Multiple wakefulness test

The multiple wakefulness test (MWT) is a method of apparatus-based performance diagnostics in sleep medicine and is also called the " Maintenance of Wakefulness Test " in the English original . It helps in the diagnosis of sleep disorders to record daytime sleepiness .

During the measurement, the patient or test person sits in a low-stimulus environment in dim light and should try to stay awake as long as possible. Sensors register whether he is falling asleep. The process consists of several rounds of a given duration, which are repeated in a time interval. There are several variants of the MWT, 20 or 40 minutes per round with four rounds at two-hour intervals.

Conducting the investigation

There are recommendations for carrying out this investigation, which serve the uniform application and comparability and are based on the work of Karl Doghramji.

The examination is carried out in a sleep laboratory because of the measurement technology required . The practitioners should have experience with this test. Whether a polysomnography in the previous night and a sleep diary are required for the time before this examination depends on the purpose of the examination.

After various variants of this test have been developed and evaluated over the course of time, it is now recommended to perform four rounds according to the 40-minute protocol at two-hour intervals from 9 or 10 a.m.

preparation

A light breakfast at least an hour before the first run is recommended. A light lunch is planned after the end of the second round. The consumption of tobacco and caffeine immediately before and during the MWT should be avoided. The use of medication also has an effect on drowsiness and requires consultation with the doctor.

The room should be completely darkened and have a single, well-defined, weak source of light behind the subject's head. The room temperature should be suitable for the subject's well-being. The test person should sit leaning against the bed with the head supported by a neck roll.

Measurement

In order to keep distractions small, all actions of the implementers and the instructions to the test subjects are standardized. Before each visit, the test person is asked whether they still need to go to the toilet or whether adjustments are necessary for their well-being. The sensors are then calibrated and the test subject is asked to make certain movements with their eyes. At the beginning of the measurement, the test person is asked to sit still, keep his eyes open and look ahead and stay awake as long as possible and not keep himself awake with actions such as singing, pinching or standing up.

Common recording of MWT includes electroencephalography (EEG), electrooculography (EOG) for both eyes, electromyography (EMG), and electrocardiogram (EKG).

evaluation

As is customary in polysomnography, the measurements recorded during the MWT are evaluated in 30-second epochs, calculated from the beginning of the respective recording. The beginning of sleep is the first epoch in which more than 15 seconds of sleep are determined. If no sleep occurs, the cycle ends after 40 minutes, otherwise after “definite sleep”, defined as three consecutive epochs in sleep stage N1 or an epoch in another sleep stage. Sleep latency is the time until you start to sleep or 40 minutes if you haven't been sleeping.

The result includes the following information: the time of the beginning and end of each round, sleep latency, the total sleep duration and the sleep stages achieved in the rounds, as well as the mean sleep latency as the arithmetic mean of the four rounds. Deviations from the standard protocol and special features should also be documented.

Differences to the multiple sleep latency test

Significant differences to the multiple sleep latency test (MSLT) are therefore the subject's posture (here sitting opposite), the support for the posture of the head (here lying slightly opposite on a pillow), the eyes (here openly closed), the brightness in the Room (here twilight versus darkening) as well as the default (here “stay awake” versus “fall asleep”).

A subject's ability to relax quickly can help them fall asleep faster. In healthy people it happens that they regularly fall asleep with a short latency with MSLT and can stay awake with MWT.

application

The MWT is one of the most popular apparatus-based procedures for performance diagnostics in sleep medicine worldwide. It is used to diagnose narcolepsy and to objectify hypersomnias . It is used to determine the severity of daytime sleepiness, but not to diagnose exclusion. Tonic activation and the ability to stay awake are examined.

Standard values for this test were determined for various sleep disorders and age groups.

" Nodding off " (Micro Sleep) is not detected in the standard protocol of the MWT, since episodes are not recognized under 15 seconds in the evaluation in the intended 30-second epochs.

A prediction by means of MWT regarding the falling asleep of individuals in real life is not possible.

According to a survey by the German Society for Sleep Research and Sleep Medicine (DGSM) in more than 300 sleep laboratories, around 40% said they used this test. It was used in connection with the diagnosis of hypersomnia, narcolepsy and sleep-related breathing disorders, as well as for testing professional drivers and for therapy control. This survey from 2009 shows an increasing prevalence of the test compared to 2004.

Alternatives

To determine the severity of daytime sleepiness, a multitude of methods are used in sleep medicine and other areas, depending on the issue. The MSLT belongs to the instrument-based diagnosis, the Epworth Sleepiness Scale (ESS), the Stanford Sleepiness Scale (SSS) and many other questionnaires belong to the non-instrumental diagnosis .

The “OSLER test” or “ Oxford Sleep Resistance Test ” is a behavior-oriented version of the MWT, in which the reaction time to LED signals is also examined.

history

The MWT was developed from the MSLT in 1982.

With MSLT, the latency to sleep is determined in a low-stimulus environment after being asked to fall asleep. This test is based on the assumption that higher physiological sleepiness leads to shorter sleep latency. In severe cases of daytime sleepiness, it was observed that no clinically significant differences in the MSLT could be found in the control of therapy attempts, although the patients subjectively reported improvements in questionnaires such as SSS. With this group of people, there is the problem of maintaining wakefulness in everyday situations during a phase of inactivity. This view led to the development of the MWT as a modification of the MSLT with the instruction to stay awake during the test.

Compared to MSLT, sleep latency increases when patients are instructed to stay awake. In narcolepsy, which was examined more closely at the time, the patients' latency to sleep was lower than in the control group, but the self-assessment in the questionnaire of feeling more awake did not always agree with the measurements.

Individual evidence

↑ Michael R. Littner et al., Standards of Practice Committee of the American Academy of Sleep Medicine: Practice Parameters for Clinical Use of the Multiple Sleep Latency Test and the Maintenance of Wakefulness Test . In: Sleep . Vol. 28, No. 1 , 2005, p. 113-121 , PMID 15700727 (English).
↑ ^a ^b Karl Doghramji, Merrill M. Mitler, Colin Shapiro et al: A normative study of the maintenance of wakefulness test (MWT) . In: Electroencephalography and Clinical Neurophysiology . Vol. 103, No. 5 , 1997, pp. 554-562 , PMID 9402886 (English).
^ ^A ^b Donna Arand, Michael Bonnet, Thomas Hurwitz et al: The Clinical Use of the MSLT and MWT . In: Sleep . Vol. 28, No. 1 , 2005, p. 123-144 , PMID 15700728 (English).
^ Murray W. Johns: Sensitivity and specificity of the multiple sleep latency test (MSLT), the maintenance of wakefulness test and the Epworth sleepiness scale: Failure of the MSLT as a gold standard . In: Journal of Sleep Research . Vol. 9, No. 1 , 2000, pp. 5–11 , doi : 10.1046 / j.1365-2869.2000.00177.x , PMID 10733683 (English).
↑ Cornelia Sauter, Heidi Danker-Hopfe: Multiple Sleep Latency Test . In: Somnology . 2013, doi : 10.1007 / s11818-012-0598-1 (English).
↑ ^a ^b S3 guideline for non-restful sleep / sleep disorders of the German Society for Sleep Research and Sleep Medicine (DGSM). In: AWMF online (as of 2009).
↑ ^a ^b Shannon S. Sullivan, Clete A. Kushida: Multiple Sleep Latency Test and Maintenance of Wakefulness Test . In: Chest . Vol. 134, No. 4 , 2008, p. 854–861 , doi : 10.1378 / chest.08-0822 (English).
↑ Cornelia Sauter, Heidi Danker-Hopfe: The Multiple Wachbleibetest (MWT) . In: Somnology . Vol. 14, No. 3 , 2010, p. 170-177 , doi : 10.1007 / s11818-010-0454-0 .
↑ Azmeh Shahid, Kate Wilkinson, Shai Marcu, Colin M. Shapiro: STOP, THAT and One Hundred Other Sleep Scales . Springer, New York 2012, ISBN 978-1-4419-9892-7 , doi : 10.1007 / 978-1-4419-9893-4 .
↑ ^a ^b Merrill M. Mitler, Krishnareddy S. Gujavarty, Carl P. Browman: Maintenance of wakefulness test: A polysomnographic technique for evaluating treatment efficacy in patients with excessive somnolence . In: Electroencephalography and Clinical Neurophysiology . Vol. 53, No. 6 , 1982, pp. 658-661 , doi : 10.1016 / 0013-4694 (82) 90142-0 , PMID 6177511 (English).

[AASM2005-1] Michael R. Littner et al., Standards of Practice Committee of the American Academy of Sleep Medicine: Practice Parameters for Clinical Use of the Multiple Sleep Latency Test and the Maintenance of Wakefulness Test . In: Sleep . Vol. 28, No. 1 , 2005, p. 113-121 , PMID 15700727 (English).

[Doghramji1997-2] Karl Doghramji, Merrill M. Mitler, Colin Shapiro et al: A normative study of the maintenance of wakefulness test (MWT) . In: Electroencephalography and Clinical Neurophysiology . Vol. 103, No. 5 , 1997, pp. 554-562 , PMID 9402886 (English).

[Arand2005-3] A ^b Donna Arand, Michael Bonnet, Thomas Hurwitz et al: The Clinical Use of the MSLT and MWT . In: Sleep . Vol. 28, No. 1 , 2005, p. 123-144 , PMID 15700728 (English).

[Johns-4] Murray W. Johns: Sensitivity and specificity of the multiple sleep latency test (MSLT), the maintenance of wakefulness test and the Epworth sleepiness scale: Failure of the MSLT as a gold standard . In: Journal of Sleep Research . Vol. 9, No. 1 , 2000, pp. 5–11 , doi : 10.1046 / j.1365-2869.2000.00177.x , PMID 10733683 (English).

[5] Cornelia Sauter, Heidi Danker-Hopfe: Multiple Sleep Latency Test . In: Somnology . 2013, doi : 10.1007 / s11818-012-0598-1 (English).

[S3DGSM-6] S3 guideline for non-restful sleep / sleep disorders of the German Society for Sleep Research and Sleep Medicine (DGSM). In: AWMF online (as of 2009).

[Kushida2008-7] Shannon S. Sullivan, Clete A. Kushida: Multiple Sleep Latency Test and Maintenance of Wakefulness Test . In: Chest . Vol. 134, No. 4 , 2008, p. 854–861 , doi : 10.1378 / chest.08-0822 (English).

[DGSM2010-8] Cornelia Sauter, Heidi Danker-Hopfe: The Multiple Wachbleibetest (MWT) . In: Somnology . Vol. 14, No. 3 , 2010, p. 170-177 , doi : 10.1007 / s11818-010-0454-0 .

[9] Azmeh Shahid, Kate Wilkinson, Shai Marcu, Colin M. Shapiro: STOP, THAT and One Hundred Other Sleep Scales . Springer, New York 2012, ISBN 978-1-4419-9892-7 , doi : 10.1007 / 978-1-4419-9893-4 .

[Mitler1982-10] Merrill M. Mitler, Krishnareddy S. Gujavarty, Carl P. Browman: Maintenance of wakefulness test: A polysomnographic technique for evaluating treatment efficacy in patients with excessive somnolence . In: Electroencephalography and Clinical Neurophysiology . Vol. 53, No. 6 , 1982, pp. 658-661 , doi : 10.1016 / 0013-4694 (82) 90142-0 , PMID 6177511 (English).