Sleep Disorders

Although we spend 30% of our time asleep, surprisingly little research has been done into this extraordinary phenomenon, and in the past sleep has been assumed to be a rather passive state. Following the first description of rapid eye movement (REM) sleep in 1957, further work on sleep staging using EEG and the recognition of cycling between REM and non-REM sleep, demonstrated that sleep is in fact a most active process.

1. Narcolepsy

This tends to run in families and symptom onset tends to occur in adolescence or in young adult life. There is a tetrad of characteristic features. Firstly, there is an irresistable urge to sleep which might, for example, occur during eating or in mid-conversation. Secondly, there is cataplexy, a transient loss of body tone, often only a nod of the head or a buckle at the knees, though occasionally a fall, usually triggered by strong emotion such as anger or often laughter. Thirdly, sleep paralysis is a terrifying feeling of being unable to move which usually occurs as you drop off to, or surface from, sleep. Lastly, there may be vivid visual hallucinations again occurring at sleep onset or on rousing. Treatment is often with a number of drugs directed at these different components of the tetrad.

2. Obstructive Sleep Apnoea (OSA)

This is another cause of excessive daytime sleepiness. It usually occurs in middle-aged overweight men who snore. If observant, their partners may notice that they stop breathing during sleep. Sufferers may complain of bad nightmares but they usually perceive their sleep quality to be fair. They frequently wake with headache and by day they are tired and nod off. Clues on examination include floppy redundant soft palate and uvula, a small tight-looking oropharynx and a short stocky neck (large collar size). Diagnosis is by overnight sleep study either in hospital or with the use of a domiciliary kit. Treatment is by weight reduction and continuous positive airways pressure (CPAP) or less commonly nowadays, by aggressive airway surgery.

3. Anxiety/Depression

Poor sleep quality in these conditions is very common and results in daytime sleepiness. The problem may be one of getting off to sleep or alternatively waking in the early hours with difficulty in getting back to sleep. Physical symptoms including pain, cough, urinary frequency and restless legs, as well as many drugs, including alcohol & caffeine can affect sleep in a similar way.

4. Parasomnias

These are, for the time being, a poorly described group of disorders in which sleep is disturbed by physical symptoms. They range from simple enuresis or bed-wetting to sleep/wake transition symptoms such as hypnic jerks (very common and benign) and arousal disorders – examples include sleep walking and talking. Some of the most interesting parasomnias are associated with REM sleep, occurring more usually in the second half of the night. Messages to muscle are turned off in REM sleep, so muscles are paralysed and limp – dreams & nightmares occur in this stage. Sometimes this system goes wrong and you wake up unable to move (sleep paralysis), in other cases muscles are reconnected in sleep so nightmares are acted out (REM sleep behaviour disorder) leading to unintended partner assault, falling out of bed & injury.