HbA1C) is another molecule that seemed crucial. When during their analysis, the researchers controlled for levels of HbA1C, the significant effect of belly fat on cognition disappeared.

The prevalence of obesity and dementia are putting enormous burdens on the society. Studies like this are crucial because by reducing obesity we may be able to curtail the prevalence of dementia.
The findings are published in the British Journal of Nutrition.

Sunday, July 15, 2018

Exercise may protect against cognitive decline


Exercise may protect against cognitive decline

A new study conducted by researchers at the University of Miami in Florida, suggests exercise in older age may slow the rate of cognitive decline and knock off a decade of the brain.

Researchers found that adults over the age of 50 who engaged in light or no exercise showed a significantly faster decline in memory and cognitive skills, compared with those who engaged in moderate to intense exercise.

Similar research in the past suggested that any amount of exercise may reduce the risk of Alzheimer's disease by 50%.

Although, these types of studies are in abundance, researchers say it is important to understand how cognitive decline may be slowed by lifestyle factors, especially with an ageing population.

Dr.Clinton B. Wright, of the University of Miami in Florida notes:

"The number of people over the age of 65 in the United States is on the rise, meaning the public health burden of thinking and memory problems will likely grow.”

"Our study showed that for older people, getting regular exercise may be protective, helping them keep their cognitive abilities longer."

For the study, the researchers evaluated data of 876 adults aged 50 and older - an average age of 71 - free of memory and thinking problems that were part of the Northern Manhattan Study.
Participants were asked how often they had exercised in the previous 2 weeks and how long they had exercised for.


Almost 90% of the participants said they engaged in either light exercise or no exercise at all. The other 10% reported engaging in moderate to high-intensity exercise, such as running, aerobics or calisthenics.

Approximately seven years later, participants had to take part in memory and thinking tests and undergo brain imaging with Magnetic Resonance Imaging (MRI). The same cognitive tests were completed again five years later.

Participants who engaged in light or no exercise demonstrated a decline in memory and thinking skills compared with participants who did moderate or high-intensity exercise over a 5-year period. Researchers said the difference was comparable to 10 years of ageing.

According to the research team, this association remained after accounting for a number of potentially confounding factors, including alcohol consumption, smoking, body mass index (BMI) and blood pressure.

Dr. Wright said:

"Physical activity is an attractive option to reduce the burden of cognitive impairment in public health because it is low cost and doesn't interfere with medications.

Our results suggest that moderate to intense exercise may help older people delay aging of the brain, but more research from randomized clinical trials comparing exercise programs to more sedentary activity is needed to confirm these results."

The study was published online in the journal Neurology.