MSLT

Question 1

What does MWT stand for?

Answer 1

Maintenance of Wakefulness Test

MWT is used to measure the ability to stay awake for a defined length of time.

Question 2

What are the indications for the MWT? (2)

Answer 2

If you are in an occupation involving public transportation or safety for their ability to remain awake.
E.g. pilot or HGV driver

It can also be an assessment of response to treatment (e.g. stimulants for narcolepsy)

Question 3

What does MSLT stand for?

Answer 3

Multiple Sleep Latency Test

MSLT measures an individual’s tendency to sleep.

Question 4

Name two conditions assessed by the MWT.

Answer 4

• Narcolepsy
• Idiopathic hypersomnolence

MWT is used to assess excessive sleepiness in various conditions.

Question 5

Define excessive sleepiness.

Answer 5

Sleepiness in a situation when an individual would usually be expected to be awake and alert

This can indicate underlying sleep disorders.

Question 6

What is the primary purpose of the MWT?

Answer 6

• Assessing ability to remain awake in safety-sensitive occupations
• Evaluating response to treatment for sleep disorders

MWT is crucial for individuals in roles like pilots and HGV drivers.

Question 7

What are the recording parameters for the MWT?

Answer 7

• EEG – bipolar montage
• Bilateral EOG
• ECG
• EMG

These parameters help monitor sleep and wakefulness during the test.

Question 8

What is the trial structure for the MWT?

Answer 8

• 4 x 40 minute trials
• 2 hour intervals
• Dim lit, sound proof room
• Asked to stay remain relaxed with eyes open
• Trial ends after 40 minutes in no sleep occurs, or sleep onset (3 continuous epochs of stage I sleep or 1 epoch of any other stage sleep)

Trials are conducted to assess wakefulness under controlled conditions.

Question 9

What indicates impairment in wake tendency in the MWT?

Answer 9

Mean sleep latency (SL) under < 8 minutes

A lower SL suggests significant difficulties in maintaining wakefulness.

Question 10

What indicates untreated narcolepsy in the MWT?

Answer 10

Mean sleep latency (SL) of 10 minutes

Question 11

What does the MSLT measure?

Answer 11

An individual’s tendency to sleep

MSLT provides a direct, objective measurement of sleep onset.

Question 12

What is considered mild sleepiness according to MSLT?

Answer 12

Episodes present only during rest or low attention activities

Associated with an MSLT mean sleep latency of 10 - 15 minutes.

Question 13

What is the mean sleep latency for severe sleepiness, moderate sleepiness and mild sleepiness?

Answer 13

Mild- 10-15 minutes
Moderate- 5 – 10 minutes
Severe- < 5 minutes

This level of sleepiness is regarded as pathological.

Question 14

What is the significance of SOREM periods in narcolepsy diagnosis?

Answer 14

2 or more SOREM periods found in at least 80% of narcolepsy patients

SOREM indicates sleep-onset REM periods, crucial for diagnosing narcolepsy.

Question 15

What MSLT features mean a positive result for narcolepsy

Answer 15

2 Trials with REM and <8 minutes sleep onset latency

Question 16

What is the minimum sleep requirement before conducting the MSLT?

Answer 16

> 6 hours sleep

Insufficient sleep prior to MSLT invalidates the results.

Question 17

What is the test environment for the MSLT?

Answer 17

Dark, sound proof room

This environment helps minimize distractions and promotes sleep onset.

Question 18

What is the duration of each nap opportunity in the MSLT?

Answer 18

20 minutes

The test ends if no sleep onset occurs within this time.

Question 19

What indicates a positive result for narcolepsy in the MSLT?

Answer 19

2 trials with REM and < 8 minutes SO latency

This combination confirms the diagnosis of narcolepsy.

Question 20

What should the MSLT report include?

Answer 20

• Start and end times of each nap
• Latency to first epoch of sleep
• Mean sleep latency
• Number of sleep-onset REM periods

Subjective reports of sleep duration and dreaming can also be helpful.