The qualitative presence of microsleep during the Multiple Sleep Latency Test (MSLT) has been shown to correlate with an increased incidence of subjective complaints of sleepiness, tiredness, accidents/near accidents, and gap driving. However, there is no data as to how to quantify microsleep and effectively incorporate it as a diagnostic tool in the measurement of sleepiness. The purpose of this study is to integrate microsleep to the MSLT score and determine if it improves the correlation between the MSLT and symptomatic sleepiness.
The charts of 54 patients who had an MSLT score of greater than 5 minutes and the presence of microsleep on at least one nap were reviewed. If microsleep was present in a given nap it was used as a surrogate for sleep onset. This MSLT plus microsleep score (MSLT+) was then averaged into the total sleep latency and compared with the MSLT score to determine if it improves correlation with the ESS.
Using the Spearman correlation the MSLT+ improved the association between ESS when compared to MSLT (r=0.106 versus r=0.063), but the results were not statistically significant. Of note, both the MSLT and MSLT+ were only weakly correlated to the ESS.
The addition of microsleep onset to the MSLT score as a quantitative assessment tool failed to significantly enhance the correlation between subjective and objective accounts of sleepiness, beyond the improvement seen in the MSLT value by the simple presence of microsleep alone.
The use of microsleep as a marker of excessive daytime sleepiness has been previously demonstrated, as has its qualitative presence as an enhancement to the MSLT score. Its clinical significance in daily life also can not be overstated, as it has been labeled as contributory in multiple large accidents and catastrophes. This study attempted to determine its exact implication on the way sleepiness is quantified; however the “holy grail” of accurately correlating objective sleep propensity to symptomatic excessive daytime sleepiness continues to elude us.
Allen Blaivas, None.