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Daytime sleepiness and driving in MS

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  1. The study in brief
  2. The study in more detail
  3. More about daytime sleepiness
  4. Browse more from the latest research

The study in brief

Daytime sleepiness is described as an inability to remain awake during the day and is considered to be distinct from fatigue. Although daytime sleepiness affects about one third of people with MS and can have a real impact on daily life, it is often overlooked in the clinic and in research. Monotonous driving can trigger daytime sleepiness so this study used a simulated drive to assess differences between people with and without MS.

Fifteen people with and fifteen people without MS were recruited by researchers at an MS clinic in the United States. They completed questionnaires on fatigue, quality of sleep and daytime sleepiness. They then completed a 25 minute boring drive on a simulator; to measure alertness during the drive, an eye tracker recorded the amount of time that their eyes were 80% to 100% closed (excluding blinks).

In both groups, daytime sleepiness increased during the course of the drive. However, people with MS experienced a greater increase in daytime sleepiness towards the end of the drive; people with MS closed their eyes an average 2.5% of the time at the end of the drive, compared to 1.5% for people without MS.

The results indicate that lack of mental stimulation from monotonous driving increases daytime sleepiness in people with and without MS, underlining the importance for both groups to take regular breaks while driving. People with MS show increased symptoms of daytime sleepiness towards the end of the drive compared to people without MS. Further studies with more participants and longer driving times are needed to confirm and build on these results.

The study in more detail

Background

Daytime sleepiness is described as an inability to remain awake during the day and is considered to be distinct from fatigue. Although daytime sleepiness affects about one third of people with MS and can have a real impact on daily life, it is often overlooked in the clinic and in research. Monotonous car driving can induce daytime sleepiness so this study used a simulated drive as a way to compare differences in susceptibility between people with and without MS.

How this study was carried out

Researchers at an MS clinic in the United States recruited 15 people with MS and 15 people without MS; all had a valid driver’s licence and were driving regularly at the time that they took part in the study. The participants were asked to complete questionnaires to rate their levels of fatigue and quality of sleep. They also completed the Epworth Sleepiness Scale (ESS) to assess daytime sleepiness. The ESS has eight questions which ask about the likelihood of falling asleep or dozing off (in comparison to just feeling tired) in different everyday situations, such as watching TV, sitting and reading, or talking to someone. The scores are in a range of 0-24 and a score greater than 10 indicates increased daytime sleepiness. Use this online version to find your own score.

Participants then completed a 25 minute monotonous simulated drive, similar to driving on motorways with low levels of traffic. When someone experiences a period of daytime sleepiness, their eyelid droops, so to measure alertness during the drive, a screen-mounted eye tracker recorded the amount of time that the eyes were 80% to 100% closed (excluding blinks).

What was found?

Responses to the questionnaires indicated that people with MS reported worse symptoms of fatigue and poorer sleep quality. Based on responses to the ESS questionnaire, 33% of people with MS experienced daytime sleepiness, compared to 20% of those without MS, although this was not statistically significant.

During the driving simulation, real-time daytime sleepiness, measured by eyelid closure, did not largely differ between the groups. In both groups, daytime sleepiness increased during the course of the drive. However, people with MS experienced a greater increase in daytime sleepiness towards the end of the drive; people with MS closed their eyes an average 2.5% of the time at the end of the drive, compared to 1.5 % for people without MS. In people with MS, eyelid closure was closely associated with disease duration and the total distance travelled out of the correct lane, either across the centre line or road edge.

What does it mean?

The researchers conclude that monitoring eyelid closure while driving provides a valuable real-time measure of daytime sleepiness in MS. The results indicate that lack of mental stimulation from monotonous driving increases daytime sleepiness in people with and without MS, underlining the importance for both groups to take regular breaks while driving. People with MS show increased symptoms of daytime sleepiness towards the end of the drive compared to people without MS. Further studies with more participants and longer driving times will be needed to confirm the results.

Devos H, et al.
Real-time assessment of daytime sleepiness in drivers with multiple sclerosis.
Mult Scler Relat Disord 2020 Oct 31; 47: 102607.
Read the full study

More about daytime sleepiness

Daytime sleepiness is defined as the “inability to stay awake and alert during the day, resulting in periods of irrepressible need for sleep or unintended lapses into drowsiness or sleep”. Although fatigue and daytime sleepiness are two different symptoms, they are related; higher levels of daytime sleepiness were often accompanied by higher levels of fatigue. Daytime sleepiness may be overlooked in someone who has fatigue, as it may be considered part of their fatigue, but could be a sign of poor sleep quality or sleep disorders such as sleep apnoea (abnormal pauses in breathing). Treating the underlying sleep problem could improve daytime sleepiness and potentially improve levels of fatigue too. Find out more about sleep problems and tips for improving sleep quality.

You can assess your level of daytime sleepiness using the Epworth Sleepiness Scale.

Find out more about driving and MS.

Browse more from the latest research

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