The registration of electrical activity of the human brain based on examining visual evoked potencial (VEPs) during a visual stimulation allows the evaluation of the quality of visual perception and the diagnose of eye disorders. Examination of VEPs is an objective method used worldwide for the diagnosis of neuro-ophthalmological and central nervous system diseases (e.g. Multiple Sclerosis, Optic Neuritis, Amblyopia, age related visual disorders, encephalopathies) but until now existing bulky and expensive devices for VEPs examination has only been used in specialised labs, which significantly limited deployment of this method. That is the reason why the Institute of Pathological Physiology of Charles University in Hradec Králové decided to develop and patent a low-cost, simple to use, 4-channel wearable device for examination of VEP. With the new device, it is now possible to carry out the diagnosis where needed, including at home, without the need for specialized personnel and at lower costs in comparison to the other market alternatives (around three times cheaper).
The new non-invasive wearable device developed consists of a visual stimulator (a matrix of light-emitting diodes with adjustable luminance and colour) which produces a large spectrum of monocular or binocular stimuli (including those with a cognitive task) and a recording part (based on a 4-channel electroencephalogram – EEG – amplifier).
The device is built into an ergonomic headset enabling positioning of the visual stimuli in various parts of the visual field. Two electrodes placed in the fixating belt of the headset record VEPs from the forehead and two additional recording electrodes can be freely located over the activated part of the brain cortex (according to the used variant of visual stimuli).
The recorded VEPs are transmitted via an USB port to a PC for display and off-line evaluation. The device is supplied with a sensor of the background luminance (influencing the LED stimulation luminance) and with a 3D accelerometer enabling elimination of artefacts caused by movements of subjects during examination.
Long term monitoring of VEPs is desirable for certain patients; with this device, it is possible for a long-term VEP monitoring (even during working activities). The device has unlimited mobility, can be used where needed (indoors, outdoors) and is easily handled, so it eliminates need for specialised staff. The home monitoring of VEP enables early detection of changes and hence possibly the prevention of critical brain disorders and provides objective information about changes in reactivity of the central system. Moreover, it is relatively simple and cheap when compared with the standard VEP equipment.
Since the device is essential for registration of electrical activity of the human brain during a visual stimulation, with examination of the visual evoked potentials, it is useful for all public and private health care facilities and neuro-ophthalmological sector. The device may be attractive also for bio-medical schools for demonstrations of brain functions and since it can also be used for evaluation of cognitive processes in the brain, it can help with assessment of psychiatric disorders and improve effectiveness of the therapy. Moreover, it can be used for early detection of fatigue and sleepiness in various professions, not only in the medical sector. Therefore, with its low cost, ease of wearing and easy handling features, it is suitable also for companies and institution.