[Smooth pursuit in migraine patients]

Neurotologic signs and symptoms, especially vestibular symptoms, are common in migraine patients. The goal of this study was to investigate some parts of the central vestibular system using some subtests of videonystagmographic evaluation, including spontaneous nystagmus, gaze-evoked nystagmus, and smooth pursuit between their attacks of migraine. Thirty patients with migraine and 38 healthy volunteers of 18-48 years of age were included in this study. Spontaneous nystagmus, gaze-evoked nystagmus toward the right, left and upward, and also smooth pursuit using three different velocities were performed in both groups. Five normal subjects and five migraine patients had spontaneous nystagmus, which was less than three degrees; there was no statistically significant difference between the two groups. No gazeevoked nystagmus was seen in both groups. In one velocity of smooth pursuit evaluation, gain and phase were significantly different. The statistical difference in gain and phase was not clinically important as it was in normal range of the device. Another statistically significant parameter was saccadic morphology of smooth pursuit which was seen in migraine patients. These results suggest the presence of subtle otoneurological abnormalities in migraine patients that is probably due to deficiency of oculomotor function with vestibulocerebellar origin

[Comparison of cognitive potential P300 with high and low frequency stimulus in early onset blind subjects]

Previous studies suggest that auditory stimulus frequency in normal subjects contribute to both P300 amplitude and latency measures. As occipital cortex devotes to other modalities including auditory inputs, the purpose of this study was to determine the effects of stimulus frequency in early blind subjects. Fifteen early blind subjects [8 males and 7 females] with mean age of 25.13 +/- 4.27 years were tested. Cognitive potential P300 was recorded in response to high [1000/2000Hz] and low [250/500 Hz] frequencies auditory stimuli using an oddball task in 70 dB nHL. While participants answered to target stimulus, amplitude and latency of P300 was recorded. With high frequency stimuli, mean amplitude in early onset blind subjects obtained 14.13 +/- 5.53 micro v and was 17.59 +/- 8.17 micro v with low frequency. With high and low frequency, mean latency of P300 obtained 295.60 +/- 31.33 ms and 317.38 +/- 21.71 ms respectively. Comparison of results between two stimuli showed that there were statistically significant differences between amplitudes [p=0.008] and latencies [p=0.001] of cognitive potential P300. Changing low frequency to high frequency results in decreasing both amplitude and latency. It seems that auditory stimuli frequency affect the P300 parameters in blind subjects