Pattern reversal visual evoked potentials (PVEPs) in transient ischemic attacks (TIAs) and prolonged reversible ischemic neurological deficits (PRINDs) of anterior circulation with normal EEGs and normal cranial CTs

Out of 75 patients with TIA or PRIND we selected 9 TIAs and 6 PRINDs with normal EEGs and CCTs, full recovery of neurological function, no history of amaurosis fugax and no findings of visual impairments. PVEPs were derived from 01-02 to Fz and Cz as ground following binocular pattern reversal visual stimuli of 1.9 Hz. Interhemispheric differences of the latencies of P60, N80, P100 and of the amplitudes N80/P100 and P100/N140 were compared with the corresponding parameters of 22 age matched controls. In contrary to the latency differences the interhemispheric difference of the amplitude N80/P100 was highly significantly larger (33.5 +/- 16.0%) in patients than in the control group (12.8 +/- 9.8%) (por = .0005). The amplitude P100/N140 behaved the same way (por = .025); the amplitude of the affected side being smaller. There were no statistical differences between TIAs and PRINDs and a tendency was seen for normalization of the differences with increasing time distances between the onset of the ischemic attack and the point of time of the recordings.