Comparing In-ear EOG for Eye-Movement Estimation With Eye-Tracking: Accuracy, Calibration, and Speech Comprehension

Martin A Skoglund; Martin Andersen; Martha M Shiell; Gitte Keidser; Mike Lind Rank; Sergi Rotger-Griful

doi:10.3389/fnins.2022.873201

Comparing In-ear EOG for Eye-Movement Estimation With Eye-Tracking: Accuracy, Calibration, and Speech Comprehension

Front Neurosci. 2022 Jun 30:16:873201. doi: 10.3389/fnins.2022.873201. eCollection 2022.

Authors

Martin A Skoglund^{1

2}, Martin Andersen³, Martha M Shiell², Gitte Keidser^{2

4}, Mike Lind Rank³, Sergi Rotger-Griful²

Affiliations

¹ Division of Automatic Control, Department of Electrical Engineering, The Institute of Technology, Linköping University, Linkoping, Sweden.
² Eriksholm Research Centre, Part of Oticon A/S, Snekkersten, Denmark.
³ T&W Engineering A/S, Allerød, Denmark.
⁴ Department of Behavioral Sciences and Learning, Linneaus Centre Head, Linköping University, Linkoping, Sweden.

Abstract

This presentation details and evaluates a method for estimating the attended speaker during a two-person conversation by means of in-ear electro-oculography (EOG). Twenty-five hearing-impaired participants were fitted with molds equipped with EOG electrodes (in-ear EOG) and wore eye-tracking glasses while watching a video of two life-size people in a dialog solving a Diapix task. The dialogue was directionally presented and together with background noise in the frontal hemisphere at 60 dB SPL. During three conditions of steering (none, in-ear EOG, conventional eye-tracking), participants' comprehension was periodically measured using multiple-choice questions. Based on eye movement detection by in-ear EOG or conventional eye-tracking, the estimated attended speaker was amplified by 6 dB. In the in-ear EOG condition, the estimate was based on one selected channel pair of electrodes out of 36 possible electrodes. A novel calibration procedure introducing three different metrics was used to select the measurement channel. The in-ear EOG attended speaker estimates were compared to those of the eye-tracker. Across participants, the mean accuracy of in-ear EOG estimation of the attended speaker was 68%, ranging from 50 to 89%. Based on offline simulation, it was established that higher scoring metrics obtained for a channel with the calibration procedure were significantly associated with better data quality. Results showed a statistically significant improvement in comprehension of about 10% in both steering conditions relative to the no-steering condition. Comprehension in the two steering conditions was not significantly different. Further, better comprehension obtained under the in-ear EOG condition was significantly correlated with more accurate estimation of the attended speaker. In conclusion, this study shows promising results in the use of in-ear EOG for visual attention estimation with potential for applicability in hearing assistive devices.

Keywords: EOG; audio-visual; eye-tracking; hearing impairment; in-ear EEG; speech comprehension.