Fatigue is a common but often an understated symptom in MS consultations. Good sleep hygiene is essential, whilst lifestyle changes incorporating regular cardiovascular exercise, omega-3 fatty acids and melatonin have all been shown to be helpful.
Driving on a normal day is highly stimulating for the brain and as a result depending on the length of drive (where the drive is conversely monotonous) is an added risk for those with neurological disorders.
“Subjective lack of physical and/or mental energy that is perceived by the individual or the caregiver to interfere with usual and desired activities.” (Multiple Sclerosis Guidelines for Clinical Practice and Guidelines, 1998)
“Inability to stay awake and alert during the major waking episodes of the day, resulting in periods of irrepressible need for sleep or unintended lapses into drowsiness or sleep” (American Academy of Sleep Medicine, 2014)
The features of sleepiness are characterized by changes in eye movement, eyelid behavior, head nodding and facial expression. By using a tool to assess eyelid closure or PERCLOS (the PERcentage of eyelid CLOsure) assessment, the team from Kansas City assessed vigilance and sleepiness during simulated driving in MS.
They found that monotonous driving like the ones encountered on highways was likely increase daytime sleepiness during driving in both MS and control individuals. However, in relative terms this was more at the end of the drive in MS (see figure below).
Overall, there was 33% prevalence of daytime sleepiness in the study, compared to 20% in the control participants (which was not statistically different). There was no direct correlation with disability levels or reported fatigue, suggesting that different domains may be involved in sleepiness during functional activities. However, these findings do point to an extra note of caution for those using highways for their commute.
Mult Scler Relat Disord. 2020 Oct 31;47:102607. doi: 10.1016/j.msard.2020.102607. Online ahead of print.
Real-time assessment of daytime sleepiness in drivers with multiple sclerosis
Background: Daytime sleepiness is a common symptom of multiple sclerosis (MS) that may jeopardize safe driving. Our aim was to compare daytime sleepiness, recorded in real-time through eyelid tracking, in a simulated drive between individuals with MS (iwMS) and healthy controls.
Methods: Fifteen iwMS (age = median (Q1 – Q3), 55 (50 – 55); EDSS = 2.5 (2 – 3.5); 12 (80%) female) were matched for age, sex, education, and cognitive status with 15 controls. Participants completed self-reported fatigue and sleepiness scales including the Modified Fatigue Impact Scale (MFIS), Pittsburg Sleep Quality Inventory (PSQI), and Epworth Sleepiness Scale (ESS). Percentage of eyelid closure (PERCLOS) was extracted from a remote eye tracker while completing a simulated drive of 25 min.
Results: Although iwMS reported more symptoms of fatigue (MFIS, p = 0.003) and poorer sleep quality (PSQI, p = 0.008), they did not report more daytime sleepiness (ESS, p = 0.45). Likewise, there were no differences between groups in real-time daytime sleepiness, indexed by PERCLOS (p = 0.82). Both groups exhibited more real-time daytime sleepiness as they progressed through the drive (time effect, p < 0.0001). The interaction effect of group*time (p = 0.05) demonstrated increased symptoms of daytime sleepiness towards the end of the drive in iwMS compared to controls. PERCLOS correlated strongly (Spearman ρ = 0.76, p = 0.001) with distance out of lane in iwMS.
Conclusion: IwMS show exacerbated symptoms of daytime sleepiness during a monotonous, simulate drive. Future studies should investigate the effect of MS on daytime sleepiness during real-world driving.