Sleep Disorders

Snoring is the sound produced by the structures in the mouth and throat vibrating whilst we are breathing during sleep. Snoring can cause sleep disturbance to the individual, but often causes social problems and sleep disturbance to others around as well. Snoring occurs when the airflow is slightly restricted causing turbulence.

If airflow restriction is increased, it can cause a condition called Upper Airways Resistance Syndrome.

Up to 40% of the population snore. Snoring becomes more common through aging due to the muscle tone reducing.

Snoring can also occur with Obstructive Sleep Apnoea.

Common risk factors for snoring include :

There are treatments which may be effective in reducing snoring such as myofunctional therapy exercises and nasal splints or mandibular advancement devices.

Sleep Apnoea is caused by the airway space in the mouth and throat reducing to the point at which there is no flow of air into the lungs. Each apnoea must last at least 10 seconds to be considered significant. The reduction of airflow to 50% of baseline is called a hypopnoea, this must also last at least 10 seconds and cause a drop-in blood oxygen levels.

Sleep apnoea may be categorised as :

Sleep apnoea only occurs during sleep, it develops slowly over time and affects sleep quality by causing micro arousals in sleep i.e. broken sleep. Sleep apnoea has many associations and consequences such as heart disease, strokes, diabetes and dementia. Sleep apnoea is associated with metabolic syndrome ( a combination of type 2 diabetes and hypertension with obesity) and closely associated with bruxism and atrial fibrillation. Most patients complain of poor quality sleep or sleepiness during the daytime long before the harmful effects of sleep apnoea occur.

Sleep apnoea may also be associated with an increase in blood pressure, due to the stimulation of the body during the night to stay in a light sleep/waking state. Obesity can cause sleep apnoea; this can be resolved with weight loss.

Restless Leg Syndrome is a condition which occurs more commonly in the over 50s.

Symptoms involve unpleasant sensations in the legs when sitting at rest, which may improve upon walking and movement. Some may experience the sensation of insects crawling up the legs and find this symptom worsens in the evening. Restless leg syndrome can disrupt sleep due to repetitive leg twitches during the night. Periodic limb movements are often seen in patients incidentally during an overnight sleep study and are far more common in patients with restless leg syndrome.
Restless leg syndrome often requires treatment such as medications and or sleep hygiene. If iron levels are low, correcting these can help.

A large proportion of the population experience repetitive limb movements during the night and often these are of no consequence. If you have daytime sleepiness associated with periodic limb movements at night these may be causing awakenings and disrupting sleep.

Unusual behaviours during the night, for example sleep walking and sleep talking, are termed Parasomnias. These are not harmful and rarely need treatment, they are purely self-limiting. Very rarely other sleep disorders may be noticed such as; groaning at night (Catethrenia), acting out dreams (REM Behaviour Disorder) or recurrent night terrors and nightmares. Parasomnias require specialist sleep studies to diagnose these.

Narcolepsy is a rare condition which occurs when the central process for wakefulness is damaged. Profound sleepiness occurs during the daytime despite adequate sleep at night. There may be disturbed sleep at night as well as sleep attacks during the daytime.
Narcolepsy may be an autoimmune condition which may take more than 20 years to diagnose from the original episode.

Narcolepsy has also been known to occur following infections such as influenza, encephalitis and glandular fever. Very rarely narcolepsy can occur after a significant head injury.

Narcolepsy sufferers find daytime naps are often needed in order to function.
A very rare form of Narcolepsy with Cataplexy is known to occur if the person finds that they collapse or suffer weakness when experiencing emotional states such as laughing and crying.

Insomnia occurs if patients cannot fall asleep or stay asleep, currently incidence of insomnia in the general population is up to 40%. Chronic insomnia may be diagnosed if sleep is disturbed three night a week or more, for three months or longer.

Treatments for insomnia include cognitive behavioural therapy and medications.

Circadian Rhythm Disorders are disruptions in a person’s sleep pattern which is maintained by our internal body clock. Our bodies contain genes colloquially referred to as Clock Genes. Clock Genes control most hormonal and behavioural body rhythms, such as when we feel the most sleepy or most alert. In fact, most of the life on earth, such as plants and animals, are controlled by clock genes.

These genes cycle over 24 hours. Timing is closely aligned to the earth’s day and night cycle by a master clock called the Suprachiasmatic nucleus.

The master clock may work out of synchronisation in cases such as when a person travels across more than three time zones. This master clock often alters in puberty, resulting in teenagers sleeping later in the night as well as awakening later.

Disorders of the master clock often result in extreme variation in timings of sleep (i.e. the sleep pattern). Delayed sleep phase syndrome is a Circadian Rhythm Disorder which results in later bedtimes and, consequently, later waking times.

Advanced Sleep Phase Syndrome occurs when the bedtime and rise time are much earlier than normal. Free running sleep rhythm occurs due to loss of the entrainment and therefore resetting of the master clock. The sleep onset at bedtime is advanced or occurs later each day.

People who experience this may eventually reverse their sleep timing so that they are awake all night and asleep all day. These Circadian Rhythm Disorders are common and respond well to treatment.