Detecting Preperimetric Glaucoma with the nGoggle, a Portable Brain-Computer Interface for Assessing Neural Damage

Abstract

Purpose : This study investigated the feasibility and efficacy of the nGoggle (nGoggle, Inc., San Diego, CA.), which is a portable brain-computer interface for objective assessment of visual function loss, to diagnose functional damages in eyes with preperimetric glaucoma (PPG).

Methods : We included 30 eyes of 20 patients with PPG and 18 eyes of 11 healthy patients tested with the nGoggle, standard automated perimetry (SAP SITA 24-2) and spectral domain optical coherence tomography (SDOCT) within 3 months. Eyes with PPG had evidence of glaucomatous optic neuropathy on optic disc stereophotographs but normal visual field results on SAP. The nGoggle is a portable device that integrates wearable, wireless, dry electroencephalogram systems and a head-mounted display, allowing detection of multifocal steady-state visual evoked potentials (mfSSVEP) associated with visual field stimulation. Visual stimuli eliciting mfSSVEPs in 20 sectors over the 35° field of vision were presented on the nGoggle’s display. The metrics of mfSSVEPs for all sectors were computed by canonical correlation analysis (CCA). A global CCA metric was calculated as the average of values for each sector. Receiver operating characteristic (ROC) curves were used to compare diagnostic accuracy.

Results : Mean age was 68.7±10.3 years in PPG group and 65.1±10.5 years in control group (P=0.363). As expected, there were no significant differences in SAP 24-2 MD (-0.1±1.4 dB vs. 0.6±1.2 dB; P=0.092) and PSD (1.6±0.3 dB vs. 1.5±0.2 dB; P=0.481) between groups. There was a significant difference in SDOCT average retinal nerve fiber layer (RNFL) thickness between groups (81.7±11.4 μm vs. 98.4±10.5 μm; P<0.001). The nGoggle mfSSVEP parameter also showed a statistically significant difference between groups (0.291±0.021 vs. 0.334±0.028; P<0.001). The area under the ROC curve (AUC) for the nGoggle summary parameter was 0.896 (95% CI: 0.801-0.984), which was comparable to the AUC of 0.879 (95% CI: 0.785-0.972) found for SDOCT average RFNL thickness (P=0.800).

Conclusions : The nGoggle was able to discriminate eyes with PPG from healthy eyes, with a performance comparable to SDOCT, suggesting it is capable of early detection of glaucoma damage.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

A subject with the nGoggle.

 

Receiver operating characteristic curves for nGoggle summary parameter and spectral domain optical coherence tomography (SDOCT) retinal nerve fiber layer (RNFL) thickness.