Improving The Multiple Sleep Latency Test

General procedure, sleep environment, and bedside manners

A page that was recommended to me on a previous post inspired me to write an entry about the importance of getting a good sample of sleep data when using polysomnography (PSG).

The Multiple Sleep Latency Test (MSLT) is used as a diagnostic tool for sleep disorders (most commonly for narcolepsy). William Dement and Mary Carskadon designed it back in 1977.

Here is the typical procedure (summarized from this wiki page):

• Preparation: On the day of the test the patient is asked not to consume any stimulants (e.g., coffee, colas, etc).
• A formal sleep study might be performed the night before.
• Sometimes a urine screening is done to check for substances that might interfere with sleep.
• The patient fills out a pre-test questionnaire.
• Electrodes are attached to the patient’s head (EEG), eyes (EOG), and to the chin to detect muscle tone (EMG).
• Heart beat may be monitored (as well as breathing, depending on patient).
• The patient is asked to nap for 20 minutes, and then is awakened.
• The nap process is repeated every 2 hours for a total of four or five times.
• The patient may fill out a post-test questionnaire.

The point is to detect how readily and consistently the person will fall asleep in an ideal setting, as well as how they fall asleep — this test can be used to detect certain sleep disorders. For example, in the case of narcolepsy, REM sleep disturbance and excessive daytime sleepiness are characteristics of the disorder and can be detected with this test. I won’t get into narcolepsy too much, although it is both a fascinating and debilitating disorder (if left untreated), so I encourage anyone reading this to learn more about it if unfamiliar, as it is poorly understood. Here’s one resource for that.

What I do want to talk about is the test. It is supposed to conducive to falling asleep. In fact, the test is based on the idea that that the sleepier a person is, the faster they will fall asleep — which seems like a fair hypothesis.

However, anyone who has had their scalp and face covered in electrodes in a laboratory for any reason will tell you how uncomfortable it can be. From the conductive paste to the sheer number of wires that are involved, the experience is not one I’d consider conducive to sleep. However, these are necessary evils and cannot yet be avoided.

Here’s what can be avoided: the sleep lab. While it seems nice to be able to control the patient’s environment and do so in a location that is convenient for the clinician and sleep tech, from my experience it is not the best option. In many cases, a much better one is to bring the sleep lab to the patient, and this goes for both research and clinical work.

Testing in the patient’s home does require some changes, and I realize it is not always possible (e.g., in hospital settings with limited staff). However, it is worth the extra effort when it is possible. Here’s what we would do when we would test teens for a sleep study (keep in mind this was research, not clinical):

• A research assistant (RA) arrives at the participant’s home a couple hours before bedtime with the sleep tech.
• They develop a rapport with the teen and his/her parents to put them at ease.
• Have the participant fill out some questionnaires (consent and a structured interview had already been done on a different day at the lab).
• The sleep tech would attach the electrodes and set up the recording device.
• The sleep tech would leave, and the RA would stay until bedtime (in this case, the participant was being sleep deprived and had an exactly specified bedtime based off a previous week’s worth of measures, so an RA was necessary to ensure the appropriate bedtime).
• The next day, an RA would call to make sure the participant got up at a specified time (only applies for sleep dep study).
• The participant would come into the lab and an RA would remove the electrodes and administer more tests.

The point I’m getting at with this personal research example is that, with a few extra steps, it was entirely possible to perform quality research in an individual’s natural home environment. When it is necessary to use a slightly invasive test for sleep like PSG, whether experimental or clinical, this procedure can be incredibly beneficial. Any possible confounds like sleep hygiene can be examined with a few short questionnaires.

In the case of the MSLT, awakenings are necessary. These can be done via phone calls, texts, or any number of ways that suit the patient or participant. Alternatively, an RA could stay at the individual’s home throughout the test if all involved are comfortable with this. This brings me to my final point — one of the very necessary components to this kind of testing is good “bedside manners”. Considering that this person has trusted you to come into their home, I cannot stress this enough. If you want good adherence in research, or a positive relationship with your client or patient, it is vital to make sure that everyone involved can help make sure the individual never feels uncomfortable. This should stand for all interactions with participants/clients/patients, but is entirely necessary for those that take place in their home.

In the case that this isn't possible, then it makes more sense to conduct the sleep study in a lab.