Sleep and its (medical) significance

 

Snoring and sleep apnoea 

Snoring is a noise phenomena that usually happen while inhaling asleep. Not every kind of snoring can be labeled as pathological. Reason for snoring is a vibrating in the upper areas of the human respiratory system that is caused by the stream of air in the inhalation phase. Especially in case of limited nasal breathing the stream of air will cause a snoring noise at the limp (or enlarged) soft palate. The transition to a pathological diagnosis, often called “dangerous snoring”, is caused by a constriction of the respiratory tract in the pharyngeal area. Although the thorax is moving, too little air can stream through the pharyngeal area.

 

A constriction of the air stream to less than 25% of the baseline by a disfiguration of the upper air ways in sleep is called “obstructive sleep apnoea”. Contrary to breathing-stops caused by diseases of the nervous system, respiratory efforts of the respiratory muscles are detectable.

The restriction of the respiratory tract, most often in the throat area, causes a lack of oxygen although the respiratory musculature is active and working. The result is a decreased level of oxygen (O2-saturation) in the blood. To prevent an asphyxiation, the “body awakens” and the throat muscle tone is stabilized. Those so called “arousals” are used to refuel with oxygen and always have an interrupting effect on sleep. This is also the case, even if the sleeping person is just pushed to a lighter sleep stage by the arousals and does not reach the full stage of wakefulness. Especially in this case the nocturnal interruption of sleep is “unconsciously” and cannot be remembered the following day. With obstructive sleep apnoea this process can be repeated throughout the whole night and destroy the natural restful architecture of sleep. The pathology is dependent on duration and frequency of the breathing times and the extent of the oxygen dosage.

 

Enabling factors for the obstructive sleep apnoea are an existing snoring, a reduces muscle tone in the throat (e.g. after alcohol consumption or under the influence of medicine) and a highly negative inhalation pressure (vacuum), which can be explained by a variance of the upper respiratory tract: e.g. curvature of the nasal septum, enlargement of the nasal concha or the palatine tonsils, retraction of the lower jaw and so on.

 

Obstructive sleep apnoea and sleep-related respiratory dysfunctions

Following nocturnal symptoms could refer to obstructive sleep apnoea:

restless sleep, sleep disturbances, daytime sleepiness, non-recuperative sleep, wakeup phase with a feeling of breathlessness, nocturnal palpitations or sweating, vertigo, increased urination.

This may result in the following symptoms:

early morning weariness or headaches, early morning dryness in the mouth- throat-area or sore throat, daytime sleepiness, emphasized sleepiness after lunch, difficulties to stay awake in monotonous situations, reduced efficiency, loss of libido or impotence, depressive mood.

 

Diagnosis of a sleep apnoea

Diagnosis in our office starts with an examination of the respiratory tract. This is done by an endoscopy to evaluate the anatomical conditions and mucous membranes, followed by a measurement of the nasal respiratory flow (rhinometry) and a pulmonary function. If necessary, an allergic disposition is done by a Prick-test and RAST (proof of specific IgE antibodies).

The main instrument to detect sleep apnoea is the polysomnogrpahy (PSG). The PSG collects a huge amount of parameters: sleep stages, body position, respiratory flow via mouth and nose, oxygen saturation (pulse oximetry), electrocardiogram, acoustic registration of snoring, respiratory act of the thorax and chest, as well as detectors for leg-movement while sleeping.

The available systems to record this parameters are very small and easy to handle for the patient. This measurements could be done home, as well as as stationary. The advantage of the “homely” measurement is in maintaining the usual sleep atmosphere. The measurement is more “representative” and not influenced by the unknown environment of the clinic. The use of the PSEdevice ist very easy and the patient can attache the sensors comfortably at home before going to sleep. Usually, the measurements are done on two following nights. This increases the informative value of the results.

The pathological evaluation of sleep relates to parameters like the ability to fall asleep, nocturnal sleep ability, the qualitative composition of nocturnal sleep including the cyclical sleep stages, as well as the respiratory physiology (oxygen supply) and maybe appearing arousals.

 

Therapy

As reasons for obstructive sleep apnoea are multifactorial, it is important that the chosen therapies are multilayered as well.
One of the first settings of the course, regarding the therapeutical options, is to make a diagnostic differentiation between the “more or less harmless” snoring and the sleep apnoea syndromes with nocturnal decrease of oxygen.

 

 

Stages of sleep

There are four stages of sleep that have to be separated from waking state. They can be classified by measurement of brain waves (EEG), the eye activity (EOG) und muscle activity (EMG). Sleeping stage N1 describes the transition from waking state and sleep, a kind of dozing. Sleeping stage N2 describes the stable sleep and sleeping stage N3 deep sleep. Sleeping stage R, the REM sleep (“rapid eye movement”) is often labeled as dream sleep or paradox sleep, what is not entirely correct. In this stage dreams are most intensive. Test persons awakened in this stage of sleep are most capable of recalling contents of their dreams. Furthermore, the wake up-threshold is highest in this stage, which is paradox, since EEG activity is extremely high and comparable to stage N1 or even wakefulness. In REM stage, it is most difficult to wake test persons up. The proportion of REM sleep is about 20-25% of the whole sleep.

In the course of an undisturbed sleep one goes cyclically through the various sleep stages from N1- N3 to REM sleep. REM sleep then closes the cycle of about 100 minutes sleep. In the course of a night the deep sleep stages become shorter and the REM sleep longer.

 

The sleeping time of newborns is about 14-16 hours, distributed to 4-5 sleeping phases. Newbornes spend about 8 hours in REM sleep, what is half of their sleep. This high proportion of REM sleep, which will decrease to about1,5 hours over the course of a lifetime, indicates that REM sleep plays an important role in the process of building neural networks. Usually, schoolchildren do not need day sleep phases anymore. A night sleep phase of 9-11 hours with a REM sleep of less than 35% is enough.

 

Sleep Disorders

The „International Classification of Sleep Disorders“ (ICSD) distinguishes six main groups of sleep disorders:

Insomnias (sleeplessness)

Sleep-related respiratory dysfunction (e.g. sleep apnoea)

Hypersomnias with central nervous reason (pathological sleep compulsion by the central nervous system like narcolepsy)

Disorder of the circadian rhythm (like jet lag)

Parasomnias

Sleep-related movement disorder (e.g. teeth grinding bruxism)

 

 

 

Children with sleep apnoea

 

“Snoring and sleep apnoea” with children is often ignored or neglected by their parents. The university clinic in Stanford (USA) states in a study that about 10% of the children under the age of 10 are snoring. And about 20% of these suffer from the so called obstructive sleep apnoea syndrome.

 

Sleep apnoea is here the very same as with adults: a sign for a distorted respiratory function and a hint for a possible undersupply of oxygen. Snoring can be a symptom for sleep apnoea. It is an indication that the kids' respiratory tract is partly misplaced.

 

There are various reasons for a sleep apnoea syndrome. Enlarged adenoids or enlarged tonsils are some of the main reasons for sleep apnoea with children. There are a couple of effective therapies for sleep apnoea with children.

 

Sleep apnoea with children is a serious condition that can prevent a normal (restful) night sleep, disturb growth and decrease quality of life. Sleep apnoea can lead to a daytime sleepiness that is
often confused with attention-deficit hyperactivity disorder (ADHD).

 

Watch your child during night sleep and pay attention to unrest, mouth breathing, snoring or breathing times.

 

Visit us, if you already must answer one of the following questions with “yes”:

 

       •  Is your child snoring?

       •  Do you register breathing times with you child?

       •  Do you register a lot of mouth breathing with your child?

       •  Does your child sleep through or are there sleep interruptions?

       •  Does your child suffer from bed-wetting?

       •  Is your child confused or irritated during the day?

       •  Are there concentration difficulties with your child?

       •  Does your child frequently suffer from headaches, especially in the morning?

 

As ENT-medicals with long-term experience with sleep medicine we can answer if you child is endangered by sleep apnoea and if so, we can also show you therapeutical options to deal with it.