Trouble Sleeping Can Lead to Cognitive Impairment

For people experiencing insomnia, sleep deprivation, OSA or sleep disordered breathing, cognitive impairment is common. The brain is supposed to recharge and reset overnight.  Getting inadequate sleep lessens the chance of that recharge happening.  Multiple studies have linked poor sleep with longer-term cognitive decline, dementia, and Alzheimer’s.  Better sleep may reduce the likelihood of age-related cognitive decline and prompt sharper thinking.

Older adults with dementia typically exhibit significant sleep disturbances, including fragmented sleep, altered circadian activity patterns and elevated risk of SDB.  Findings such as these were traditionally thought to represent consequences Alzheimer’s disease (AD), however researchers have begun to examine whether sleep disturbances actually contribute to the risk of AD.  Cognitive decline is a common problem in aging populations and is a major health concern that creates daily challenges in activities of personal life and family functioning.   It is extremely important to identify any potential predictors of cognitive decline as soon as they are noticed, to develop preventative measures.

We all know how important sleep is for the brain.  It promotes and enhances function. This includes both REM and NREM sleep.  Sleep has multiple cycles/stages.  During each stage of sleep, levels of brain activity change. Getting high-quality sleep (not just quantity) supports concentration, memory, problem-solving, creativity, emotional processing, and judgment.

REM sleep is more concentrated than NREM sleep, and more so during the second half of the night. Each part of this process produces different chemicals in the brain, which become activated or deactivated to promote rest and recovery.

Scientists have hypothesized that REM sleep plays an essential role in the acquisition of learned material. It has been suggested that REM sleep is involved in declarative memory processes if the information is complex and emotionally charged, but probably not if the information is simple and emotionally neutral.  It has also been noted that slow-wave-sleep (SWS) plays a significant role in memory.  Slow-wave-sleep is a deep restorative sleep.

Short-term implications of poor sleep on the brain can be the result of simply pulling an all-nighter, while those with chronic sleep problems may see their day-to-day tasks affected. Over the long-term, poor sleep may put someone at a higher risk of cognitive decline and dementia.  Long-term effects can decrease motor skills, speech ability, place keeping and the ability to carry out instructions.

Most people are familiar with the daytime effects from a bad night’s sleep, such as drowsiness and fatigue.  In response, they may “nod off” for a few seconds sporadically, also known as microsleep. When this happens there is a slowing down of thinking and reaction times, similar to when people become intoxicated. 

Poor sleep impairs thinking by changing how emotional information is processed.  How do we interpret events?  Do we remember how to do daily tasks?  Things that are classified as procedural memory, like riding a bicycle, can often become forgotten.  When learning something new, analyzing a problem, or making a decision, insufficient sleep can get in the way of this ability.  As a result, mood is affected.  In many cases, this disrupted emotional response impairs judgment.  People experiencing this are more likely to make risky choices and to focus on a potential reward rather than the downside. It’s like instant gratification.  This can limit the ability to learn from these mistakes since the normal method of processing and consolidating emotional memory is compromised.

Impaired sleep increases the risks of infection and even the common cold.  Migraine sufferers are more likely to have morning headaches when they don’t sleep.  Not only the physical symptoms become apparent but the symptoms of mental health conditions like anxiety and depression can be worsened.  Keep in mind that not everyone is affected in the same way, and there could be a genetic component that plays a part.  

Typically, adults are better at overcoming these effects than younger people.  Teens are considered to be high-risk for effects of poor sleep in terms of thinking, decision-making, and academic performance, due mostly to the ongoing brain development occurring during a younger age.  Some studies have also found that women are more adept at coping with the effects of sleep deprivation than men, but more research needs to be done on this topic.  It is not clear if this is related to biological factors, social and cultural influences, or a combination of both.

Being chronically tired to the point of fatigue or exhaustion means that we are less likely to perform well.  Neurons do not fire optimally, muscles are not rested, and the body’s organ systems are not synchronized.  Lapses in focus from sleep deprivation can even result in accidents or injury.

Some people use sleep medication to achieve appropriate levels of sleep.  These medications and doses need to be monitored to prevent side effects.   There are many different types of sleep aids, some classified as antihistamines, some benzodiazepines, some antidepressants and then some over-the-counter options.  It is best to check with your PCP to determine the best medication, if any, that is tailored to your specific needs. 

Anyone who feels that they are experiencing cognitive impairment or excessive daytime sleepiness should talk with their doctor, who can help identify or rule out any other conditions, including sleep disorders, that may be causing these symptoms.

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