Sleep and Neurodegenerative Disorders

What is Sleep and Neurodegenerative Disorders?

Neurodegenerative disorders like Parkinson’s and Alzheimer’s are becoming more commonplace around the world, especially among older adults. Sleep issues are common in people with these conditions and often result from the disorders themselves, adding to the difficulties they face.

It’s important to understand that sleep issues and neurodegeneration influence each other. Neurodegenerative disorders can affect the parts of the brain that help us sleep. Meanwhile, problems with sleep can make neurodegeneration worse by disrupting the body’s protein cleanup process and increasing harmful oxidative stress.

Dealing with the main neurodegenerative disorder is critical, but tending to sleep disruptions in patients is equally challenging. People with these disorders often suffer from sleep disorders such as insomnia (difficulty falling or staying asleep), hypersomnia (excessive sleepiness), REM sleep behavior disorder (acting out dreams during Rapid Eye Movement sleep), obstructive sleep apnea (interrupted breathing during sleep), and restless legs syndrome (an irresistible urge to move the legs), among other issues.

Treating sleep issues in people with neurodegenerative conditions may improve their sleep-related symptoms and their overall quality of life. This is why it is essential to understand the causes, prevalence, symptoms, assessment, and treatment of sleep disorders in people with common neurodegenerative disorders like Parkinson’s and Alzheimer’s.

What Causes Sleep and Neurodegenerative Disorders?

People with diseases like Parkinson’s and Alzheimer’s often have trouble sleeping, which can affect their quality of life. It’s important to understand the different types of sleep problems related to these diseases to diagnose and treat them properly.

In people with Parkinson’s disease, common sleep disorders include insomnia, excessive sleepiness, and REM sleep behavior disorder (RBD), which causes people to physically act out their dreams, such as talking or moving around.

Insomnia, or trouble sleeping, is common in people with Parkinson’s disease. Various factors can contribute to this, such as:

* Physical symptoms like muscle stiffness and cramps can make sleeping more challenging.
* Needing to urinate a lot during the night (nocturia) can cause sleep interruptions.
* Levodopa/carbidopa, a common Parkinson’s medication, can potentially make insomnia worse.
* Depression, which can occur alongside Parkinson’s, may cause trouble sleeping.
* Other sleep issues like sleep apnea, restless legs syndrome, or sleep rhythm disorders can also coincide or worsen insomnia.

Both physical symptoms — such as shaking and stiffness — and non-physical symptoms, like frequent urination, can disrupt sleep in people with Parkinson’s. Current research is also looking into how the disease itself might contribute to insomnia, including possible damage to the brain’s sleep centers.

Excessive sleepiness during the day can also be a problem. Factors that might contribute to this include:

* Possible side effects of medications such as dopamine therapy.
* Loss of a particular type of brain cell may contribute to feeling sleepy a lot.
* Other sleep issues like sleep apnea, RBD, or sleep rhythm disorders can also make daytime sleepiness worse.
* Daytime sleepiness might also be connected to nerve cell loss in a specific part of the brain in people with Parkinson’s disease.

Sleep issues like sleep apnea – where breathing is interrupted during sleep – can often occur in people with Parkinson’s due to various reasons such as stiffness, trouble with breathing muscles, increased muscle tone in the throat, and other factors.

In Alzheimer’s disease, sleep problems are generally prevalent, particularly nighttime confusion known as sundowning. This condition is characterized by becoming more confused and irritable as the day goes on, leading to sleep disturbances. Factors contributing to this include:

* Damage to specific parts of the brain that control sleep can cause sleep disturbance.
* Changes to circadian rhythms (our internal body clock) can increase the risk of Alzheimer’s disease.
* Reduction in a hormone called melatonin, which helps regulate sleep-wake cycles, can lead to disrupted sleep rhythms resulting in daytime sleepiness and nighttime insomnia. This happens due to damage in a specific part of the brain, although, interestingly, the gland which produces melatonin remains unaffected by Alzheimer’s disease.
* Underlying mental health conditions like depression or anxiety can cause both daytime sleepiness and nighttime insomnia.
* Not getting enough light during the day or too much light at night before bed can impact sleep.

People with Alzheimer’s might have a higher chance of developing sleep apnea due to changes in the brain’s control of breathing. Sleep apnea can worsen cognitive decline in Alzheimer’s, but treatment with positive airway pressure therapy may help slow down this decline.

Risk Factors and Frequency for Sleep and Neurodegenerative Disorders

In 2016, 6.1 million people worldwide were diagnosed with Parkinson’s disease. As the population ages, this figure continues to increase. On average, there are 94 cases per 100,000 people each year, with the disease mostly affecting older individuals. The total number of people with Parkinson’s disease for every 100 people, adjusted to the European population standard, is 1.6. The number of cases tends to increase with age, with varying rates in different age groups.

• Almost all individuals with Parkinson’s disease will experience sleep issues at some point, with up to 98% affected.
• Common sleep-related problems include difficulty in falling asleep, excessive sleepiness, and rapid-eye-movement sleep behavior disorder (RBD).
• Restless leg syndrome (RLS) occurs in 15% to 20% of patients with Parkinson’s disease, though having it in early life doesn’t mean one will develop Parkinson’s disease later on.
• Severe RLS, however, can indicate the onset of Parkinson’s.
• RBD is found in about 46% of individuals with Parkinson’s.
• People with Parkinson’s disease often also have sleep-disordered breathing (SDB), but the reported frequency of overlap varies due to factors like differing criteria for defining respiratory events, varying degrees of disease severity, or different diagnostic methods used.
• An example is when standard sleep testing methods were used, 43% of a group of 49 people with Parkinson’s disease were found to have obstructive sleep apnea.

Around the world, it’s estimated that over 55 million people have dementia, with Alzheimer’s disease accounting for the majority of the cases. Sleep problems are common among those affected, with over half experiencing insomnia. In a particular study, it was found that more than 90% of those diagnosed with RBD, confirmed by sleep testing, went on to develop a neurodegenerative disease like Parkinson’s or Alzheimer’s within 14 years of their RBD diagnosis. The median time to diagnosis for these patients was 7.5 years.

Signs and Symptoms of Sleep and Neurodegenerative Disorders

Understanding and addressing sleep troubles in patients with degenerative brain diseases require careful patient history and physical examination. Through these, doctors can identify specific sleep problems impacting each patients’ overall health and life quality.

In Parkinson Disease, patient’s experiences may vary. Complaints may range from feeling sleepy during the day, loud snoring, trouble falling and staying asleep, issues with memory, mood shifts, and morning headaches. Some symptoms could result from the side effect of drugs used for managing Parkinson’s, hence it’s crucial to have a detailed record of all medications and non-prescription drugs in use. Many patients with Parkinson’s also often experience excessive sleepiness, sudden periods of overwhelming drowsiness while driving. Such tendencies are usually associated with Parkinson’s medication. Often, Parkinson’s patients are screened for other conditions that could affect sleep such as depression, sleep apnea, REM sleep behavior disorder, and restless leg syndrome.

• Daytime sleepiness
• Loud snoring
• Insomnia
• Mood changes
• Cognitive deficits
• Morning headaches

For patients living with Alzheimer’s Disease, there can also be a variety of sleep problems. Besides having memory and cognitive function loss, they may experience significant difficulty falling asleep, which could distress their families. Their circadian rhythms (sleep-wake cycle) often get interrupted, leading to irregular sleeping patterns. On top of that, other sleep conditions such as restless leg syndrome or sleep apnea should be checked. Due to disrupted sleep, restlessness and confusion during nighttime are often faced by these patients.

• Cognitive function decline
• Trouble falling and staying asleep
• Sleep cycle disruption
• Irritability and confusion at night

Testing for Sleep and Neurodegenerative Disorders

When we look into sleep disorders in patients with diseases that lead to the degeneration of the brain, or neurodegenerative diseases, the examination process is comprehensive. This means it involves a detailed medical assessment and specific tests. This rigorous evaluation is key to pinpointing specific sleep problems and tailoring effective treatment plans.

For Parkinson’s disease patients experiencing sleep disorders:

First is insomnia. To find potential causes of insomnia, we ask patients about any physical symptoms at night (like cramps, stiffness, or difficulty turning in bed), need to urinate often during the night, mood disorders, sleep apnea, or Restless Legs Syndrome. We also ask about recent changes in Parkinson’s medications. If the patient has trouble remembering, tools like sleep logs, diaries, and sleep trackers can help. The patient might also fill out questionnaires to help understand their sleep problems better, and specific tools may be used to evaluate the probability of Obstructive Sleep Apnea (OSA).

When we suspect that insomnia might be due to OSA, other sleep disorders, or particular types of sleep disorders related to abnormal behavior or movements during sleep (parasomnia), we can do a sleep study, which measures different aspects of sleep and can give us a lot of information about the patient’s sleep patterns.

Next is REM sleep behavior disorder, where patients act out vivid, often unpleasant dreams with sounds and sudden, often violent arm and leg movements. To confirm this, we ask the patient’s bed partner or caregiver about any instances of such behavior. Essential diagnostic tools include laboratory video and Polysomnography (a sleep study with extra muscle activity recordings).

Restless Legs Syndrome (RLS) is a disorder where there’s an urge to move the legs due to an uncomfortable sensation, often worse in the evening and at rest but relieved by movement. We need to distinguish RLS symptoms from nocturnal leg cramps, as the former should follow a daily variation and be relieved by movement.

Hypersomnia, or excessive sleepiness, requires evaluating other sleep disorders and whether the patient recently started dopamine therapy, a common treatment for Parkinson’s disease.

There can be challenges in diagnosing Sleep-Disordered Breathing due to the complications of Parkinson’s disease. To confirm this condition, we recommend sleep studies, but these might not be accessible for all patients. Home sleep apnea tests offer a simpler method but aren’t yet validated for patients with Parkinson’s disease.

When evaluating Alzheimer’s disease patients with sleep disorders:

It’s beneficial to ask about sleep disturbances during routine clinic visits. When insomnia is suspected, a detailed sleep schedule history is necessary, along with questioning about time spent outdoors, caffeine, alcohol, smoking, nighttime disturbances, and physical activity.

Some patients might have issues with their sleep-wake cycle, known as Circadian Rhythm Sleep Disorders. Patients might be asked about confusion and agitation at night. They’re likely to have extended time taken to fall asleep and wake up later in the day.

If a patient is excessively tired during the day, snores at night, or has complications associated with sleep apnea, they should be evaluated for Obstructive Sleep Apnea. We can use questionnaires and sleep studies for evaluation, or home sleep apnea tests in patients who frequently feel sleepy during the day, snore habitually, and have noticed episodes of interrupted breathing or gasping during sleep.

Treatment Options for Sleep and Neurodegenerative Disorders

Treating sleep problems in patients with brain diseases requires a mix of medication, behavioural therapies and lifestyle changes. The aim is to improve the patient’s quality of life and manage any related symptoms. These treatments are personalised to address the unique challenges that come with these conditions and sleep disorders.

For insomnia, identifying the underlying sleep disorder and the practice of good sleep hygiene are crucial. Cognitive behavioural therapy, which involves talking to a mental health professional to identify and change thought patterns, is recommended as the first course of action. Movement problems can interfere with sleep in patients with Parkinson’s disease, and these can be managed using drugs that replace dopamine, a chemical that sends signals in the brain. If these drugs cause insomnia, they can be reduced or given at different times.

For patients with Alzheimer’s disease, making changes to the environment they live in is usually the best first step. This includes keeping the environment quiet and dark at night and avoiding disruptions to sleep. Additionally, keeping a regular sleep cycle can also help. Physical activity and exposure to bright light in the morning can help maintain a consistent wake-up time. It’s also crucial to be careful with medications that can disrupt sleep, like antipsychotic drugs and stimulants.

Disruptions in the sleep-wake cycle are a significant cause of insomnia in older adults. Guiding them to maintain a steady sleep-wake schedule can help combat this issue. Bright light therapy in the evening can also help in resetting their body clock.

In cases of Restless Legs Syndrome, iron replacement is recommended if the patient has low levels of iron. Treatment includes dopamine agonists such as pramipexole and alpha-2-delta ligands such as gabapentin and pregabalin.

For hypersomnia, or excessive daytime sleepiness, counseling focusing on improving sleep hygiene can help. If individuals with Parkinson’s disease have hypersomnia, reducing the dose of certain Parkinson’s drugs may be the initial course of action.

In REM Sleep Behaviour Disorder, drugs that help you relax such as clonazepam and melatonin can help. Sleep apnea can be managed by controlling obesity, avoiding alcohol, and reducing the use of sedating medications.

Treatments for sleep-related issues in Parkinson’s disease can sometimes be complex due to factors associated with the disease such as motor disability and upper airway dysfunction. Some patients may stop their treatment due to factors such as weakness, increased awakenings, and inconvenience. Therefore, patient-specific care is greatly needed.

Excessive daytime sleepiness associated with Parkinson’s can be tough to treat and could be due to a variety of factors. Some studies have suggested that the use of a drug named modafinil can improve sleepiness without major adverse effects. However, the sleepiness assessed objectively did not reveal significant improvement with this medication.

What else can Sleep and Neurodegenerative Disorders be?

People with Parkinson’s disease may have sleep disorders, and these conditions could be mistaken for each other. The list of possible conditions includes:

• Insomnia
• Delayed sleep-wake disorder and restless legs syndrome, both of which are circadian rhythm disorders
• Sleep apnea and periodic limb movement disorder, which can cause difficulties maintaining sleep
• Advanced sleep-wake phase disorder and depression, which can cause early morning awakening
• Restless legs syndrome, muscle cramps, and nocturnal motor symptoms due to Parkinson’s disease medications wearing off
• Rapid Eye Movement (REM) sleep behavior disorder
• Non-REM parasomnias, parasomnia overlap disorder, nightmares, obstructive sleep apnea, periodic limb movement disorder, and sleep-related hypermotor epilepsy

People with Alzheimer’s disease may also have sleep disorders. The conditions to consider in this case include:

• Non-24-hour sleep-wake rhythm disorder, shift-work disorder, and jet lag disorder, all of which are circadian rhythm disorders
• Insomnia, which may be caused by a short sleep duration, chronic sleep insufficiency, circadian rhythm sleep-wake disorders, restless legs syndrome, obstructive sleep apnea, and psychiatric disorders like depression and anxiety
• Hypersomnia, or excessive sleepiness, caused by insufficient sleep, obstructive sleep apnea, central sleep apnea, and narcolepsy

Both Parkinson’s and Alzheimer’s patients can suffer from obstructive sleep apnea and excessive daytime sleepiness, which can be caused by:

• Insufficient sleep
• Narcolepsy
• Circadian rhythm disorder
• Restless legs syndrome
• Periodic limb movement disorder
• Neurodegenerative diseases
• Medications

What to expect with Sleep and Neurodegenerative Disorders

People with REM sleep behavior disorder (a condition in which people act out their dreams) often run a high risk of later developing Parkinson’s disease or other related disorders. Approximately, 33% chance in 5 years, 75.7% in 10 years, and 90.9% risk in 14 years. Therefore, these individuals need to have regular check-ups to watch out for early signs of these diseases, and if necessary, further tests may be conducted.

In people with Parkinson’s disease who also have REM sleep behavior disorder are found to be more prone to issues like falls, dementia, hallucinations, and autonomic dysfunction (problems with the body’s automatic functions like heartbeat and digestion). They also respond less to treatment and the condition deteriorates more rapidly, thereby increasing the burden of disease compared to those without REM sleep behavior disorder.

For healthy individuals, lack of sleep has been linked to a rise in beta-amyloid levels – a substance which can potentially cause Alzheimer’s disease over time. People with dementia often experience sleep disturbances, and these can exacerbate cognitive decline. Reduced REM sleep (the phase of sleep where we dream) has been associated with a higher dementia risk.

Sleep disorders seem to worsen as the disease progresses, and severe sleep issues in later stages of the disease can even forecast a higher risk of death. The life expectancy of an Alzheimer’s patient can vary greatly depending on the severity of their condition, but in many cases is approximately 4 to 6 years.

Possible Complications When Diagnosed with Sleep and Neurodegenerative Disorders

Sleep disorders can make life really hard for patients with brain diseases that get worse over time. It’s not an easy path to take, as getting treatment or not treating the condition presents its own issues. All of these can greatly affect a person’s health and quality of life.

If sleep disorders are left untreated, the following problems may arise:

• Obstructive sleep apnea can lead to dementia, brain degeneration, and heart issues such as high blood pressure, heart attack, and stroke.
• Insomnia can cause high blood pressure, diabetes, depression, obesity, heart attack, and stroke.
• REM sleep behavior disorder can cause injury to the person or their bed partner, and can also lead to conditions that affect the brain and nerves.
• Restless legs syndrome can cause insomnia, anxiety, and depression.
• Circadian rhythm disorder can cause agitation and confusion, notably in older patients with dementia, as well as cause problems in personal relationships.

On the other hand, in terms of treatment complications:

• Continuous positive airway pressure therapy, a treatment where a machine is used to help a person breathe more easily during sleep, can cause a runny nose, dry mouth, nosebleeds, and skin irritation.
• Melatonin, a hormone that helps control sleep cycles, can cause the central nervous system to slow down, hallucinations, and restlessness.
• Bright light therapy, a treatment that resets your sleep-wake cycle, can cause headaches, nausea, and excessive bodily movement.

Preventing Sleep and Neurodegenerative Disorders

If you have Alzheimer’s or Parkinson’s disease, it’s important to keep an eye out for any sleep disorders. Signs such as restless sleep, difficulty falling asleep, moving around in your sleep or moving your legs repetitively could mean you have a sleep-related disorder. If you notice these symptoms, you should get checked out by a healthcare provider.

Your healthcare provider can make an assessment based on your detailed history and by asking you specific questions about your sleep. Medical examinations such as a sleep study can help diagnose certain disorders, like sleep apnea, which is a condition that causes breathing to stop and start during sleep.

The most common way to treat sleep disorders is by taking simple steps like improving sleep habits and lifestyle alterations, depending on the type of sleep disorder. This could mean keeping a consistent sleep schedule, not drinking coffee, smoking, or alcohol in the evening, reducing exposure to light before going to sleep, and making sure your bed is used only for sleeping.

If you are diagnosed with sleep apnea, you might be asked to use a device like a breathing mask (CPAP) while you sleep at night. For some disorders related to the sleep cycle, treatments such as bright light therapy and physical activities may be recommended. In certain circumstances, you may be prescribed medications like melatonin.

If sleep disorders like sleep apnea aren’t treated, they can lead to serious health problems including high blood pressure, heart attacks, and other severe heart conditions. Promptly addressing sleep disorders may help delay the progress of dementia and other diseases that cause the brain and its functions to deteriorate over time.