MWT (maintaining wakefulness test)

What is it?

MWT, or the maintenance of wakefulness test, is a procedure for examining the ability to stay awake. The sleep doctor may refer you to this procedure, if the ability to stay awake is to be studied.



The objective of the MWT is to objectively measure the patient’s ability to stay awake. Used for assessing the treatment outcome of sleep apnoea and other diseases causing excess daytime fatigue, by measuring the receding of excess daytime fatigue.



Our sleep centre uses sleep test devices that allow us to perform clinical and scientific research diagnostics: Philips Respironics Alice 6 LdxS diagnostic system.



The procedure is performed on the day after polysomnography, or the sleep test, in the sleep centre, normally between 9.00-18.00.

Alcohol or drinks with caffeine are not allowed to be consumed the evening before or on the test day.

A  drug test may be done  on the examinee  during the morning of the procedure. The drug test ensures that the MWT results are accurate. Several drugs could influence the test results. The drug test results are private and shall remain between the examinee and treating physician.



The MWT procedure consists of four forty-minute recordings; there are two-hour breaks between the test periods.

During the procedure, the sensors record electrical activity in the brain, eye movements, and muscle tone.

The examinee shall be asked to (without physical activity) try to remain awake while sitting in a darkened room.

The first recording starts 1.5-3 hours after waking up in the morning. The recordings shall typically be performed at 10.00, 12.00, 14.00, and 16.00.

10 minutes before the starting of the next recording, the patient shall take off his shoes, remove any tight clothing and sit on the bed. The sitting angle should be 45-90 degrees, while leaning on the headboard (armchair), so the neck muscles are not tight. The back is supported with a pillow or pillows. Legs are extended and slightly bent at the knee.

The test room shall be darkened with curtains before the test, dim lighting shall be switched on.

The electrodes shall be removed by the end of the fourth recording.

Laying on the bed between recordings is not permitted.

The examinee shall wear comfortable casual clothing during the procedure.

During the procedure, several questionnaires need to be filled in and the centre staff shall issue guidelines about related activities. The sleep technologist shall check the sensor attachments in order to ensure good quality for the procedure.

The examinee shall be offered breakfast, lunch, and snacks in the sleep centre.

The examinee is not allowed to exit the test rooms during the procedure.


Additional information:

In case the patient has already been diagnosed with sleep apnoea, he shall be asked to take his own APAP treatment device and mask, so the patient would feel comfortable at night.

Smokers should abstain from smoking for at least 30 minutes before the beginning of the next recording.



The sleep doctor shall inform you about the sleep test results during your return visit. The sleep centre administrator shall book you an appointment for this purpose.



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