Maintenance of wakefulness test as a predictor of driving performance in patients with untreated obstructive sleep apnea.
OBJECTIVE
To determine the ability of Maintenance of Wakefulness Test (MWT) to predict simulated driving performance in patients suffering from sleep apnea syndrome.


METHODS
Study involving one hour of simulated driving, one night of polysomnography (PSG), and a 4 x 40-minute MWT.


METHODS
Sleep laboratory.


METHODS
Thirty male patients with untreated obstructive sleep apnea syndrome (OSAS) (mean age [+/- SD] = 51 +/- 8 years, range 34-62; mean body mass index (BMI) [+/- SD] = 29 +/- 3, range 24-37; mean apnea/hypopnea index (AHI) [+/- SD] = 43 +/- 24, range 14-96). As defined by MWT mean sleep latency, 23.3% of the patients were sleepy (0-19 min), 33.3% were alert (20-33 min), and 43.4% were fully alert (34-40 min).


METHODS
Nocturnal PSG, mean sleep latency at 4 x 40-minute MWT trials, Epworth Sleepiness Scale (ESS), and standard deviation from the center of the road (SDS) on driving simulator.


RESULTS
Mean MWT scores inversely correlated with SDS during the simulated driving session (Pearson's r = -0.513, P < 0.01). We found a significant effect of MWT groups (sleepy, alert, or fully alert) on SDS (ANOVA, F(2, 29) = 5.861, P < 0.01). Post hoc tests revealed that the sleepy group had a higher SDS than the fully alert group (P = 0.006). ESS, AHI, microarousal index, and total sleep time did not predict simulated driving performance.


CONCLUSIONS
A pathological MWT mean sleep latency (0-19 min) is associated with simulated driving impairment. Before MWT can be used to predict the driving ability of untreated patients with OSAS, further studies are needed to confirm that pathological MWT scores are associated with real driving impairment.
Sagaspe
Patricia
P
Clinique du Sommeil, CHU Pellegrin, Bordeaux, France.
Taillard
Jacques
J
Chaumet
Guillaume
G
Guilleminault
Christian
C
Coste
Olivier
O
Moore
Nicholas
N
Bioulac
Bernard
B
Philip
Pierre
P
D000328:Adult; D001143:Arousal; D001334:Automobile Driving; D015992:Body Mass Index; D003198:Computer Simulation; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011930:Reaction Time; D012890:Sleep; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*; D014851:Wakefulness