Maintenance of Wakefulness Test, obstructive sleep apnea syndrome, and driving risk.
Ann Neurol.. 2008-08-07; 64(4): 410-416
DOI: 10.1002/ana.21448
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1. Ann Neurol. 2008 Oct;64(4):410-6. doi: 10.1002/ana.21448.
Maintenance of Wakefulness Test, obstructive sleep apnea syndrome, and driving
risk.
Philip P(1), Sagaspe P, Taillard J, Chaumet G, Bayon V, Coste O, Bioulac B,
Guilleminault C.
Author information:
(1)Université Bordeaux 2, Paris, France.
OBJECTIVE: Sleepiness at the wheel is a major risk factor for traffic accidents.
Because of the potential medical and legal implications, in this study, we
evaluated the correlation between subjective and objective measures of sleepiness
and driving performances in patients suffering from excessive daytime sleepiness.
METHODS: Thirty-eight untreated sleep apnea patients (mean age +/- standard
deviation, 51 +/- 9 years; mean apnea-hypopnea index +/- standard deviation, 41
+/- 25), and 14 healthy control subjects (mean age +/- standard deviation, 46 +/-
9 years) were included in the study. Nocturnal polysomnography, mean sleep
latency as measured by four 40-minute Maintenance of Wakefulness Test (MWT)
trials, Epworth Sleepiness Scale, Karolinska Sleepiness Scale, and the number of
inappropriate line crossings during a 90-minute real-life driving session were
analyzed.
RESULTS: The number of inappropriate line crossings correlated with MWT scores
(Spearman’s Rho: r = -0.339; p < 0.05), Karolinska Sleepiness Scale scores
measured at halfway in total driving distance (Rho: r = 0.367; p < 0.01), and
Epworth Sleepiness Scale (Rho: r = 0.389; p < 0.01). We found a significant
difference in the number of inappropriate line crossings among the four groups
defined by MWT scores (very sleepy [0-19 minutes], sleepy [20-33 minutes], alert
[34-40 minutes], and controls) (Kruskal-Wallis test: H = 11.319; p < 0.01). Very
sleepy and sleepy patients had more inappropriate line crossings than the control
drivers (p < 0.05).
INTERPRETATION: In addition to subjective sleepiness scales, the MWT can be used
to assess driving ability in untreated sleep apnea patients.
DOI: 10.1002/ana.21448
PMID: 18688799 [Indexed for MEDLINE]