EEG, Sleep and Circadian Rhythm Flashcards
Which part of the brain controls sleep?
Reticular formation in the brainstem
Which part of the brain is involved in the induction of sleep?
Suprachiasmatic nuclei (SCN) in the hypothalamus
Which hormone produces feelings of sleepiness?
Melatonin
Which hormone is required for wakefulness and where is it released from?
Orexon/hypocretin
Which part of the reticular formation is responsible for wakefulness?
Ascending Reticular Activating System (ARAS)
How are levels of consciousness assessed in an awake patient?
1) Assess behaviour, general alertness, speech content, reading, writing, calculating skills etc.
2) EEG
What are the four types of waves seen on an EEG?
Alpha, beta, theta and delta
What waves are most commonly seen on an EEG when a person is in a relaxed, awake state?
Alpha waves (high frequency, high amplitude)
What waves are most commonly seen on an EEG when a person is alert and awake?
Beta waves (very high frequency, low amplitude)
When are theta waves commonly seen on an EEG?
In children, during stress and frustration in adults and during sleep in adults and children (low frequency, varying altitude)
When are delta waves seen on a EEG?
Deep sleep ( low frequency, high altitude)
What is the 1st stage of the sleep cycle?
Slow wave, non-REM sleep, slow eye movement, light sleep, theta waves
What is the 2nd stage of the sleep cycle?
No eye movements, frequency slows and sleep spindles (bursts of rapid waves)
What is the 3rd stage of the sleep cycle?
Delta waves interspersed with short episodes of faster waves
What is the 4th stage of the sleep cycle?
Exclusively delta waves
What is the 5th stage of the sleep cycle?
REM sleep - dreams occur during this stage
Waves are very similar to those of someone who was awake
What happens to BP, respiration and metabolic rate during deep sleep?
BP decreases
Respiration decreases
Basal metabolic rate decreases
Can dreams occur during deep sleep?
They can but are rarely remembered
What happens to HR and resp. rate during REM sleep?
They become irregular
What happens when a person becomes sleep deprived?
Impairment of cognitive function, impairment of physical performance, sluggishness and irritablity
Why is sleep important?
Sleep supports: neuronal plasticity, leaning and memory, cognition, clearance f waste from the CNS, conservation of body energy and immune function
What is the definition of insomnia?
A chronic inability to obtain the necessary amount or quality of sleep to maintain adequate behaviour
What effect do barbiturates have on sleep?
Depress REM and delta sleep
When do night terrors occur?
In delta sleep
