Ear-EEG for sleep assessment: a comparison with actigraphy and PSG

Purpose To assess automatic sleep staging of three ear-EEG setups with different electrode configurations and compare performance with concurrent polysomnography and wrist-worn actigraphy recordings. Methods Automatic sleep staging was performed for single-ear, single-ear with ipsilateral mastoid, and cross-ear electrode configurations, and for actigraphy data. The polysomnography data were manually scored and used as the gold standard. The automatic sleep staging was tested on 80 full-night recordings from 20 healthy subjects. The scoring performance and sleep metrics were determined for all ear-EEG setups and the actigraphy device. Results The single-ear, the single-ear with ipsilateral mastoid setup, and the cross-ear setup performed five class sleep staging with kappa values 0.36, 0.63, and 0.72, respectively. For the single-ear with mastoid electrode and the cross-ear setup, the performance of the sleep metrics, in terms of mean absolute error, was better than the sleep metrics estimated from the actigraphy device in the current study, and also better than current state-of-the-art actigraphy studies. Conclusion A statistically significant improvement in both accuracy and kappa was observed from single-ear to single-ear with ipsilateral mastoid, and from single-ear with ipsilateral mastoid to cross-ear configurations for both two and five-sleep stage classification. In terms of sleep metrics, the results were more heterogeneous, but in general, actigraphy and single-ear with ipsilateral mastoid configuration were better than the single-ear configuration; and the cross-ear configuration was consistently better than both the actigraphy device and the single-ear configuration.

Automated summary

The study evaluated the automatic sleep staging performance of three ear-EEG setups with different electrode configurations compared to polysomnography and actigraphy recordings. Results showed that the cross-ear setup had the highest kappa value of 0.72 for five class sleep staging, outperforming both the single-ear and single-ear with ipsilateral mastoid setups. In terms of sleep metrics, both the single-ear with ipsilateral mastoid and cross-ear configurations showed better performance compared to the actigraphy device and current state-of-the-art actigraphy studies.