Maintenance of Wakefulness Testing

Submitted by Karen Allen, RPSGT

PURPOSE:

Quantitative measurement to determine how long wakefulness can be maintained.

GENERAL CONSIDERATIONS:

1. A sleep diary is completed by the patient for one to two weeks prior to diagnostic nocturnal Polysomnogram.
2. Medication and drug history is obtained during the initial sleep center visit and verified at the time of the sleep study. Stimulants and antidepressants are discontinued for two weeks prior to testing whenever possible.
3. In the presence of, or acute withdrawal from stimulants, sedatives, REM suppressants, antihistamines, alcohol or excessive caffeine intake, the study will be canceled. Exceptions may be made by the responsible Sleep Center physician. In these cases, the substance use is documented and the rationale for the study is provided in the MWT report.
4. The MWT should be performed the day following a clinical nocturnal Polysomnogram. This provides for accurate documentation of the night's sleep, ruling out apnea, insomnia, myoclonus and other sleep disturbances, which is essential in patient assessment.
5. Sleep should be undisturbed and approximate the normal sleep pattern on the night prior to the MWT.
6. Patient should dress in street clothes before the MWT.
7. The amount of sleep obtained on the night preceding the MWT must be estimated prior to initiating the MWT. The daytime test may not be performed if the amount of sleep is substantially reduced from the patient’s normal patterns.
8. An MWT consists of four daytime trials, each lasting up to 40 minutes. Trials are scheduled at two-hour intervals.
9. Patients must abstain from caffeinated beverages and foods on the morning of the MWT and between test trials.

POLICY:

1. A urine drug screen is obtained on the morning of the MWT.
2. Equipment calibrations are performed prior to initiating the MWT and at the conclusion of the study.
3. Patient calibrations are performed prior to each daytime test trial.

PROCEDURE:

1. Obtain urine specimen prior to initiating MWT.
2. The patient preparation, electrode placement, and computer calibrations are defined and described in the Nocturnal Polysomnography Policy and Procedure.
3. Select montage for standard MSLT/MWT.
4. RECORDING MONTAGE

   EEG = C4 - A1 O2-A1

   C3 - A2 O1-A2

   EOG = F4 - A1 (Right outer canthus)

   F3 - A2 (Left outer canthus)

   EMG = EMG5-EMG6 (Right and left submentalis)

   PZ (Additional reference)

   EKG = ECGa - ECGr

5. The test should be performed as a controlled and consistent procedure.
6. Initiate the first daytime nap trial one and one-half to two hours from the termination of the nocturnal Polysomnogram.

1. 1. A quiet and dark room, with minimal noise interruptions should be used.
   2. The patient should be in the chair 10 minutes before the start of the trial.
   3. Perform Stanford Sleepiness Scale on the "MWT" pre trial questionnaire. Ask patient for his
   4. subjective opinion of his alertness
   5. Perform patient calibrations.
   6. Instruct the patient to remain quiet and resist sleep without any form of stimulation such as whistling, singing, pinching one self, tapping feet or bouncing legs.
   7. Once these instructions have been given, turn the lights off and the test is begun.
   8. Begin monitoring by selecting "Run" and enter patient's name in comment file.
   9. Documentation of any noise interruption, especially those producing stimulation should be
   10. entered in Comment file.
   11. Terminate trials using the following criteria:

Terminate the trial after three (3) consecutive epochs of unequivocal stage one sleep or one epoch of any other sleep stage OR

after 40 minutes of recorded time.

Perform the post-trial questionnaire. Ask patient if (s)he slept and if so for how long did (s)he sleep.

1. Repeat steps E1 through E9 at two-hour intervals for a total of four trials.
2. Between tests the patient must be out of bed and prevented from falling asleep between trials.

Smoking is not permitted and vigorous activity should be avoided within 15 minutes of the trial.

Continual observation between trials is essential.

No caffeine should be ingested the day of the test.

DOCUMENTATION:

1. Complete patient information file prior to start of "MWT" procedure.
2. Complete the Stanford Sleepiness scale before each trial.
3. Complete the MWT Patient Questionnaire after each trial.

SCORING:

1. The sleep latency is scored on the first epoch of stage one or any other sleep stage.
2. Four trials will be completed even if patient has documented sleep in a trial
3. Pt fails the MWT if fifteen (15) seconds of sleep is documented in any of the trials.