Sleep is vital for overall health and well-being. However, many neurological disorders can negatively impact the quality and quantity of sleep. This article explores some common neurological conditions that disrupt normal sleep patterns.
Insomnia
Insomnia is one of the most common sleep disorders. It is characterized by persistent difficulties falling or staying asleep despite the opportunity to get adequate rest. Both onset insomnia (trouble falling asleep) and maintenance insomnia (frequent awakenings) can occur. Insomnia is linked to impairments in daytime functioning including fatigue, mood disturbances, and cognitive deficits. While transient insomnia is common, chronic insomnia may be caused by an underlying neurological issue like anxiety, depression, Alzheimer’s disease, or Parkinson’s disease.
Restless Legs Syndrome
Restless legs syndrome (RLS) is a sensorimotor disorder that causes uncomfortable sensations in the legs and an irresistible urge to move them. Symptoms are most prominent at rest, especially before sleep onset, frequently disrupting sleep quality. RLS may be a primary condition or secondary to iron deficiency, kidney failure, or pregnancy. The exact neurological mechanism is unclear but likely involves dopamine dysfunction.
Periodic Limb Movement Disorder
Periodic limb movement disorder (PLMD) is characterized by repetitive limb movements during sleep, usually in the legs. These brief muscle twitches called periodic limb movements often disrupt sleep continuity. Like RLS, PLMD may result from abnormal dopamine signaling. It can cause severe daytime sleepiness and impairment in quality of life. PLMD requires an overnight sleep study for diagnosis.
Narcolepsy
Narcolepsy affects the brain’s ability to regulate normal sleep-wake cycles. A dysfunctional hypocretin system results in extreme daytime sleepiness and sudden “sleep attacks”. Cataplexy, a sudden loss of muscle tone induced by strong emotions, is another classic symptom. Disrupted nocturnal sleep with vivid dreaming, sleep paralysis, and hallucinations upon awakening also occur. Currently, there is no cure, but stimulant medications can improve wakefulness.
Obstructive Sleep Apnea
Obstructive sleep apnea (OSA) arises from anatomical obstruction of the upper airway during sleep, causing pauses in breathing and loud snoring. These repeated respiratory disruptions lead to sleep fragmentation, daytime sleepiness, and an increased risk of cardiovascular disease. Neurological control of upper airway dilator muscles is impaired in OSA. Treatments include CPAP machines to splint the airway open, oral appliances, or surgery.
Alzheimer’s Disease
Up to 45% of Alzheimer’s disease patients develop sleep disturbances including insomnia, daytime sleepiness, and disrupted circadian rhythms. Brain regions that regulate sleep-wake cycles degenerate in Alzheimer’s. Daytime napping and nighttime wandering become more frequent as dementia progresses. Managing sleep issues can improve the quality of life for both patients and caregivers. A cognitive function test can screen for early cognitive decline if a patient has not yet been diagnosed.
Parkinson’s Disease
Parkinson’s disease attacks dopamine-producing neurons, resulting in motor symptoms like tremors and rigidity as well as non-motor symptoms such as sleep problems. Insomnia, daytime sleepiness, REM behavior disorder, and sleep apnea occur frequently. Sleep disturbances exacerbate motor symptoms and daytime fatigue. Addressing sleep disorders is an important part of Parkinson’s treatment.
Neurological disorders like Alzheimer’s, Parkinson’s, and narcolepsy can profoundly disrupt normal sleep cycles and circadian rhythms. Managing comorbid sleep disturbances through both pharmaceutical and behavioral interventions is critical for improving patients’ well-being. Adequate assessment and treatment of sleep disorders should be part of comprehensive care for those with neurological conditions. Cognitive assessments are a useful way of measuring the cognitive impacts of sleep disorders as well as detecting early signs of neurological conditions that could impact sleep.
