A Single-Channel and Non-Invasive Wearable Brain-Computer Interface for Industry and Healthcare

Summary

This paper discusses how to build a brain-computer interface by relying on consumer-grade equipment and steady-state visually evoked potentials. For this, a single-channel electroencephalograph exploiting dry electrodes was integrated with augmented reality glasses for stimuli presentation and output data visualization. The final system was non-invasive, wearable, and portable.

Abstract

The present work focuses on how to build a wearable brain-computer interface (BCI). BCIs are a novel means of human-computer interaction that relies on direct measurements of brain signals to assist both people with disabilities and those who are able-bodied. Application examples include robotic control, industrial inspection, and neurorehabilitation. Notably, recent studies have shown that steady-state visually evoked potentials (SSVEPs) are particularly suited for communication and control applications, and efforts are currently being made to bring BCI technology into daily life. To achieve this aim, the final system must rely on wearable, portable, and low-cost instrumentation. In exploiting SSVEPs, a flickering visual stimulus with fixed frequencies is required. Thus, in considering daily-life constraints, the possibility to provide visual stimuli by means of smart glasses was explored in this study. Moreover, to detect the elicited potentials, a commercial device for electroencephalography (EEG) was considered. This consists of a single differential channel with dry electrodes (no conductive gel), thus achieving the utmost wearability and portability. In such a BCI, the user can interact with the smart glasses by merely staring at icons appearing on the display. Upon this simple principle, a user-friendly, low-cost BCI was built by integrating extended reality (XR) glasses with a commercially available EEG device. The functionality of this wearable XR-BCI was examined with an experimental campaign involving 20 subjects. The classification accuracy was between 80%-95% on average depending on the stimulation time. Given these results, the system can be used as a human-machine interface for industrial inspection but also for rehabilitation in ADHD and autism.

Introduction

A brain-computer interface (BCI) is a system allowing communication with and/or control of devices without natural neural pathways¹. BCI technology is the closest thing that humanity has to controlling objects with the power of the mind. From a technical point of view, the system operation works by measuring induced or evoked brain activity, which could either be involuntarily or voluntarily generated from the subject². Historically, research focused on aiding people with motor disabilities through BCI³, but a growing number of companies today offer BCI-based instrumentation for gaming

Protocol

The study was approved by the Ethical Committee of Psychological Research of the Department of Humanities of the University of Naples Federico II. The volunteers signed informed consent before participating in the experiments.

1. Preparing the non-invasive wearable brain - computer interface

1. Obtain a low-cost consumer-grade electroencephalograph with dry electrodes, and configure it for single-channel usage.
   1. Short-circuit or connect any unused input cha.......

Discussion

The proper functioning of the system involves two crucial aspects: SSVEP elicitation and signal acquisition. Aside from the specific devices chosen for the current study, SSVEP could be elicited with different devices providing a flickering light, though smart glasses are preferred to ensure wearability and portability. Analogously, further commercial electroencephalographs could be considered, but they would have to be wearable, portable, and involve a minimum number of dry electrodes to be user-friendly. Moreover, the .......

Materials

Name	Company	Catalog Number	Comments
Conductive rubber with Ag/AgCl coating	ab medica s.p.a.	N/A	Alternative electrodes – type 2
Earclip electrode	OpenBCI	N/A	Ear clip
EEG-AE	Olimex	N/A	Active electrodes
EEG-PE	Olimex	N/A	Passive electrode
EEG-SMT	Olimex	N/A	Low-cost electroencephalograph
Moverio BT-200	Epson	N/A	Smart glasses
Snap electrodes	OpenBCI	N/A	Alternative electrodes – type 1