Tag Archives: alzheimer's disease

More daytime sleepiness, more Alzheimer’s disease?

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Aging adults who report being very sleepy during the day were nearly three times more likely than those who didn’t to have brain deposits of beta amyloid, a protein that’s a hallmark for Alzheimer’s disease, years later.

The finding, published on Sept. 5 in the journal SLEEP, adds to a growing body of evidence that poor quality sleep could encourage this form of dementia to develop, suggesting that getting adequate nighttime sleep could be a way to help prevent Alzheimer’s disease.

“Factors like diet, exercise and cognitive activity have been widely recognized as important potential targets for Alzheimer’s disease prevention, but sleep hasn’t quite risen to that status–although that may well be changing,” says Adam Spira, associate professor at the Johns Hopkins Bloomberg School of Public Health.

“If disturbed sleep contributes to Alzheimer’s disease,” he said. “We may be able to treat patients with sleep issues to avoid these negative outcomes.”

The study used data from the Baltimore Longitudinal Study of Aging (BLSA) that was started way back in  1958 to follow the health of thousands of volunteers as they age. Volunteers filled a questionnaire between 1991 and 2000 that asked a simple yes/no question: “Do you often become drowsy or fall asleep during the daytime when you wish to be awake?” They were also asked, “Do you nap?” with response options of “daily,” “1-2 times/week,” “3-5 times/week,” and “rarely or never.”

A subgroup of BLSA volunteers also began receiving neuroimaging assessments in 1994. Starting in 2005, some of these participants received positron emission tomography (PET) scans using Pittsburgh compound B (PiB), a radioactive compound that can help identify beta-amyloid plaques in neuronal tissue, which are a hallmark of Alzheimer’s disease.

The researchers identified 123 volunteers who both answered the earlier questions and had a PET scan with PiB an average of nearly 16 years later and then analyzed it to see if there was a correlation between participants who reported daytime sleepiness and whether they scored positive for beta-amyloid deposition in the brain.

The results showed that those who reported daytime sleepiness were about three times more likely to have beta-amyloid deposition than those who didn’t report daytime fatigue. After adjusting for other health factors, the risk was still 2.75 times higher among them.

The unadjusted risk for amyloid-beta deposition was about twice as high in volunteers who reported napping, but this did not reach statistical significance.

It’s currently unclear why daytime sleepiness would be correlated with the deposition of beta-amyloid protein, Spira says. One possibility is that daytime sleepiness itself might somehow cause this protein to form in the brain.

Based on previous research, a more likely explanation is that disturbed sleep or insufficient sleep due to other factors, causes beta-amyloid plaques to form through a currently unknown mechanism, and that these sleep disturbances also cause excessive daytime sleepiness.

“However, we cannot rule out that amyloid plaques that were present at the time of sleep assessment caused the sleepiness,” he added.

This new study adds to growing evidence that poor sleep might actually contribute to Alzheimer’s disease development. Spira suggests that sleep quality could be a risk factor that’s modifiable by targeting disorders that affect sleep, such as obstructive sleep apnea and insomnia, as well as social- and individual-level factors, such as sleep loss due to work or binge-watching TV shows.

“There is no cure yet for Alzheimer’s disease, so we have to do our best to prevent it. Even if a cure is developed, prevention strategies should be emphasized,” Spira says.

Epileptic drugs linked to stroke in case of Alzheimer’s

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Antiepileptic drugs may increase the risk of stroke among persons with Alzheimer’s disease, said a new study from the University of Eastern Finland.

The risk remains the same whether the drugs are old or new antiepileptic drugs, said the study published in the Journal of the American Heart Association.

The study, conducted at the University of Eastern Finland and funded by the Academy of Finland, was based on the nationwide register-based MEDALZ cohort that includes all community-dwelling persons with clinically verified diagnosis of Alzheimer’s disease in Finland during 2005–2011 (70,718 people).

Data on antiepileptic drug use was compiled from the Finnish Prescription Register to assess the risk of stroke associated with antiepileptic drug use, and each antiepileptic drug user was matched to a non-user.

It was found that the risk of stroke was more during the first three months of antiepileptic drug use, and remains elevated after taking into account several chronic disorders, socio-economic position and use of concomitant medications.

According to another study from the same research group, persons with Alzheimer’s disease use antiepileptic drugs more often than persons without Alzheimer’s disease. The difference, which cannot be explained by epilepsy, is evident in antiepileptic drug use around the time when Alzheimer’s disease was diagnosed.

Up to 1% of population regularly requires chronic antiepileptic treatment to control epilepsy. Other indications for antiepileptic drug use include neuropathic pain and dementia-related behavioural symptoms in persons with Alzheimer’s disease.

The present findings show that persons with Alzheimer’s disease are particularly susceptible to adverse events, hence, the use of antiepileptic drugs for other indications than epilepsy should be carefully prescribed for this vulnerable population.

 

Forgetting Face Recognition? Check for Dementia, say Japanese Researchers

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A Japanese research group has proposed that failure to recognize or memorize human faces in the short term could be early stage of dementia. The elderly with mild cognitive impairment (MCI) suffer from weakened ability to recognize faces when compared to healthy elderly people. When trying to memorize, their gaze is also different, suggest Japanese researchers.

Alzheimer’s disease, the most common type of dementia, should be detected in its early stages to halt its progression into a more serious form of the disease. MCI, a preliminary stage of Alzheimer’s, is detected with weak cognitive functions, such as poor memory or inability to think though these traits do not affect daily life.

MRI scans of brain imaging show that areas for memory and visually processing human faces in people are structurally and functionally transformed during this stage.

Researchers from Kumamoto University in Japan conducted comparative experiments with normal elderly subjects and MCI patients (18 each) using a delayed-matching task with face and house stimuli in independent blocks.

In each block, they asked subjects to remember a single image and then, after a short delay, select a memorized image from a set new of images. The researchers also recorded subject gaze trends during the image memorization process.

Their experiments revealed that the memorization performance of MCI patients was lower for facial images than for house images. However they found no performance difference in normal subjects.

While memorizing, MCI patient’s gaze concentration on the eyes of an image decreased but the time spent looking at the mouth increased. They had reduced short-term memorization ability and a different gaze pattern for faces when compared to normal people, said researchers.

“Looking at the eyes is important for remembering the entirety of the face,” said Emeritus Professor Kaoru Sekiyama. “MCI patients probably have an abnormality in the cognitive processing of faces due to the deterioration of brain function. It is possible that the distributed gaze pattern is compensation for this decreased function.”

This research was published online in the journal Scientific Reports.

Noninvasive eye scan could detect key signs of Alzheimer’s years before patients show symptoms

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Cedars-Sinai neuroscience investigators have found that Alzheimer’s disease affects the retina — the back of the eye — similarly to the way it affects the brain. The study also revealed that an investigational, noninvasive eye scan could detect the key signs of Alzheimer’s disease years before patients experience symptoms.

Using a high-definition eye scan developed especially for the study, researchers detected the crucial warning signs of Alzheimer’s disease: amyloid-beta deposits, a buildup of toxic proteins. The findings represent a major advancement toward identifying people at high risk for the debilitating condition years sooner.

The study, published today in JCI Insight, comes amid a sharp rise in the number of people affected by the disease. Today, more than 5 million Americans have Alzheimer’s disease. That number is expected to triple by 2050, according to the Alzheimer’s Association.

“The findings suggest that the retina may serve as a reliable source for Alzheimer’s disease diagnosis,” said the study’s senior lead author, Maya Koronyo-Hamaoui, PhD, a principal investigator and associate professor in the departments of Neurosurgery and Biomedical Sciences at Cedars-Sinai. “One of the major advantages of analyzing the retina is the repeatability, which allows us to monitor patients and potentially the progression of their disease.”

Yosef Koronyo, MSc, a research associate in the Department of Neurosurgery and first author on the study, said another key finding from the new study was the discovery of amyloid plaques in previously overlooked peripheral regions of the retina. He noted that the plaque amount in the retina correlated with plaque amount in specific areas of the brain.

“Now we know exactly where to look to find the signs of Alzheimer’s disease as early as possible,” said Koronyo.

Keith L. Black, MD, chair of Cedars-Sinai’s Department of Neurosurgery and director of the Maxine Dunitz Neurosurgical Institute, who co-led the study, said the findings offer hope for early detection when intervention could be most effective.

“Our hope is that eventually the investigational eye scan will be used as a screening device to detect the disease early enough to intervene and change the course of the disorder with medications and lifestyle changes,” said Black.

For decades, the only way to officially diagnose the debilitating condition was to survey and analyze a patient’s brain after the patient died. In recent years, physicians have relied on positron emission tomography (PET) scans of the brains of living people to provide evidence of the disease but the technology is expensive and invasive, requiring the patient to be injected with radioactive tracers.

In an effort to find a more cost-effective and less invasive technique, the Cedars-Sinai research team collaborated with investigators at NeuroVision Imaging, Commonwealth Scientific and Industrial Research Organisation, University of Southern California, and UCLA to translate their noninvasive eye screening approach to humans.

The published results are based on a clinical trial conducted on 16 Alzheimer’s disease patients who drank a solution that includes curcumin, a natural component of the spice turmeric. The curcumin causes amyloid plaque in the retina to “light up” and be detected by the scan. The patients were then compared to a group of younger, cognitively normal individuals.

Vitamin B12 Deficiency Sensor Developed to Detect Dementia, Alzheimer Disease in Minutes

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In old-age, the frequent occurrence of B12 deficiency could lead to dementia and even Alzheimer’s disease as the body metabolism fails to absorb the vitamin from the diet, requiring an early medical intervention.

To help detect B12 deficieny early, Australia’s University of Adelaide researchers have developed a first of its kind optical sensor using a technique called Raman spectroscopy that can detect vitamin B12 in diluted human blood – a first step towards a low-cost, portable, broadscale vitamin B12 deficiency test.

The sensor, still at proof-of-concept stage, has wide-reaching potential applications. It enables doctors in tracking vitamin B12 levels in high-risk patients and provide an early intervention – to top up immediately vitamin B12 levels when low. Current tests are lengthy and costly too.

Scientists in the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), the Institute for Photonics and Advanced Sensing, and the Schools of Physical Sciences and Medicine, in their presentation today at an international biophotonics conference in Adelaide – the inaugural SPIE BioPhotonics Australasia conference — revealed the new sensor.

“Vitamin B12 deficiency has been shown to be a potential modifiable risk factor for dementia and Alzheimer’s disease and is associated with cognitive decline,” says Dr Georgios Tsiminis, Research Fellow at the University of Adelaide.

“Our sensor is an early first step towards a point-of-care solution for measuring and tracking B12 in healthy ageing adults. This would allow doctors to monitor B12 levels and intervene.”

"Currently our device could not aid in diagnosing vitamin B12 deficiency in a general practice setting… We believe this is a very promising first step towards achieving this goal," she said.

The optical sensor measures B12 in human blood in less than a minute and requires minimum preparation. This is the first demonstration of vitamin B12 being measured in human blood serum without the need for a full lab tests.

The sensor uses an optical measuring technique called Raman spectroscopy which produces a unique optical fingerprint of a target molecule, in this case vitamin B12.


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