An average of 68.1 10.7 ( SE ) auditory stimuli were delivered to interrupt deep sleep during the disruption night , limiting deep sleep to only brief episodes ( average length disrupted 1.3 0.2 min vs normal 7.1 0.8 min , P < .001 ) , and increasing the number of transitions between non-rapid eye movement ( NREM ) , REM , and wake ( disrupted 274.5 33.4 vs normal 131.2 8.1 , P = .001 ) .