Sleep Stability and Cognitive Function in Operational Extreme Environments

Transcription

1 Sleep Stability and Cognitive Function in Operational Extreme Environments Marc Ó Gríofa, MD PhD FAWM D O Keeffe, B Rai, R Thomas, K Cohen Aerospace Medical Association 84th Annual Scientific Meeting May 15th 2013

2 Disclosure Information 84th Annual ASMA Scientific Meeting Marc Ó Gríofa, MD PhD FAWM I have the following financial relationships to disclose: Grant/Research support from: ESA Prodex I will not discuss off-label use and/or investigational use in my presentation

3 Introduction Sleep Sleep in spaceflight and extreme environments Project CASPER Cardiac autonomic and hemodynamic activity Use and efficacy of cardiopulmonary coupling in an operational mission environment Subjective and objective measurements Missions Astrolab, FMARS, NEEMO, MDRS, EuroMars Results Discussion & Conclusions

4 Chronobiology Circadian pacemaker Bodyclock Stages of sleep Homeostatic synchronisation Body temperature, hormone production Activity of heart intrinsically linked to circadian rhythm Free running : hrs Substantial individual variation Environmental synchronisation Strongest cue (Zeitgeber) is sunlight Terran light pattern

5 Polysomnography

6 Sleep Disruption During Spaceflight Sleep disruption has been a common and important problem among astronauts on a routine basis Up to 50% crew took hypnotic medication on some shuttle flights Analysis of sleep on shuttle missions 25% experience dramatic impairment in quality/quantity Orbital dawn, loss of terran light pattern & circadian rhythm disentrainment Endogenous circadian pacemaker (ECP) Disentrained after ~ 100 days of spaceflight Average 6 hours sleep per night Sleep and circadian rhythms in orbiting astronauts Implications of restricted sleep schedule Progress 234 on Mir Extended missions beyond low earth orbit and long-term acclimation to an extraterrestial body Martian Sol hrs Manned mission to Mars Human spaceflight ground support

7 Previous Orbital Sleep Studies

8 Cardiopulmonary Coupling Using appropriate thresholds for high and low frequency coupling magnitudes and their ratios it is possible to detect Stable/Unstable sleep states Sleep spectrogram: Visual representation of sleep pattern HFC/NCAP - High frequency coupling ( Hz) Stable sleep LFC/CAP - Low frequency coupling ( Hz) Unstable sleep elfc/dsp - Elevated-LFC (Lo/Hi ratio >30 [>0.05 Hz] used to define areas of disrupted sleep within recordings) Narrow band coupling [elfc]: Central apnea Broad band coupling [elfc]: Obstructive apnea elfc/dsp Disrupted sleep pattern in the absence of pathology due to environmental factors

9 Sleep Spectrogram

10 Cardiac Autonomic Activity Monitoring Fitted LifeShirt monitoring system

11 Subjective Sleep Monitoring Adapted Pittsburgh Sleep Diary Important feedback on perceived stresses and individual quality of sleep Previously used during spaceflight Instrument in itself with separate waketime and bedtime components (pre- and post-sleep diaries) Shown to demonstrate the usefulness, validity and reliability of various measures from instruments Validity in agreeing with estimates of sleep timing and quality Sensitivity in detecting differences of individual parameters & across different physiological & behavioural states

12 Subjective Sleep Diary Pre-Sleep Diary Questions 1 How tired were you at the start of this shift? 2 How tired are you now at the end of this shift? 3 How hectic/busy was this shift? 4 How physically strenuous was your work today? 5 How mentally taxing was your work today? 6 How satisfied are you with work done this shift? 7 How tense do you feel now? 8 How sleepy do you feel now? 9 Were you troubled by sickness, headaches, pain, stiffness? Post-Sleep Diary Questions 2 Difficulty in falling asleep last night? 6 Sleep quality? 7 Mood on final wakeup? 8 Alertness (how well rested) on final wakeup?

13 Missions and Environments ISS (International Space Station) Astrolab Mission FMARS (Flashline Mars Arctic Research Station) Arctic Mars Long Duration Analogue Mission NEEMO (NASA Extreme Environments Mission Operations) NASA NEEMO Asteroid Analogue Mission onboard Aquarius Undersea Habitat MDRS (Mars Desert Research Station) Desert Mars Analogue Mission EuroMars ESA Desert Mars Analogue Mission

14 Astrolab Long Duration Spaceflight Mission

15 NEEMO Mission

16 Arctic/Desert Analogue Missions

17 CASPER Missions Subjective Sleep Diary

18 CASPER Missions - Sleep Diary Question Correlations LFC/CAP HFC/NCAP ECG-LF ECG-HF elfc/dsp LFC/CAP HFC/NCAP ECG-LF ECG-HF ise Pre Q Pre Q Pre Q Pre Q Pre Q Pre Q Pre Q Pre Q Pre Q Post Q Post Q Post Q Post Q8 Is the Question Significant ( > 0.1) elfc/dsp

19 CASPER Missions Cardiac Autonomic Measurements

20 CASPER Missions Cardiac Autonomic Measurement Correlations LFC/CAP HFC/NCAP elfc/dsp LFC/CAP HFC/NCAP Average ise ECG-LF ECG-HF Is ECG Significant ( > 0.5) elfc/dsp

21 Discussion 214 nights total over 5 missions Strong correlation between ECG HRV and CPC high frequency components over all missions Weak correlation between ECG HRV and CPC low frequency components over all missions Examination of individual nights ECG HRV measured 51 nights >0.8 in low frequency range CPC measured 1 night >0.8 in low frequency range Correlation for CPC measurements was also much stronger with subjective sleep diary measurements elfc/dsp 8 questions LFC/CAP 7 questions HFC/NCAP 7 questions ECG/LF 2 questions ECG/HF 3 questions

22 Conclusions Strong correlation between CPC and subjective sleep diary feedback Strong correlation between HF components of CPC and ECG HRV Weak correlation between LF components of CPC and HRV Examination of individual nights revealed high noise levels in all of nights measuring >0.8 (80%) in the low frequency range CPC has proven valuable in the monitoring of sleep disruption in space analogue and extreme environments Potential for use in future spaceflight and extreme environments missions Future research Further development of non-contact monitoring technology Repeat missions with much tighter control of operational conditions ensuring strict adherence to protocols with greater number of subjects Increased use of adjunct markers to ensure robust correlation across all environments

23 Acknowledgements Dr Derek O Keeffe Dr Robert Thomas ECE Department, University of Limerick University College Dublin Mission Crews NASA JSC & KSC (Aerospace medicine & BRL) ESA Roscosmos Beth Israel Deaconess University of Pittsburgh ninvasive Medical Technologies, Inc. Inomedic Health Applications, Inc. Biometricore, LLC.

24 Ad Astra Per Aspera