Written by Dr. Anitha Paderla, MBBS | 
Medically Reviewed by dr. reeja tharu / dr. sunil shroff, MBBS, MS, FRCS (UK), D. Urol (Lond) on Apr 19, 2013


a. Sleep latency: The amount of time it takes for a person to fall asleep

b. Sleep apnea: Periodic cessation of breathing during sleep causing arousals from sleep.

c. Circadian Rhythm Sleep Disorders: Sleep disorders that are caused due to disturbance in the normal 24 hour sleep wake cycle.

d. Periodic Limb Movement Disorder:Abnormal and repeated leg movements in sleep which causes considerable sleep disturbance.

e. Restless Legs Syndrome: A disorder characterized by aching or burning sensations in the lower limbs that occur in sleep and that may awaken the patient from sleep.

f. Narcolepsy: A disorder that manifests with repeated episodes of daytime sleepiness, accompanied by any or all of these conditions - sleep paralysis, cataplexy and hallucinations.

g. Menstruation: The normal cyclical discharge through the vagina of blood and mucosal tissues from the nonpregnant uterus.

h. Idiopathic: Unknown, a specific cause is not known.

i. Nor epinephrine: A neurotransmitter found in the sympathetic nervous system.

j. Dopamine: A neurotransmitter found in the extra pyramidal system of the brain, and important in regulating movement

k. Hypocretin: Hypocretin, a key neurotransmitter kindles the arousal centers in the brain to cause wakefulness. It also helps maintain wakefulness without falling asleep unexpectedly.

l. REM Sleep: It is so called because of the Rapid Eye Movements that occur during this phase of sleep

m. Sleep drunkenness: Movements or behaviors associated with sleep, sleep stages, or partial arousals (awakenings) from sleep that may impair sleep maintenance.

n. Hallucinations: Experiencing sensations in the absence of an appropriate stimulus, but which the individual regards as real.

n. Delusion: Experiencing abnormal sensations in the presence of an appropriate stimulus.

o. Schizophrenia: A severe emotional disorder characterized by delusion formation, hallucinations, emotional disharmony, and regressive behavior.

p. Theta Waves: A waveform recorded on an Electroencephalogram (EEG). It’s frequency range is normally between 5 and 8 cycles a second. It indicates a drowsy or idealing state of the mind. A person who has taken time off from a task and begins to daydream is often in a theta brainwave state.

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