Visual Processing During the Interictal Period Between Migraines: A Meta-Analysis

Migraine is a poorly understood neurological disorder and a leading cause of disability in young adults. Migraines are characterized by severe pulsating unilateral headache and visual symptoms. Whether visual function is also impaired in the interictal period between migraines remains controversial. Thus, this meta-analysis investigated the evidence for altered visual function as measured electrophysiologically via pattern-reversal visual evoked potential (VEP) amplitudes and habituation in adult migraineurs with or without visual aura and control in the interictal period. Twenty-three studies were selected for random effects meta-analysis, demonstrating slightly diminished VEP amplitudes and substantially reduced habituation in the early P100 component in migraineurs without aura and with aura compared to controls. No differences were found between migraineurs with and without aura. Although heterogeneity between studies and insufficient published data for VEP latencies and the earlier N75 VEP component data was observed and require further testing, P100 anomalies may indicate abnormal functioning of the fast-conducting magnocellular visual pathway, in episodic migraineurs.

Facial Emotions Perceptions in Young Female Students with High- Level Anxity and Subclinical Panic Disorder. ERP and BEhavioral Study

ABSRACTThis study investigated facial emotion processing in non-medicated young students (girls) with panic disorder. 13 young girls with panic disorder and 14 matched healthy controls were recruited. Evoked potential (EP) components P100, N150, and P300 in the posterior areas, and N200, P300, and late negativity were evaluated while the participants recognize angry, fearful, happy, and neutral facial stimuli. The girls with panic disorder showed increased levels of situational anxiety compared to healthy controls. EP demonstrated an increased reactivity to facial expression at sensory stage (P100 component), in particular, on angry faces, that indicates a shift automated attention on threat facial stimuli. The increased reactivity was also found in later processing, corresponding to the P300 component, reflecting an enhanced selective attention to socially important events. In subjects with panic disorder, we also found signs of increased activation in the right temporal area in the P300 time window, and the increased late frontal negativity in 350-450 ms time window. It can be assumed, that altered functional state of the prefrontal regions results in reduced top-down modulating effects on the lower limbic and sensory cortex levels.

Analysis of the Relationship Between Training Experience and Visual Sensory Functions in Athletes from Different Sports

Introduction. Gaining insight into the mechanisms and scope of possible adaptations of visual functions to the conditions determined by the demands imposed by sports training seems to be very interesting not only from a cognitive point of view, but also with respect to the practical applications of the findings of such investigations in the training process. The aim of the study was to assess the function of early visual processing in athletes representing different sports disciplines with varying training experience. Material and methods. The study involved 95 athletes practising football (n = 24), volleyball (n = 22), boxing (n = 26), and rowing (n = 23). The bioelectric function of the visual pathway was assessed based on recordings of visual evoked potentials (VEPs). The regions which were stimulated were the peripheral and central areas of the retina. During the test, we recorded the amplitude (μV) and latency (ms) of the P100 component of the VEP waveform for both monocular stimulation (for the dominant and non-dominant eye) and binocular stimulation. Results. Lower VEP P100 amplitude values were found for the peripheral and central locations for monocular and binocular viewing in more experienced volleyball players and rowers (p < 0.05). In the case of boxers with greater training experience, a significantly lower (p < 0.05) amplitude of the VEP P100 wave was observed in the central location in the dominant eye. However, we did not find significant differences (p > 0.05) in intragroup variability in VEP P100 latency in relation to training experience in any of the sports disciplines examined. Conclusions. Training experience has an influence on the early stage of sensory processing with respect to neural activity. Training experience has been found to differentiate athletes in terms of the temporal parameters of the visual evoked potentials recorded in the current study only to a limited extent.

Visual evoked potentials in diagnostics of optic neuropathy associated with renal failure

Chronic renal failure is associated with many neurological complications. Due to accumulation of uremic neurotoxins axonal degeneration with its secondary demyelination occurs, which results in development of polineuropathy in 60-100% of patients with chronic renal failure. One of the most severe peripheral neuropathy is optic neuropathy. It is associated with visual deterioration and reduction in quality of life. Symptoms of the optic neuropathy may appear either before or after dialysis therapy. They often worsen after renal transplant, probably due to immunosuppressive regimen. Early diagnostics of the optic neuropathy became possible by using visual evoked potentials (VEP). This reliable, sensitive and noninvasive technique provides a direct measure of subclinical impairment of visual pathways. Among hemodialysed or immunosupressed patients one can observe abnormal VEP parameters – especially prolonged latency of the P100 component, less often fluctuation of its amplitude. These alterations are pronounced even if clinical examination reveals no abnormalities. This review presents a summary of current use of visual evoked potentials in monitoring of patients with chronic renal failure.

DIAGNOSTIC OPPORTUNITIES OF NEUROOPHTHALMOLOGIC INSPECTION AT RS: ROLE OF AN OPTICAL COHERENT TOMOGRAPHY AND THE VISUAL CAUSED POTENTIALS IN EARLY DIAGNOSTICS OF MULTIPLE SCLEROSIS AND MONITORING OF A CONDITION OF THE VISUAL ANALYZER AT PATIENTS WITH VARIOUS OPTIONS OF MULTIPLE SCLEROSIS

Examination of 70 patients with different options of a course of multiple sclerosis is conducted. Reliable decrease in thickness of a layer of a neuroepithelium and macular volume of a retina at patients with various options of a course of the multiple sclerosis, more expressed is noted at primary progressing and secondary progressing current options, and the patients who have transferred an optical neuritis. The functional violations at the level of an optic nerve according to the visual caused potentials – increase in a latence and decrease in amplitude of the P100 component are revealed. Possibility of application of methods of an optical coherent tomography and the visual caused potentials for diagnostics and monitoring of pathological process is shown at multiple sclerosis.

The effects of bromazepam on the early stage of visual information processing (P100)

The early stages of visual information processing, involving the detection and perception of simple visual stimuli, have been demonstrated to be sensitive to psychotropic agents. The present study investigated the effects of an acute dose of bromazepam (3 mg), compared with placebo, on the P100 component of the visual evoked potential and reaction time. The sample, consisting of 14 healthy subjects (6 male and 8 female), was submitted to a visual discrimination task, which employed the "oddball" paradigm. Results suggest that bromazepam (3 mg) impairs the initial stage of visual information processing, as observed by an increase in P100 latency.