Abstract
Aim: Visual evoked potentials (VEP) represent an objective non-invasive and inexpensive dia-gnostic method, particularly in neuro-ophthalmology. A lot of possible dia-gnostic applications are limited because they are only examined with the use of robust equipment which is hardly transportable and immobile and handicapped patients cannot visit the specialized labs.
The aim of our research work was the development of a portable inexpensive VEP device that could be used almost anywhere. Methods: All parts of the last prototype of the device (built-in visual stimulator, recording electrodes, 4-channel EEG amplifier, analog-digital converter, and control unit) with a total weight of 390 g are placed in a headset (plastic "shield" with an adjustable strap).
The software for VEP recording and evaluation is used on a standard notebook (PC). The parameters of the device fulfill recommendations of the international societies for clinical electrophysiology of vision and clinical neurophysiology also enabling new applications of so far not routinely used variants of evoked potentials.
Testing of the device was done so far in 91 control subjects and 135 neuroophthalmological patients. Results: Pilot studies proved comparable parameters of VEP and dia-gnostic sensitivity as in standard devices (equal results in 93% of cases).
It was verified that the device is usable in various environments, at the patient's bedside, and also for basic self-examination. Conclusion: The portable device for VEP significantly increases the availability of their examination and thus enables much broader dia-gnostic applications of this method.