Evaluating the Relationship Between Sleep-Disordered Breathing and Daytime Alertness

Primary Outcomes (3)

• Subjective Sleepiness

  Measured using the Epworth sleepiness scale (ESS). The Epworth sleepiness scale is used in the assessment of daytime sleepiness and measures the general level of sleepiness.The ESS presents the subject with eight situations and asks how likely they are to fall asleep (0= never, 1 =slight chance of dozing, 2= moderate chance of dozing and 3 =high chance of dozing) in these situations. The sum of the 8 answers is used as the score and ranges from 0 (not sleepy) to 24 (extremely sleepy), and a score of greater than 10 is an indication that a person may be excessively sleepy.

  Baseline, CPAP( 4 -6 weeks), Off CPAP ( 2 nights)

• Objective Sleepiness

  Multiple Sleep Latency Test (MSLT) measures the latency to sleep onset in minutes. The shorter the latency to sleep the more sleepy the subject.

  Measured at baseline, on CPAP (4-6 weeks), CPAP withdrawal (2 nights)

• Vigilance

  Vigilance is measured using the psychomotor vigilance task which is a portable reaction time test that is contained in a small, programmable, portable electronic box that requires only a single switch to start. The task consists of responding to a small bright red light stimulus by pressing a response button as soon as the stimulus appears. This stops the stimulus counter and displays the reaction time (RT) in milliseconds for a 2-second period and the task duration is 20 minutes. The subject is instructed to press the button as soon as each stimulus appears in order to keep the reaction time as low as possible. The PVT yields highly informative metrics on the capacity for sustained attention including the frequency of lapses (reaction time \> 500 milliseconds). The higher the number of lapses the greater the impairment. Well rested (non-sleepy) subjects have almost no lapses(\<2) during the 20min test.

  Baseline, CPAP (4-6 weeks), CPAP withdrawal (2 nights)

Conditions