Diagnostic Tests
Sleep studies
Diagnostic tests are essential for the assessment of many sleep disorders. They are broadly known as ‘sleep studies’. There are a variety of ‘sleep studies’.
- Home Sleep Apnoea Tests:
There are a variety of tests for diagnosing Sleep Apnoea. They are usually carried out in conjunction with a clinical assessment. Perhaps the best home test for diagnosing Sleep Apnoea is Cardio-respiratory Polygraphy. This test is also known by a number of other names including Polygraphy, Level 2 sleep study, Multichannel Sleep Study, Limited Polysomnography, Limited channel sleep study etc. A simpler test would be overnight Pulse Oximetry although this test is not good to exclude a diagnosis of sleep apnoea. Both these tests are carried out at the patients home.
- Full Polysomnography (PSG):
PSG is a comprehensive sleep study. During a PSG, we monitor sleep by monitoring electrical activity of the brain (‘brain waves’), eye movements and chin muscle tone. We also monitor breathing, blood oxygen level, pulse, electrical activity of the heart and limb movements. A full PSG is essential for diagnosis of conidiations such as Narcolepsy, REM Sleep behaviour Disorder, Periodic Limb Movement Disorder and other neurological sleep disorders. This is considered the ’gold standard’ test for diagnosing Sleep Apnoea.
Full PSG is usually carried out in a sleep laboratory. We are able to arrange full PSG in patients’ home.
- Multiple Sleep Latency Test (MSLT):
MSLT measures the propensity to sleep in the daytime. It is used mainly to diagnose narcolepsy but is also needed in other conditions causing excessive daytime sleepiness (EDS).
- Maintenance of Wakefulness Test (MWT)
This test measures the ability to keep awake under controlled conditions. This test is helpful when we need to objectively establish that one is able to keep awake and alert in the daytime.
- Actigraphy:
Actigraphy is used to monitor sleep over longer periods of time (usually two weeks.
Lung Function Test
Spirometry is the standard lung function test. It measures the Vital Capacity (VC), Forced Vital Capacity (FVC), and Forced Expiratory Volumes (FEV). This is probably the single most useful measure of lung function
We provide sleep studies in conjunction with a clinical consultation. Please contact us if you need further details.
1. Pulse oximetry: This is a standard test for diagnosing sleep apnoea. This is also known as a ‘Level 1’ sleep study. The pulse oximeter measures pulse rate and blood oxygen saturation. Pulse oximeters used for diagnosis of sleep apnoea are able to record these parameters over several hours. The data is processed by the software which generates a report which is interpreted by the technologist/physician to diagnose sleep apnoea.
2. Cardio-respiratory Polygraphy (‘polygraphy’ or Level 2 sleep study): In addition to pulse rate and oxygen saturation, we measure the respiratory airflow and chest/abdominal wall movements during a Cardio-respiratory Polygraphy. This test is better able to distinguish between obstructive and Central Sleep Apnoea. It also helps to diagnose Positional Obstructive Sleep Apnoea.
3. WatchPAT sleep study:
In addition to pulse rate and oxygen saturation, this test indirectly measures sleep by monitoring the peripheral blood vessel tone.