جستجوی مقالات مرتبط با کلیدواژه "visual evoked potential (vep)" در نشریات گروه "پزشکی"

Devic’s disease is a progressive disease with visual loss. This study was performed to compare the changes in visual evoked potential in Devis patients and healthy subjects attending to Basir clinic in 2013 and 2014. In this cross-sectional descriptive study, 25 Devic’s patients and 25 healthy subjects attending to Basir clinic in 2013 and 2014 were enrolled and their VEP results were determined and compared between two groups. Data analyses were performed using t- test. The mean (± standard deviation) voltages in case and control groups were 4.4±2.8 microvolt and 6.2±2.3 microvolt, respectively (P=0.023). The mean latency was 105.3±10.8 millisecond in case group and 95.6±8.8 millisecond in control group (P=0.001). Totally, according to the obtained results in this study and comparison with other studies it may be concluded that Devic’s disease would result in decreased voltage and increased latency in VEP of the patients.

Background &objections: Migraine is the second most common cause of headache in15% of women and 6% of men. Migraine headaches areperiodic and usually with unilateral and throbbing quality,and often accompanied by nausea, vomiting, phonophobia, photophobia and malaise. Approximately 15-20% of migraine attacks start with visual aura or other neurological symptoms. So far there isn’t accurate and practical diagnostic test for this patients and diagnosis is based on clinical features and other causes. The aim of this study was to investigate the role of visual evoked potential (VEP) in patients with common and classic migraines and t effects on the electrophysiology of visual system and understanding pathophysiology in neurological symptoms. In this study, 44 migraine patients, including 28 patients with common and 16 patients with classical migraines admitted to neurology private clinics from January to June 2013 in Alavi hospital of Ardabil city and16 healthy volunteers (control group) were used. Mean wave, P100 Latency and P100-N140 Amplitude were compared and determined between three groups. The mean latency of P100 migraine group was significantly higher than healthy people. Average P100-N140 amplitude of migraine group was fewer than the control group, and the mean P100-N140 amplitude was more common than classical group. Despite differences in results of VEP tests, VEP can be used as an adjuvant test in the diagnosis of migraine, as well as a confirmation for distinguishing common and classical migraine and can be used as a tool in determining the severity of migraine and/or a parameter for its electrophysiological effects. However, more detailed studies are needed in this area.

Comparison of the results of visual evoked potential (VEP) in time domain and frequency domain between multiple sclerosis (MS) suspected patients and normal indivisuals. Eleven MS suspected patients with normal visual findings and 20 normal individuals were tested by VEP. Results were compared between two groups. The time domain results showed no significant difference between the two groups. Results of the frequency domain showed that Fmod value in the MS group (4.11.4 Hz) was less than the value in normal subjects (7.92.8 Hz) but, the number of peaks in power spectrum in the MS group (3.80.9) was more than the value in normal subjects (1.50.3). (P<0.001) Decreased nerve conduction velocity, nerve impulse blockage, and refractory period increase in MS may cause low pass shift in frequency spectrum that may lead to Fmod decrease and increase the number of peaks in spectrum. These finding may be useful for early diagnosis of MS.