Effects of Continuous Positive Airway Pressure Therapy in Moderate to Severe Obstructive Sleep Apnea: A High-density EEG Study
Authors List
D’Rozario, A. L.1,2; Kao, C.1 Phillips, C. L.1,3, Mullins, A. E.4; Memarian, N.1; Yee, B.J1,5,6; Duffy, S.1 Cho, G.1; Wong, K. K.1,5,6; Kremerskothen, K.1; Chapman, J.1; Haroutonian, C.1,2; Bartlett, D. J.1,6; Naismith, S. L.1,2; Grunstein, R. R.1,5,6.
1. CIRUS, Centre for Sleep and Chronobiology, Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.
2. School of Psychology, Faculty of Science, Brain and Mind Centre and Charles Perkins Centre, The University of Sydney, NSW, Australia.
3. Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, Australia.
4. Division of Pulmonary, Critical Care and Sleep Medicine, Icahn
School of Medicine, Mount Sinai, New York City, New York, USA.
5. Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
6. Sydney Medical School, Faculty of Medicine and Health University of Sydney, Sydney, Australia.
Study Objectives
Limited channel electroencephalography (EEG) investigations in OSA has
revealed deficits in slow wave activity (SWA) and spindles during sleep and increased EEG slowing during resting wakefulness. High-density EEG (Hd-EEG) has also found local parietal deficits in SWA (delta power) during NREM. It is unclear whether effective CPAP treatment reverses regional SWA deficits, and other regional sleep and wake EEG abnormalities, and whether any recovery relates to improved overnight memory consolidation.
Methods
A clinical sample of men with moderate-severe OSA underwent sleep and resting wake recordings with 256-channel Hd-EEG before and after 3 months of CPAP. Memory tasks were administered before and after sleep. Topographical spectral power maps of standard frequencies and differences between baseline and treatment were compared using t-tests and statistical nonparametric mapping (SnPM).
Results
In 11 compliant CPAP users (5.2±1.1 hours/night), total sleep time did not differ but N1 and N2 sleep were lower and N3 was higher after CPAP. During N3, we found a trend for increased parietal SWA after CPAP (uncorrected p=0.0029, SnPM p<0.09). However, N3 centro-parietal gamma power significantly increased and N2 fronto-central slow spindle activity decreased (both SnPM<0.05). The change in parietal N3 SWA with CPAP correlated with the change in overnight procedural memory consolidation (rho=0.79, p=0.03). During resting wakefulness, there were trends for reduced delta and theta power (SnPM p<0.09) .
Conclusions
Effective CPAP treatment of OSA may correct localised EEG abnormalities, and regional recovery of SWA may translate to memory improvements in the short-term.
Research Funding Source: This work was supported by research fellowships to ALD (NHMRCARC Dementia Research Development Fellowship GNT1107716 and NHMRC Emerging Leadership II Investigator Grant GNT2008001), CLP (NHMRC Dementia Leadership Fellowship GNT1139625), SLN (NHMRC Dementia Leadership Fellowship GNT1135639); and RRG
(NHMRC Senior Principal Research Fellowship GNT1106974).
D’Rozario, A. L.1,2; Kao, C.1 Phillips, C. L.1,3, Mullins, A. E.4; Memarian, N.1; Yee, B.J1,5,6; Duffy, S.1 Cho, G.1; Wong, K. K.1,5,6; Kremerskothen, K.1; Chapman, J.1; Haroutonian, C.1,2; Bartlett, D. J.1,6; Naismith, S. L.1,2; Grunstein, R. R.1,5,6.
1. CIRUS, Centre for Sleep and Chronobiology, Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia.
2. School of Psychology, Faculty of Science, Brain and Mind Centre and Charles Perkins Centre, The University of Sydney, NSW, Australia.
3. Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, Australia.
4. Division of Pulmonary, Critical Care and Sleep Medicine, Icahn
School of Medicine, Mount Sinai, New York City, New York, USA.
5. Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
6. Sydney Medical School, Faculty of Medicine and Health University of Sydney, Sydney, Australia.
Study Objectives
Limited channel electroencephalography (EEG) investigations in OSA has
revealed deficits in slow wave activity (SWA) and spindles during sleep and increased EEG slowing during resting wakefulness. High-density EEG (Hd-EEG) has also found local parietal deficits in SWA (delta power) during NREM. It is unclear whether effective CPAP treatment reverses regional SWA deficits, and other regional sleep and wake EEG abnormalities, and whether any recovery relates to improved overnight memory consolidation.
Methods
A clinical sample of men with moderate-severe OSA underwent sleep and resting wake recordings with 256-channel Hd-EEG before and after 3 months of CPAP. Memory tasks were administered before and after sleep. Topographical spectral power maps of standard frequencies and differences between baseline and treatment were compared using t-tests and statistical nonparametric mapping (SnPM).
Results
In 11 compliant CPAP users (5.2±1.1 hours/night), total sleep time did not differ but N1 and N2 sleep were lower and N3 was higher after CPAP. During N3, we found a trend for increased parietal SWA after CPAP (uncorrected p=0.0029, SnPM p<0.09). However, N3 centro-parietal gamma power significantly increased and N2 fronto-central slow spindle activity decreased (both SnPM<0.05). The change in parietal N3 SWA with CPAP correlated with the change in overnight procedural memory consolidation (rho=0.79, p=0.03). During resting wakefulness, there were trends for reduced delta and theta power (SnPM p<0.09) .
Conclusions
Effective CPAP treatment of OSA may correct localised EEG abnormalities, and regional recovery of SWA may translate to memory improvements in the short-term.
Research Funding Source: This work was supported by research fellowships to ALD (NHMRCARC Dementia Research Development Fellowship GNT1107716 and NHMRC Emerging Leadership II Investigator Grant GNT2008001), CLP (NHMRC Dementia Leadership Fellowship GNT1139625), SLN (NHMRC Dementia Leadership Fellowship GNT1135639); and RRG
(NHMRC Senior Principal Research Fellowship GNT1106974).
