Characterization of the cerebral visual electrophysiology response of healthy subjects using portable and low-cost electroencephalography

Abstract

ABSTRACT: A set of stimuli to perform visual cortex activation covering most of the visual skills was developed. As a result, six stimuli were designed, each of these with editable parameters for other tests. This set presents 3 previously reported stimuli and 3 exploratory stimuli. The stimuli were designed for activating different visual function: acuity, contrast sensitivity, visual field, motion perception, form recognition, and color detection. These stimuli were presented to 37 healthy control subjects. During the whole experiment, subjects were seated in a comfortable chair in a slightly dimmed room about 1 m in front of the stimulation unit. Different stimuli were showed and analyzed to identify which have the most significant difference in power spectrum and coherence measures. In the first part an exploratory analysis was performed to identify outliers, initial trends and frequency response for the acuity and contrast stimuli. Also, statistical analyses were conducted, such as repeated measures ANOVA. Our results indicated that relative delta, theta and alpha power could be an indicator to distinguish between eyes open and eyes closed while specific power bands can give information for stimulation stages. Similarly, coherence analysis allowed us to find sensibility factors for each stage. With these stimuli and baseline in some measures characteristic of each one will be possible to compare these variables in patient with neuro-ophthalmological disorders and in neurological rehabilitation using the proposed stimuli to activate the different visual functions.