Pathophysiologically correlated deficits of information processing in obstructive sleep apnea patients.

In obstructive sleep apnea patients, who intermittently stop breathing at night for some seconds, functions of vigilance and attention seem to be impaired. The aim of our study was to investigate if nocturnal hypoxia as one possible detrimental factor is associated with the degree of modality shift effect expressing attention function at a very basic level of information processing. For the first time an experimental approach was applied to examine attention deficits in sleep apnea patients. Correlation analyses between pathophysiological parameters and attention function revealed a stronger association for the modality shift effect than for simple reaction times.

Adrenocortical responses to repeated parachute jumping and subsequent h-CRH challenge in inexperienced healthy subjects.

The present study examined the adrenocortical response to 3 consecutive parachute jumps and a poststress h-CRH challenge. Fifteen participants in a parachute-jumping course took saliva samples for later cortisol analysis every 20 min throughout the day, when they accomplished their very first 3 parachute jumps and throughout a control day. The effects of an h-CRH challenge on salivary cortisol were assessed in the evening of the jumping day and on a control day. Parachute jumping induced 3 distinct highly significant adrenocortical responses. The respective cortisol increases for the first, second, and third jump were 39.4 +/- 26.5 nmol/1, 31.4 +/- 21.4 nmol/l, and 16.5 +/- 11.9 nmol/l. Cortisol responses to the first and second jump did not differ but the response to the third jump was significantly reduced [t(13) = 3.11; p = 0.008]. Two groups of subjects were identified, "decreasers," whose response decreased from one to the other jump, and "increasers," whose response remained unchanged or increased. The magnitude of the preceding cortisol response of decreasers exceeded that of increasers significantly by about 30 nmol. The mean adrenocortical effects of the poststress h-CRH challenge and the time-matched challenge on a control day did not differ although, in 4 subjects, the poststress adrenocortical response to h-CRH was completely suppressed.

[Assessment of attention parameters in sleep apnea patients]. / Erfassung von Aufmerksamkeitsfunktionen bei Schlafapnoepatienten.

In the current study the modality-shift paradigm was applied to examine attention deficits in sleep-apnea patients. The reaction times of ipsi- and crossmodal light and sound stimuli were measured on 34 patients presenting symptoms of sleep-apnea. Some of the simple reaction times of ipsimodal (light-light; sound-sound) and crossmodal (light-sound; sound-light) stimuli correlated with mean or with minimal oxygen saturation, but did not correlate with the frequency or duration of obstructive apneas and hypopneas. However, results are different if the amount of modality-shift effect is taken into consideration. Significant correlations were found for the maximal duration of obstructive apneas and hypopneas as well as for mean oxygen saturation.