Daytime Sleepiness and Cognitive Functioning in Sleep ApneaMitler, Merrill, M.
doi: 10.1093/sleep/16.suppl_8.S68pmid: 8178031
Summary: Our earliest findings relating sleepiness to cognitive function revealed that, among patients with the symptom of excessive somnolence, sleep apneics were the most impaired on cognitive tasks. Although the multiple sleep latency test (MSLT) has been the standard diagnostic test for assessing daytime sleepiness, the maintenance of wakefulness test (MWT) has clinical advantages over the MSLT when the assessment of daytime alertness is the primary goal. A number of studies on patients with sleep apnea and narcolepsy indicate that the MWT is more sensitive to treatment-related improvements in sleepiness. However, sleep tendency, as measured by the MSLT, and ability to remain awake, as measured by the MWT, probably represent the same physiological process viewed from different perspectives. Some patients, particularly those who have received suboptimal treatment, will show no treatment-related improvement in daytime sleepiness if they are evaluated only by the MSLT. We believe that the MWT and MSLT measure different aspects of the central problem of abnormal sleep tendency. The MWT may be a useful adjuvant daytime test in clinical situations where it is necessary to quantify degree of impairment or effectiveness of treatment. Sleepiness, Performance, Sleep apnea, Narcolepsy, Treatment changes This content is only available as a PDF. © 1993 American Sleep Disorders Association and Sleep Research Society
The Predictive Accuracy of Home Oximetry in Patients With Suspected Obstructive Sleep ApneaKeenan, S., P.;Anderson,, B;Wiggs,, B;Ryan, C., F.;Fleetham, J., A.
doi: 10.1093/sleep/16.suppl_8.S133pmid: 8178005
Summary: To evaluate the predictive accuracy of home oximetry, we have performed a questionnaire, physical examination and home oximetry on 96 patients with suspected obstructive sleep apnea (OSA) within 2 weeks of laboratory polysomnography. We have developed a predictive equation that includes questionnaire, anthropometric and home oximetry data to diagnose OSA. We could confidently diagnose OSA in 20% of patients and exclude OSA in 5% of patients based on this prediction model and the population distribution. Sleep apnea, Home oximetry, Prediction model This content is only available as a PDF. © 1993 American Sleep Disorders Association and Sleep Research Society
Regulation of Gene Expression by HypoxiaMillhorn, David, E.;Czyzyk-Krzeska,, Maria;Bayliss, Douglas, A.;Lawson, Edward, E.
doi: 10.1093/sleep/16.suppl_8.S44pmid: 7909954
Summary: The present study was undertaken to determine if gene expression for tyrosine hydroxylase (TH), the rate limiting enzyme in the biosynthesis of catecholamines, is regulated in the carotid body, sympathetic ganglia and adrenal medulla by hypoxia. We found that a reduction in oxygen tension from 21% to 10% caused a substantial increase (200% at 1 hour and 500% at 6 hours exposure) in the concentration of TH mRNA in carotid body type I cells but not in either the sympathetic ganglia or adrenal gland. In addition, we found that hypercapnia, another natural stimulus of carotid body activity, failed to enhance TH mRNA in type I cells. Removal of the sensory and sympathetic innervation of the carotid body failed to prevent the induction of TH mRNA by hypoxia in type I cells. Our results show that TH gene expression is regulated by hypoxia in the carotid body but not in other peripheral catecholamine synthesizing tissue and that the regulatory mechanism is intrinsic to type I cells. Carotid body, In situ hybridization, Messenger RNA, Oxygen, Tyrosine hydroxylase This content is only available as a PDF. © 1993 American Sleep Disorders Association and Sleep Research Society
Effects of 100% O2 Exposure on Hypoxic Ventilatory ResponseChowdhury, Mustaquim, F.;Masuda,, Atsuko;Nakamura,, Wataru;Honda,, Yoshiyuki
doi: 10.1093/sleep/16.suppl_8.S128pmid: 8178002
Summary: Comparison of the slope of progressive isocapnic hypoxia obtained with and without prior O2 exposure (termed + and −O2 runs, respectively) placed our subjects into two groups. Positive responders had a significantly lower slope in − O2 runs compared with similar runs in negative responders, but they also improved hypoxic ventilatory response (HVR) significantly after O2 exposure. Negative responders had a high −O2 slope that did not alter significantly after O2 exposure. We conclude that ambient air hypoxic depression is active in positive responders who are O2 sensitive. Progressive hypoxia, O2 exposure, Hypoxic depression This content is only available as a PDF. © 1993 American Sleep Disorders Association and Sleep Research Society
The Utility of Topographic EEG Mapping in Obstructive Sleep Apnea SyndromeWalsleben, Joyce, A.;O'Malley, Edward, B.;Bonnet,, Kenneth;Norman, Robert, G.;Rapoport, David, M.;Engleman, H., M.;Douglas, N., J.
doi: 10.1093/sleep/16.suppl_8.S76pmid: N/A
Summary A study was undertaken to determine whether topographic brain mapping of standard EEG and cognitive evoked potentials would provide additional information for the detection of subtle brain abnormalities associated with obstructive sleep apnea. During nocturnal sleep, significant brain activity was detected in frontal regions not usually monitored with standard sleep recordings. Moreover, preliminary results suggest that total brain activity decreased in association with apneic events and depth of 02 desaturation. Also, component asymmetry in the P300 waveform observed in brain areas not typically recorded improved with treatment. We conclude that the use of topographic mapping adds important information to the study of brain function during sleep and sleep apnea. Obstructive sleep apnea, Topographic brain mapping, Evoked potentials, EEG, Hypoxia This content is only available as a PDF.