Sleep-Wake Disorders: Most Prevalent Condition Revealed

Sleep-wake disorders are conditions that affect your ability to get the rest your body needs and maintain wakefulness. There are over 80 different types of sleep disorders, with insomnia being the most common. Sleep-wake disorders often co-occur with medical conditions or other mental health conditions such as depression, anxiety, or cognitive disorders. Sleep-wake disorders can be caused by a variety of factors, including internal factors such as a person's body clock being different from the light-dark cycle, or external factors such as shift work or jet lag. Sleep-wake disorders can have several symptoms, including difficulty falling asleep, trouble staying asleep, snoring, and feeling sleepy during the day.

Insomnia

Sleep-wake disorders, or sleep disorders, involve problems with the quality, timing, and amount of sleep, which result in daytime distress and impaired functioning. The most common sleep-wake disorder is insomnia, with about one-third of adults reporting insomnia symptoms and 4-22% meeting the criteria for insomnia disorder.

The prevalence of insomnia is estimated to be between 10% and 30% of the population, with some studies reporting rates as high as 50-60%. It is more common in older adults, females, and people with medical and mental ill health. Insomnia is associated with a wide range of impaired daytime functions across emotional, social, and physical domains, including higher rates of work absenteeism, diminished job performance, decreased quality of life, and increased healthcare utilisation. It is also linked to a higher risk of psychiatric disorders, with approximately 40% of adults with insomnia also meeting the criteria for a diagnosable psychiatric disorder, most notably depression.

The evaluation of insomnia typically involves a comprehensive assessment that includes a patient history, a physical exam, a sleep diary, and clinical testing such as a sleep study or polysomnography. Various self-answerable questionnaires are also available to aid in diagnosis, such as the Insomnia Severity Index, which is the most widely accepted clinical assessment tool for insomnia.

Parasomnias

REM parasomnias, on the other hand, typically affect adults and are associated with underlying neurological or degenerative brain conditions. REM sleep behavior disorder (RSBD) is characterized by acting out, vocalizing, or making aggressive movements in response to a violent dream. This disorder is more prevalent in adults and individuals with neurodegenerative diseases like Parkinson's disease, Lewy body dementia, or multiple system atrophy.

Sleep-related movement disorders

Sleep-wake disorders are characterised by problems with the quality, timing, and amount of sleep, which result in daytime distress and impaired functioning. Insomnia is the most common sleep-wake disorder, with about one-third of adults reporting insomnia symptoms and 4-22% meeting the diagnostic criteria for insomnia disorder.

Periodic Limb Movement Disorder (PLMD)

PLMD involves repetitive movements of the arms, legs, or feet during sleep. A person with PLMD may twitch or kick for 5 to 90 seconds at a time, at least 15 times per hour. These movements may cause the person to wake up, leading to sleep disturbances. People diagnosed with PLMD do not have conscious urges to move their limbs and do not experience the discomfort that is associated with Restless Leg Syndrome (RLS). PLMD is often diagnosed in polysomnograms and has been found to be prevalent in 31% of diabetic patients.

Sleep-Related Leg Cramps

Sleep-related leg cramps are sudden and involuntary muscle contractions that can last from a few seconds to several minutes. These cramps can make it difficult to fall asleep or cause a person to wake up in the middle of the night. Nocturnal leg cramps are common, with up to 60% of adults experiencing this symptom. They may be caused by muscle fatigue, nerve issues, underlying medical conditions, certain medications, or common daytime activities.

Bruxism

Bruxism is the medical term for jaw clenching and teeth grinding during sleep. The force exerted during teeth grinding can lead to tooth wear, pain in the teeth or jaw, and headaches over time. Bruxism is common in children, affecting between 6% to almost 50% of youngsters.

Restless Leg Syndrome (RLS)

RLS is characterised by an urge to move the legs, often accompanied by uncomfortable sensations in the legs. It occurs when a person is awake or on the verge of sleep. More than 80% of people with RLS also experience periodic limb movements during sleep.

Sleep apnea

The prevalence of sleep apnea has been increasing over the years, and this trend is particularly notable in the United States. Data from the American Journal of Epidemiology reveals that the rates of obstructive sleep apnea have surged significantly over the past two decades. This rise is attributed mainly to the obesity epidemic, as obesity is a significant risk factor for sleep apnea. Additionally, the increasing average weight of U.S. adults has been identified as a contributing factor to the growing prevalence of sleep apnea.

The National Healthy Sleep Awareness Project estimates that at least 25 million adults in the U.S. suffer from obstructive sleep apnea. This number highlights the impact of the disorder on public health and safety, as sleep apnea is associated with various health risks. These include an increased risk of high blood pressure, heart disease, Type 2 diabetes, stroke, and depression. The condition can also lead to cognitive impairments, mood disturbances, and issues with daytime alertness.

The diagnosis of sleep apnea typically involves a sleep study or polysomnography, which can be conducted in a sleep clinic or at home. During this study, sensors monitor an individual's heart rate, breathing, blood oxygen levels, and brain waves while they sleep. Based on the symptoms and the apnea-hypopnea index (AHI), which measures breathing cessation or hindrance during sleep, sleep apnea can be classified as mild, moderate, or severe. Treatment options for sleep apnea include continuous positive airway pressure (CPAP) therapy, positional therapy, and, in some cases, multiple types of treatment for severe sleep apnea.

Narcolepsy

Sleep-wake disorders, or sleep disorders, involve problems with the quality, timing, and amount of sleep, which result in daytime distress and impairment in functioning. While insomnia is the most common sleep-wake disorder, this answer will focus on narcolepsy, a sleep disorder that affects the brain's ability to control sleep and wakefulness.

Symptoms

People with narcolepsy often experience excessive daytime sleepiness (EDS), which can feel like a "sleep attack" where an overwhelming feeling of sleepiness comes on quickly. The severity of sleepiness varies among individuals, but it does not improve even after getting enough sleep at night. Other symptoms include cataplexy, which leads to sudden episodes of muscle weakness triggered by strong emotions, as well as hallucinations while falling asleep or upon waking up.

Diagnosis

To diagnose narcolepsy, a doctor will perform a clinical exam and take a detailed medical history, including a sleep journal noting sleep times and symptoms over one to two weeks. Two specialized tests are typically required to establish a diagnosis: a polysomnogram (PSG) or sleep study, and a multiple sleep latency test (MSLT). The PSG records brain activity, muscle movements, breathing, and eye movements during sleep, while the MSLT measures how quickly a person falls asleep and whether they enter REM sleep.

Treatment

Frequently asked questions