Knowra Sleep disorder Sleep disorder A condition that disrupts sleep timing, duration, quality, or associated behaviors. Sleep disorders can impair daytime functioning and may arise from medical, psychological, behavioral, or environmental causes.
Sleep : A recurring biological state marked by reduced responsiveness, altered brain activity, and characteristic changes in bodily function. Normal sleep provides the baseline against which a disorder is identified.
Sleep architecture : The structure and sequence of sleep stages across a sleep period. Disorders can alter stage timing and continuity, not just total sleep duration.
Polysomnography : An overnight test that records brain activity, breathing, oxygen levels, heart rhythm, and movement during sleep. It helps identify sleep apnea, unusual sleep events, and other physiological disruptions.
Sleep deprivation : A state caused by obtaining less sleep than the body needs. Insufficient opportunity for sleep can mimic a disorder without constituting one itself.
Circadian rhythm : An approximately 24-hour biological cycle that coordinates bodily processes with day and night. Misaligned internal timing can produce disorders even when sleep itself is otherwise normal.
Homeostatic sleep pressure : The rising biological drive to sleep that accumulates during wakefulness and dissipates during sleep. Abnormal regulation can make sleep onset or sustained wakefulness difficult.
Multiple Sleep Latency Test : A daytime test measuring how quickly a person falls asleep across repeated nap opportunities. It supports evaluation of excessive sleepiness and narcolepsy.
Delayed sleep-wake phase disorder : A circadian rhythm disorder in which sleep and waking occur substantially later than desired or required. Its late schedule can resemble insomnia when a person tries to sleep at conventional times.
Insomnia : Persistent difficulty falling asleep, staying asleep, or obtaining restorative sleep despite adequate opportunity. It is a common disorder centered on difficulty initiating or maintaining sleep.
Melatonin : A hormone produced mainly at night that helps coordinate circadian timing. Its timing can be disrupted in circadian sleep disorders and influenced by treatment.
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