Neurodegenerative Diseases and Sleep

What is Neurodegenerative Disease?

Neurodegenerative disease is an umbrella term for various conditions that affect neurons in the brain. In neurodegenerative diseases, neurons in the brain and elsewhere become damaged and die, causing both ataxias (problems with movement and motor function) and dementias (problems with mental function).

Neurons are nerve cells in the brain and peripheral nervous system. They are key to the essential functions of our bodies and minds, and once damaged, they’re irreplaceable. They don’t self-produce and can’t be rehabilitated. This means that neurodegenerative diseases are incurable and usually progressive, meaning that they worsen over time.

Neurodegenerative diseases are relatively common, affecting millions of people globally. The two most common types of neurodegenerative diseases, for example, are Alzheimer’s disease and Parkinson’s disease. Alzheimer’s diseases represents 60-70% of all neurodegenerative diseases. Other common neurodegenerative diseases include motor neuron disease, Huntington’s disease, spinal muscular atrophy (SMA), prion disease, spinocerebellar ataxia (SCA), and amyotrophic lateral sclerosis (ALS).

In the U.S. alone, at least 500,000 Americans are experiencing Parkinson’s disease and around a million Americans are living with Alzheimer’s disease at any given time. The risk for developing a neurodegenerative disease greatly increases as we age.

Additionally, these diseases are associated with a range of possible sleep disturbances and conditions. The type of sleep condition varies according to the neurodegenerative disease and its severity.

Different Types of Neurodegenerative Diseases

There are a number of different kinds of neurodegenerative diseases, all of which affect the body and mind differently. These are the most widely-known neurodegenerative diseases, along with information about their symptoms, possible causes, and associated sleep conditions.

Alzheimer's Disease (AD) and other Dementias

Alzheimer’s disease is a brain disease, primarily characterized by memory loss that disrupts everyday life. Other symptoms include difficulties in reasoning and judgment, challenges in completing daily tasks, problems with frequently losing items, and issues with writing, speaking, and spatial reasoning. Alzheimer’s patients also often experience significant changes in mood and behavior.

There is no known single cause of Alzheimer’s disease. Age is the single most important risk factor, but lifestyle and environmental factors, such as a history of head injuries and cardiovascular problems, can also contribute. Family history also plays a role, as do genetics.

Associated Sleep Disorders:

  • Insomnia
  • Sleep Apnea
  • Circadian Rhythm Disorder
  • Restless Legs Syndrome

Parkinson’s Disease (PD)

Parkinson’s disease is caused by damage to the brain’s dopamine-producing nerve cells. The disease is progressive, with symptoms showing up slowly over time. The progression of Parkinson’s disease usually begins with mild tremors and alterations in posture and walking before causing severe slowness and rigidity of movement.

Like Alzheimer’s, Parkinson’s disease has no single known cause. Instead, it is believed to be caused by a combination of environmental, genetic, and lifestyle factors. There are some genetic markers for the disease, but the implications of how they interact are not yet conclusive. Some researchers believe that toxins like pesticides might play a role in the development of Parkinson’s disease as well.

Associated Sleep Disorders:

  • Insomnia
  • Sleep Apnea
  • REM Sleep Behavior Disorder
  • Hypersomnia

Huntington's Disease (HD)

Huntington’s disease is a progressive brain disease that causes uncontrollable body movements, as well as problems with reasoning, cognition, and judgment. It can also lead to mental health and mood-related symptoms, like anxiety, depression, and anger. The characteristic jerking movements associated with Huntington’s disease are called “chorea.”

Unlike Alzheimer’s disease and Parkinson’s disease, Huntington’s disease has a single known genetic origin: a defective gene located on chromosome 4 that codes the protein known as huntingtin. Symptoms usually appear in middle age, though they can appear much earlier or later.

Associated Sleep Disorders:

  • Insomnia
  • Circadian Rhythm Disorder
  • REM Sleep Behavior Disorder

Motor Neuron Diseases (MND)

Motor neuron diseases (MNDs) is an umbrella term that refers to a group of neurodegenerative diseases that damage and kill the motor neurons, which control the body’s voluntary movements. Motor neuron disease are progressive and incurable, and they can affect muscle strength and key behaviors like walking, speaking, breathing, and swallowing. Some motor neuron diseases are hereditary, but others develop due to inflammation or exposure to toxins or viruses.

The most common motor neuron diseases include amyotrophic lateral sclerosis (ALS), which affects the facial muscles as well as the legs and arms. Primary lateral sclerosis and progressive muscular atrophy are two other common MNDs that affect different parts of the body. Progressive bulbar palsy, another motor neuron disease, primarily affects the ability to chew, swallow, and speak.

Associated Sleep Disorders:

  • Insomnia
  • Sleep Apnea

Prion Disease

Prion diseases refer to a group of neurodegenerative diseases characterized by brain damage due to abnormal proteins in the brain. A prion is a protein that can cause healthy proteins in the brain to become damaged, leading to changes in memory, personality, behavior, cognitive function, and movement.

Prion diseases are relatively rare and are often caused by “mad cow disease” or exposure to contaminated meat. There are also “familial” prion diseases, which are caused by inherited gene mutations.

The most common type of prion disease is Creutzfeldt-Jakob disease (CJD), which can be sporadic (randomly occurring), familial (inherited), or acquired (due to “mad cow disease”).

Associated Sleep Disorders:

  • Insomnia
  • Hypersomnia

Spinal Muscular Atrophy (SMA)

Spinal muscular atrophy (SMA) is characterized by damage to and loss of motor neurons in the spinal cord that control voluntary movements. It leads to muscle atrophy, or wasting, and weakness, both of which worsen as the patient ages. SMA is classified by types 0 through 4, depending on the severity of symptoms.

Symptoms of spinal muscular atrophy may show up in childhood, adulthood, late adulthood, or even before birth. The disease is caused by mutations in the SMN1 gene that controls the body’s essential movements, while the severity of symptoms is determined by the number of copies of the SMN2 gene the patient has.

Associated Sleep Disorders:

  • Insomnia
  • Sleep apnea

Spinocerebellar Ataxia (SCA)

Spinocerebellar ataxia (SCA) is a neurodegenerative disease that primarily results in loss of coordination, balance, and typical walking ability. SCA may also affect speech, causing it to slur. SCA is caused by damage to the cerebellum, the part of the brain that modulates movement and gait. The many different kinds of SCA are classified by types SCA1 through SCA40.

There are a range of genetic mutations that are known to cause SCA. Meanwhile, acute cerebellar ataxia (ACA), a related neurodegenerative disease caused by damage to the cerebellum, can be precipitated by exposure to certain toxins or viruses, bacterial infections, head trauma, or severe vitamin deficiencies.

Associated Sleep Disorders:

  • Insomnia
  • Hypersomnia
  • Circadian Rhythm Disorder
  • Restless Legs Syndrome
  • Sleep Apnea
  • REM Sleep Behavior Disorder

Why do Neurodegenerative Diseases make it Harder to Sleep?

There are a few primary reasons that people with neurodegenerative diseases are likelier to experience sleep disorders. Neurodegenerative diseases often interfere with the neurological processes that regulate sleep and allow for healthy sleep-wake cycles.

These are the sleep disorders most often connected with neurodegenerative diseases:

Sleep Disorder Description Linked to these Neurodegenerative Diseases Why are they connected?
Sleep Disorder

Insomnia

Description

Insomnia is one of the most common sleep disorders, affecting about a fifth of Americans. Insomnia is defined by difficulty staying or falling asleep at least three nights a week, whether for less than three months (short-term insomnia) or three months or more (chronic insomnia).

Commonly associated with these Neurodegenerative Diseases

All of them

Why are they connected?

Difficulty falling asleep is a problem for many patients with Alzheimer’s disease and other neurodegenerative diseases. Research indicates this is due to a combination of factors, including changes to the parts of the brain that regulate sleep, side effects of medications, and anxiety or pain due to symptoms of the disease.

Sleep Disorder

Hyperinsomnia

Description

People with hypersomnia disorders usually sleep more than 9 hours over a 24-hour period. They experience persistent daytime sleepiness that’s not related to or explained by circadian rhythm disruptions or nighttime sleep disturbances.

Commonly associated with these Neurodegenerative Diseases

Parkinson’s Disease
Prion Disease
Spinocerebellar Ataxia

Why are they connected?

As with insomnia, hypersomnia can often go along with neurodegenerative diseases due to damage in the parts of the brain that aid in healthy sleep cycles. Hypersomnia is also sometimes caused by the effects of prescribed medications or psychiatric conditions, as well as other sleep disorders like RLS. Some ND medications may cause daytime sleepiness.

Sleep Disorder

Sleep Apnea

Description

Sleep apnea affects the ability to breathe normally during sleep. People with sleep apnea stop and start breathing repeatedly throughout the night due to problems with the muscles that control the body’s breathing mechanisms.

Commonly associated with these Neurodegenerative Diseases

Alzheimer’s Disease
Parkinson’s Disease
Motor Neuron Diseases
Spinal Muscular Atrophy
Spinocerebellar Ataxia

Why are they connected?

Neurodegenerative diseases can cause obstructive sleep apnea due to deterioration in the muscles that control breathing. Sleep Apnea can exacerbate the effects of neurodegenerative diseases by contributing to neuron damage through hypoxia, or a lack of oxygen in the bodily tissues.

Sleep Disorder

Restless Legs Syndrome

Description

Restless legs syndrome, or RLS, is a sleep disorder related to movement. In RLS, people feel “pins and needles” sensations and  intense urges to move their limbs when they’re trying to rest. RLS often causes sleep disturbances and fatigue.

Commonly associated with these Neurodegenerative Diseases

Alzheimer’s Disease
Spinocerebellar Ataxia

Why are they connected?

Restless legs syndrome is sometimes caused by deficiencies and dysfunction in the neurotransmitters that release dopamine, leading some clinicians to believe that it’s more common in patients with Parkinson’s disease. Parkinson’s disease is also marked by dysfunction in the release of dopamine.

Sleep Disorder

Circadian Rhythm Disorders

Description

Circadian rhythm disorders is an umbrella term that refers to disorders that disrupt the body’s natural sleep-wake cycle and negatively affect sleep timing. Examples can include jet lag and shift work disorder as well as delayed sleep phase disorder.

Commonly associated with these Neurodegenerative Diseases

Alzheimer’s Disease
Huntington’s Disease
Spinocerebellar Ataxia

Why are they connected?

The parts of the brain that regulate and modulate the normal, healthy sleep-wake cycle are often damaged by neurodegenerative diseases. Circadian rhythm disorders can sometimes also serve as an early warning of neurodegenerative diseases. As sleep loss accumulates, these effects can worsen over time.

Sleep Disorder

Rapid Eye Movement Sleep Behavior Disorder

Description

Rapid eye movement (REM) sleep behavior disorder is a parasomnia, or a disorder characterized by undesirable behavior during sleep, that causes uninhibited motor activities like walking, punching, running, hitting, or kicking during sleep. It can also cause talking or yelling during sleep.

Commonly associated with these Neurodegenerative Diseases

Parkinson’s Disease
Huntington’s Disease
Spinocerebellar Ataxia

Why are they connected?

REM sleep behavior disorder can be an early sign of Parkinson’s disease or other neurodegenerative diseases. In some cases, patients may develop REM disorder decades before the onset of Parkinson’s or other dementia. Clinicians recommend monitoring patients who exhibit signs of REM sleep behavior disorder for symptoms of Parkinson’s and other neurodegenerative diseases.

Sleep Disorders as an Early Sign of Neurodegenerative Diseases

There is significant evidence to suggest that sleep disorders can predict and even cause neurodegenerative diseases.

Rapid eye movement behavior disorder is a fairly reliable predictor of developing neurodegenerative diseases such as Parkinson’s. In fact, one study suggests over 80% of men with REM disorder will go on to develop Parkinson’s disease. Research indicates that REM disorder is linked to clusters of abnormal proteins in the brain that interfere with typical sleep patterns. The same clusters of proteins may contain clues as to why patients eventually develop neurodegenerative diseases.

Other neurodegenerative diseases, such as Alzheimer’s, have also been linked to sleep disorders in young adulthood and middle age. One possible reason is that, during sleep, our bodies undergo essential “cleaning processes” that sweep out wastes and unnecessary proteins from between the neurons in our brain. If sleep is disturbed, those processes are as well, possibly contributing to the later development of neurological problems.

Some clinicians now believe that sleep disorders are not just predictors of neurodegenerative diseases, but that poor quality sleep may actually contribute to the onset and exacerbation of these diseases. This means that ensuring high-quality sleep and practicing good sleep hygiene can be one tool to help prevent developing certain dementias later in life.

Current and Developing Treatments for Neurodegenerative Diseases

The best way to improve sleep problems associated with neurodegenerative diseases is to treat the underlying diseases as well as possible, under the advice of a qualified medical professional. There are a number of treatments that are currently used to manage and treat the symptoms of various dementias and ataxias associated with neuron damage and death. Although there are currently no cures, the following treatments are common:

Treating Symptoms of Neurodegenerative Diseases

Dopaminergic treatments for PD and movement disorders
Dopaminergic treatments have been shown to help manage symptoms in people with Parkinson’s and other movement disorders. “Cognitive apathy,” which may manifest as needing assistance to start mental activities and speech, appears to be related to decreased levels of dopamine, and dopaminergic treatment helps to curb this symptom.

Cholinesterase inhibitors for cognitive disorders
Cholinesterase inhibitors show some benefit as a pharmaceutical approach to treating the symptoms of Alzheimer’s disease. The effects of the drugs vary for different people. But there has been improvement shown in the ability to think clearly, memorize things, and function on a daily basis. These medications can also help with behavioral and psychological symptoms.

Antipsychotic drugs for behavioral and psychological symptoms of dementia
Drug trials have shown that some antipsychotic drugs (also known as “neuroleptics” or “major tranquilizers”) can reduce or eliminate the intensity of certain behavioral and psychological symptoms of dementia. There’s a small but significant beneficial effect on aggression and, to a lesser extent, psychosis, when these drugs are taken for a period of 6–12 weeks.

Analgesic drugs for pain
Drugs designed specifically for pain relief are called analgesics and have been found to provide relief for almost anyone with arthritis or related conditions. Neurodegenerative diseases often cause pain, and pain contributes to sleep loss. Several types of analgesics are available: Acetaminophen is available without a prescription, while opioids (also called narcotics) are only available with prescriptions. Some products combine acetaminophen with opioids for added relief.

Deep brain stimulation to stop tremor and refractory movement disorders
Deep brain stimulation is the current state-of-the-art treatment for the most common movement disorders, such as Parkinson’s disease. In deep brain stimulation, small electrodes are surgically placed within the brain to stop tremors and other symptoms associated with movement disorders.

Medicines for Slowing the Development of Neurodegenerative Diseases

Riluzole for ALS, cerebellar ataxia and Huntington’s disease
Riluzole is used to slow the progress of amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease), cerebellar ataxia, and Huntington’s disease. While not a cure, the drug may improve breathing, delaying the need for a tracheostomy or breathing tube. It is a prescription pill taken every 12 hours.

NSAIDs (non-steroidal anti-inflammatory drugs) for Alzheimer’s disease
NSAIDs (non-steroidal anti-inflammatory drugs) have shown promise in the treatment of Parkinson’s disease. The role of retaining information in PD has become more recognized recently, and anti-inflammatory drugs such as aspirin and ibuprofen have been shown to protect the neurons in the brain.

Caffeine A2A receptor antagonists for the neuroprotection of PD
Studies have shown that caffeine may reduce the incidence of Parkinson’s disease, particularly in men. Caffeine A2A receptor antagonists act upon the same receptors affecting dopamine function and signaling. More recent research suggests that they may not only improve symptomatic function in Parkinson’s disease but also may be neuroprotective.

Strategies for Sleeping with Neurodegenerative Diseases

In addition to treatments that specifically target the symptoms of neurodegenerative diseases, others address sleep problems themselves. These are a few key ways that you can get better rest with neurodegenerative diseases.

Practice Excellent Sleep Hygiene

First and foremost, the key to getting good sleep—especially with a condition such as a neurodegenerative disease—is practicing good sleep hygiene. Practicing good sleep hygiene is about creating rituals around your nightly sleep. You can start by going to bed at the same time every night and establishing a goal for how much sleep you need (for most adults, at least seven hours).

Creating a healthy sleep environment is also important to maintaining sleep health. Keep your bedroom dark, cool, and quiet. It’s also best to stop using electronics about an hour before bed, as the lights from smartphones and tablets can disrupt circadian rhythms. Try to avoid doing anything in your bed besides sleep and sex, so that your bed isn’t also a work environment or a place to lounge during the day.

Daytime habits are also important aspects of sleep hygiene. Exercising, getting sunshine, maintaining a healthy diet, limiting use of substances like alcohol and caffeine, and managing anxiety during the day can help you get a better night’s rest when you want to get some shuteye.

If people with a certain neurodegenerative disease have trouble creating these rituals for themselves, caregivers or loved ones can help remind them of their established routines in order to improve sleep hygiene.

CPAP/BiPAP Therapy

One of the most common sleep disorders associated with neurodegenerative diseases is sleep apnea. The muscle atrophy associated with some NDs can affect the muscles involved in breathing, thus leading to respiratory problems during sleep. Sleep apnea can also exacerbate the symptoms of neurodegenerative diseases, as the lack of oxygen can speed up neurological damage.

CPAP and BiPAP therapy are forms of positive air pressure therapy, in which airflow is pressurized and provided for people who have trouble breathing. CPAP machines provide continuous airflow using hoses, humidifiers, and face masks, while BiPAP machines deliver airflow based on the person’s own breathing patterns.

CPAP is best for people with obstructive sleep apnea, while BiPAP is best for people with central sleep apnea. Both BiPAP and CPAP machines are prescribed by physicians. Here’s our guides to the best CPAP machines and BiPAP machines on the market, from lightweight and portable to the most technically advanced.

Light Therapy

Another common sleep disorder experienced by some people with NDs is circadian rhythm disorder, in which our bodies’ natural sleep-wake cycles are disrupted and sleep timing is thrown off, leading to chronic fatigue and poor sleep quality in some cases.

Light exposure plays a major role in our bodies’ ability to adhere to a healthy circadian rhythm. In particular, natural light allows us to feel sleepy at night, get better quality sleep, and wake up rested and energized in the morning. Exposure to natural light also affects our vitamin D levels and our bodies’ production of important hormones like serotonin and melatonin that contribute to our sleep health. Light therapy is one way to improve the quality of sleep-wake cycles, improve sleep timing, and limit sleep disturbances.

Light therapy boxes are widely available at major retail outlets. Light therapy boxes emit high concentrations of artificial light that can serve as an alternative to natural light. People who use light therapy boxes effectively (usually about 20-60 minutes per day, just after waking up each morning) can help to reset circadian rhythms and improve their sleep-wake cycles over time.

Conclusion

Neurodegenerative diseases (NDs) affect essential functions in the brain and central nervous system due to the damage and death of neurons.

The most common neurodegenerative diseases are Alzheimer’s disease and Parkinson’s disease, but there are a range of others. Most neurodegenerative diseases affect movement or cognitive function, and many affect both.

Neurodegenerative diseases are often associated with, and may in some cases even be caused by, sleep disorders. Insomnia, hypersomnia, sleep apnea, restless legs syndrome, circadian rhythm disorders, and rapid eye movement behavior disorder are all linked to various NDs.

Neurodegenerative diseases are progressive and incurable, but there are medical treatments–including both prescription medications and clinical therapies–that can help to curb and manage symptoms.

To sleep better with neurodegenerative diseases, patients have a range of options. Depending on their symptoms and health conditions, they can practice good sleep hygiene habits or pursue light therapy or CPAP therapy.

Although there is no known cure for neurodegenerative diseases, with the right clinical care and lifestyle choices, sleep health can improve for people with NDs over time.

Additional Tuck Resources

For further information about how different conditions can impact sleep, check out the following Tuck resources: