A diagnostic sleep study, technically known as a ‘polysomnogram’ or ‘PSG’, is a special form of medical test done when a sleep disorder is suspected and the doctor wants to know what is happening while you sleep.
Sleep disorders range from relatively mild conditions, such as simple snoring, through to very serious conditions such as obstructive sleep apnoea, narcolepsy, restless legs syndrome and sleep walking. A sleep study requires that you be fitted with a diagnostic recorder which will monitor your brain activity (including the levels of sleep you cycle through), your cardiac or heart activity, your breathing patterns and any stoppages, your blood oxygen levels, your limb movements, your sleeping position… and much more.
The study is usually done in a hospital-based sleep laboratory environment, where a sleep scientist will be present to monitor you throughout the night. More recently, there has been a dramatic growth in the use of portable or ‘in home’ diagnostic recorders. These portable recorders mean the patient can sleep in the comfort and privacy of their own home, which usually means the whole experience is much less expensive, less daunting and ultimately more indicative of what a normal night’s sleep looks like for the particular patient.
The following morning, the recorded data is downloaded and studied by a sleep scientist and a specialist sleep physician. The recorded data is enough for these experts to be able to diagnose the nature and severity of any condition and usually enough to base a prescription for treatment on.
In the vast majority of cases, the results of the sleep study come as a complete surprise to the individual who is undergoing it. That is because, obviously, the person is asleep while the various events occur and so they have no conscious recollection of the event.
For instance, a person with severe obstructive sleep apnoea (which is where the soft tissue of the upper airway collapses and obstructs the airway, literally stopping the patient from breathing) will stop breathing for at least 10 seconds (but more likely 20 to 30 seconds at a time) for a minimum of 30 times each hour they’re asleep.
As the body begins to starve of oxygen, the sympathetic nervous system momentarily wakes the sufferer with what is known as a ‘micro arousal’. This micro arousal is only just enough to get the body breathing again, but the patient is not roused enough to be consciously aware of awakening.
As a result, people with sleep disorders will often wonder why they are getting, say, 8 hours sleep per night but still waking up feeling tired. The reality is that they’ve woken at least 30 times per hour for each of those 8 hours — so they’ve effectively had around 240 short naps, rather than true, restorative, restful sleep.
Once confronted by the data showing what happens while they’re asleep, most patients understand the urgent need to seek treatment.
If you think you have a sleep disorder, or if your doctor recommends you get one, go ahead as soon as possible. The study is completely non-invasive and, apart from the various wires and electrodes which are attached to the body, relatively comfortable. But the results of the study could uncover a range of conditions which impact negatively on your health, wellbeing and relationships. A range of professional, effective treatments are then available to resolve any issues which are discovered.