Sleep problems linked to age-related cognitive problems

  • A very large Canadian study found that older adults with chronic insomnia performed significantly worse on cognitive tests.
  • A small study links older adults' increasing difficulties with consolidating memories to poorer synchronization of brainwaves during sleep.
  • A fruitful study shows that oxidative stress drives sleep, and that this is regulated by a specific molecule that monitors the degree of oxidative stress.

Chronic insomnia linked to memory problems

Data from 28,485 older Canadians (45+) found that those with chronic insomnia performed significantly worse on cognitive tests than those who had symptoms of insomnia without any noticable impact on their daytime functioning and those with normal sleep quality. The main type of memory affected was declarative memory (memory of concepts, events and facts).

Chronic insomnia is characterized by trouble falling asleep or staying asleep at least three nights a week for over three months with an impact on daytime functioning (mood, attention, and daytime concentration).

https://www.eurekalert.org/pub_releases/2019-05/cu-cia051519.php

Poor brainwave syncing behind older adults failure to consolidate memories

We know that memories are consolidated during sleep, and that for some reason this consolidation becomes more difficult with age. Now a new study shows why.

To consolidate memories (move them into long-term storage), low and speedy brain waves have to sync up at exactly the right moment during sleep. These brain rhythms synchronize perfectly in young adults, but in old age, it seems, slow waves during non-rapid eye movement (NREM) sleep are not so good at making timely contact with the speedy electrical bursts known as “spindles.”

These difficulties are thought to be due to atrophy of the gray matter in the medial frontal cortex.

The study compared the overnight memory of 20 healthy young adults to that of 32 healthy older adults (mostly in their 70s). Before going to sleep, participants learned and were then tested on 120 word sets. They were tested again in the morning. EEG results from their sleeping brains showed that in older people, the spindles consistently peaked early in the memory-consolidation cycle and missed syncing up with the slow waves.

http://www.futurity.org/memories-sleep-older-adults-1633432/

https://www.eurekalert.org/pub_releases/2017-12/uoc--obd121417.php

Oxidative stress governs sleep

A fruitfly study has shown how oxidative stress leads to sleep. Fruitflies (and, it is believed, humans) have sleep-control neurons that act like an on-off switch: if the neurons are electrically active, the fly is asleep; when they are silent, the fly is awake. The switch is triggered, it appears, by an electrical current that flows through two ion channels, and this, it now appears, is regulated by a small molecule called NADPH.

The state of NADPH reflects the degree of oxidative stress. Sleeplessness causes oxidative stress, driving the behavior of NADPH.

I'm wildly speculating here, but is it possible that increased sleep problems often found with age are linked to a growing inability of this molecule to sensitively monitor the degree of oxidative stress, perhaps due to high levels of oxidative stress??

https://www.eurekalert.org/pub_releases/2019-03/uoo-saa032119.php

Reference: 

[4475] Cross, N. E., Carrier J., Postuma R. B., Gosselin N., Kakinami L., Thompson C., et al.
(2019).  Association between insomnia disorder and cognitive function in middle-aged and older adults: a cross-sectional analysis of the Canadian Longitudinal Study on Aging.
Sleep. 42(zsz114), 

[4477] Helfrich, R. F., Mander B. A., Jagust W. J., Knight R. T., & Walker M. P.
(Submitted).  Old Brains Come Uncoupled in Sleep: Slow Wave-Spindle Synchrony, Brain Atrophy, and Forgetting: Neuron.

[4476] Kempf, A., Song S. M., Talbot C. B., & Miesenböck G.
(2019).  A potassium channel β-subunit couples mitochondrial electron transport to sleep.
Nature. 568(7751), 230 - 234.

Related News

Link among Alzheimer's disease, Down syndrome, atherosclerosis and diabetes

It’s been suggested before that Down syndrome and Alzheimer's are connected. Similarly, there has been evidence for connections between diabetes and Alzheimer’s, and cardiovascular disease and Alzheimer’s. Now new evidence shows that all of these share a common disease mechanism.
Hypertension linked to dementia in older women

Part of the Women's Health Initiative study looking at the effect of hormone therapy on thinking and memory in postmenopausal women, involving over 1400 women, has found those who had high blood pressure at the start of the study (eight years earlier) had significantly higher amounts of

Specific hippocampal atrophy early sign of MCI & Alzheimer's

A three-year study involving 169 people with mild cognitive impairment has found that those who later developed Alzheimer's disease showed 10-30% greater atrophy in two specific locations within the

Mental fluctuations may signal Alzheimer's disease

A study involving 511 older adults (average age 78) has found that 11.6% of those with very mild or mild Alzheimer’s (43% of the participants) had mental lapses, compared to only 2 of the 295 without Alzheimer’s. Those with mental lapses also tended to have more severe Alzheimer’s.
Training program improves eating skills of dementia patients

Loss of memory and problems with judgment in dementia patients can cause difficulties in relation to eating and nutrition; these problems in turn can lead to poor quality of life, pressure ulcers and infections.
Nutritional drink may help fight Alzheimer's

A European trial involving 225 patients with mild Alzheimer's has found that those who drank Souvenaid (a cocktail of uridine, choline and the omega-3 fatty acid DHA, plus B vitamins, phosopholipids and antioxidants) for 12 weeks were more likely to improve their performance in a delayed verbal

Subjective memory loss may increase risk for MCI & dementia

Subjective cognitive impairment (SCI), marked by situations such as when a person recognizes they can't remember a name like they used to or where they recently placed important objects the way they used to, is experienced by between one-quarter and one-half of the population over the age of 65.
Exercise helps prevent, improve MCI

A German study involving nearly 4000 older adults (55+) has found that physical activity significantly reduced the risk of developing mild cognitive impairment over a two-year period.
Connection between navigation, object location, & autobiographical memory

Rodent studies have demonstrated the existence of specialized neurons involved in spatial memory.
HIV infection prematurely ages the brain

Although HIV doesn't directly infect neurons, it appears that once it has crossed the blood-brain barrier, it affects supporting cells that can release immune factors that harm neurons.

Pages

more
Subscribe to Latest newsSubscribe to Latest newsSubscribe to Latest health newsSubscribe to Latest news