Sleep Flashcards
What is sleep?
Sleep is a reversible states of perceptual disengagement from and unresponsiveness to the environment.
Why do we sleep?
Importance of sleep isn’t fully undersold however various theories for the need to sleep include:
• metabolic - sleep is required to restore the energy resources of the body
• immune defence related - studies have shown that adequate sleep helps to fight infection
• brain plasticity related theories - evidence suggests that sleep enhances memory and learning while extended waking impairs cognitive performance
What are circadian rhythms?
A timing mechanism of clock that controls periods of activity and inactivity. It is also involved in influencing hormone release, body temperature and other important bodily functions. Circadian rhythms are controlled by the suprachiasmatic nucleus.
What controls the sleep wake cycle?
Daylight appears to have the most controlling influence on the daily sleep/wake cycle. As daylight decreases, the visual system sends signals to the SCN which in turn signals the pineal gland to produce melatonin.
What are the consequences of sleep deprivation?
- daytime drowsiness
- micro sleeps
- sleep seizures
- mood swings
- stress and anxiety
- lethargy
- reduced productivity
- reduced concentration
- reduced short term memory
- reduced creativity
What are the stages of sleep?
Sleep consists of non-rapid eye movement sleep (non-REM) and rapid eye movement sleep (REM).
Non-REM has 3 stages.
EEG, EOG and EMG are needed to identify sleep stages.
What is stage one sleep?
This is sleep onset and is between sleep and wakefulness. EEG shows mixed frequency/low amplitude vertex sharp waves, slow rolling eye movements, muscle gone starts to drop but muscles are still active.
What is stage two sleep?
K complexes and sleep spindles start to appear on the EEG and eye movement reduces. The EMG is less active than stage one and stage two accounts for 50% of total sleep time.
What is stage three sleep?
The EEG shows high voltage, slow activity known as delta waves. Eye movement is absent and EMG is low. This accounts for 15-20% of total sleep time.
What is REM sleep?
Paradoxical sleep - patient is unrousable but brain activity is as if the patient is awake. Muscles are paralysed and rapid eye movement and dreaming occurs.
What are the categories of sleep disorders?
- insomnia
- sleep disordered breathing
- hypersomnias not related to SDB
- circadian rhythm disorders
- parasomnias
- sleep related movement disorder
- isolated symptoms and unresolved issues/normal variants
What is insomnia?
Symptoms of insomnia include repeated difficulty with sleep intimation, duration, consolidation of quality that occurs despite adequate time and opportunity for sleep.
Give some examples of insomnias.
- idiopathic insomnia
- adjustment sleep disorder
- insomnia due to mental disorder
- inadequate sleep hygiene
- behavioural insomnia in children
- insomnia due to a medical condition
- insomnia due to drug or substance abuse
- non-organic insomnia
- organic insomnia
What are the diagnostic criteria for insomnia?
At least one of the following day time impairments related to night time sleep difficulty: • fatigue • attention, concentration or memory impairment • poor school performance • mood disturbances or irritability • daytime sleepiness • motivation reduction • errors at work or whilst driving • tension headaches • concerns or worries about sleep
What are hypersomnias?
The inability to stay alert and awake during a major waking episode.
