Wearable In-Ear Encephalography Sensor for Monitoring Sleep. Preliminary Observations from Nap Studies.
To date, EEG is the only quantifiable measure of the neural changes that define sleep. Although it is used widely for clinical testing, scalp-electrode EEG is costly and is poorly tolerated by sleeping patients.



This was a pilot study to assess the agreement between EEG recordings obtained from a new ear-EEG sensor and those obtained simultaneously from standard scalp electrodes.



Participants were four healthy men, 25 to 36 years of age. During naps, EEG tracings were recorded simultaneously from the ear sensor and from standard scalp electrodes. A clinical expert, blinded to the data collection, analyzed 30-second epochs of recordings from both devices, using standardized criteria. The agreement between scalp- and ear-recordings was assessed.



We scored 360 epochs (scalp-EEG and ear-EEG), of which 254 (70.6%) were scored as non-REM sleep using scalp-EEG. The ear-EEG sensor had a sensitivity of 0.88 (95% confidence interval [CI], 0.82-0.92) and a specificity of 0.78 (95% CI, 0.70-0.84) in detecting N2/N3 sleep. The kappa coefficient between the scalp- and the ear-EEG was 0.65 (95% CI, 0.58-0.73). As a sleep monitor (all non-REM sleep stages vs. wake), the in-ear sensor had a sensitivity of 0.91 (95% CI, 0.87-0.94) and a specificity of 0.66 (95% CI, 0.56-0.75). The kappa coefficient was 0.60 (95% CI, 0.50-0.69).



Substantial agreement was observed between recordings derived from a new ear-EEG sensor and conventional scalp electrodes on four healthy volunteers during daytime naps.
1 Communications and Signal Processing Group, Electrical and Electronic Engineering Department.
David
D
Looney
1 Communications and Signal Processing Group, Electrical and Electronic Engineering Department.
Valentin
V
Goverdovsky
2 Imperial College London, London, United Kingdom.|3 Sleep and Brain Plasticity Centre, Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College, London, United Kingdom.|4 Danish Epilepsy Centre, Dianalund, Denmark.|5 Sleep Disorders Centre, Guy's and St. Thomas' National Health Service Foundation Trust, London, United Kingdom.
Ivana
I
Rosenzweig
2 Imperial College London, London, United Kingdom.|6 Academic Unit of Sleep and Ventilation, National Heart and Lung Institute, London, United Kingdom; and.|7 National Institute for Health Research Respiratory Disease Biomedical Research Unit at the Royal Brompton and Harefield National Health Service Foundation Trust, London, United Kingdom.
Mary J
MJ
Morrell
1 Communications and Signal Processing Group, Electrical and Electronic Engineering Department.
Danilo P
0000-0001-8432-3963
DP
Mandic
D000328:Adult; D004569:Electroencephalography / Q000295:instrumentation*; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D010865:Pilot Projects; D012680:Sensitivity and Specificity; D012894:Sleep Stages / Q000502:physiology*; D006113:United Kingdom; D000076251:Wearable Electronic Devices
nocturnal EEG; obstructive sleep apnea; sleep; sleep-disordered breathing
Curr Protoc Neurosci. 2009 Oct;Chapter 10:Unit10.2
19802813
Am J Respir Crit Care Med. 2010 Jul 15;182(2):269-77
20339144
Sleep. 1991 Dec;14(6):540-5
1798888
Am J Respir Crit Care Med. 2010 Jul 1;182(1):98-103
20299536
IEEE Pulse. 2012 Nov-Dec;3(6):32-42
23247157
Fam Med. 2005 May;37(5):360-3
15883903
Am J Respir Crit Care Med. 2015 Jun 15;191(12):1450-8
26075423
J Neural Eng. 2014 Aug;11(4):046014
24963747
IEEE Trans Biomed Eng. 2013 Oct;60(10):2824-30
23722447
Conf Proc IEEE Eng Med Biol Soc. 2013;2013:543-6
24109744
Am J Respir Crit Care Med. 2009 Jul 1;180(1):36-41
19406983
Lancet Respir Med. 2015 May;3(5):404-14
25887982
JAMA. 2013 Mar 13;309(10):997-1004
23483174
Sleep. 2005 Jan;28(1):113-21
15700727
Chest. 2013 Jun;143(6):1569-75
23450315