Sleep disorders

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  • Other sleep disorders
    • Narcolepsy
      • Black et al- narcolepsy affects 1 in 2000 people and is characterized by 4 major symptoms;
        • Cataplexy: the sudden loss of muscle tone whilst awake, can be brought on arousal - most common symptom
        • Hypnagogic hallucinations: dreamlike experiences when awake
        • Extreme daytime sleepiness: with short sleeps throughout the day
        • Sleep paralysis: inability to move during sleep
        • only 50% of sufferers show all symptoms
      • narcolepsy appears to reflect the invasion of REM into waking life because during REM the body loses tone (cataplexy), dreams occur (hallucinations) and when narcoleptics fall asleep they go straight into REM
      • Lin et al- the gene defect responsible for narcolepsy is on chromosome 12 and is responsible for regulating brain receptors for the neurochemical orexin- without these receptors orexin cannot function- this causes narcolepsy
        • Thannickal et al- orexin producing cells in the hypothalamus were reduced in narcoleptics
          • supported by Sakurai who found that injecting orexin into parts of the brain increases REM
            • Wickens- suggested that orexin is involved in the control of REM
      • Treatment and evidence for narcolepsy
        • narcolepsy usually develops in teen years
        • concordance rate of 30% in MZ twins- lots of room for enviromental influence
        • no drugs or treatment available yet so treatment usually involves stimulant drugs e.g. Ritalin which is used to treat ADHD usually- which act against daytime sleepiness
    • Nightmares and Night terrors
      • Nightmares are unpleasent dreams that occur in REM, have a story like structure and can be recalled
      • Night terrors occur when a persona wakes up terrified and crying but can't remember why
        • this is because they occur in N-REM so are not real dreams
          • occur mainly in children and are essentially harmless- most children grow out of them
    • Sleep walking
      • an event during sleep known as a parasomnia-
        • occurs in around 30% of 5-12 year olds and 1 in 5 regular children
          • it runs in families suggesting that there is a genetic element
      • takes place in the deeper stages of N-REM and walkers are usually found doing routine tasks
        • it is unknown why the brain activates the motor activity- sleepwalkers often have no memory of their actions
          • psychodynamic explanations attempt to explain it as the the desire to sleep where the individual slept as a child- reductionist
            • another explanation is that sleepwalking is an instinctive way to avoid unconscious activities in sleep
    • Sleep apnoea (SA)
      • reppeated eppisodes of breathing failiure during sleep lasting around 20-40 secconds - though they can last several minutes in rare cases
        • there must be at least 5 eppisodes a night to diagnose SA
        • can lead to headaches, insomnia, daytime sleepiness, and snoring/ dry mouth
      • Obstructive sleep apnoea (OSA)
        • caused by obstruction of the breathing passages
          • they can become blocked y enlarged tonsils or enlarged throat tissue
        • OSA is highly correlated with obesity and middle aged overweight sufferers are most common
          • weight loss and surgery are most popular treatments- or a breathing mask can be used
        • affects 4% of men and 2% of women   in the UK
      • Central sleep apnoea (CSA)
        • most symptoms are the same as OSA- however CSA is not associated with snoring and choking but with heart problems and cerebrovascular (blood supply to the brain problems) disease
          • often caused by a brain malfunction with the respiratory system
            • drugs to treat heart failure or cerebrovascular disease often work


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