The obstructive sleep apnea syndrome (OSAS) involves recurrent sleep-related upper airways (UA) collapse. UA mechanical properties and neural control are altered, imposing a mechanical load on inspiration. UA collapse does not occur during wakefulness, hence arousal-dependent compensation. Experimental inspiratory loading in normal subjects elicits respiratory-related cortical activity during wakefulness. The objective of this study is to test whether awake OSAS patients would exhibit a similar cortical activity. Whether or not such cortical compensatory mechanisms have cognitive consequences would be also analyze.