Time course of focal slow wave activity in transient ischemic attacks and transient global amnesia as measured by magnetoencephalography

In this longitudinal study multichannel MEG was used to localize and to qua ntify focal pathological spontaneous neuromagnetic activity in six patients with transient ischemic attacks (TIA) and two patients with transient glob al amnesia (TGA). Slow (2-6 Hz) and beta (14-30 Hz) activity were monitored up to 10 weeks. Results were compared with normative data, and changes ove r time were statistically analyzed. MEG detected pathological activity that persisted clinical symptoms. Focal slow activity originating from sensorim otor (TIA) and mesiotemporal (TGA) cortices exceeded normal values up to 14 times during the first hours after the attack and recovered to normal with in I I days. Focal beta activity was not useful to monitor the time course of TIA or TGA. NeuroReport 11:3309-3313 (C) 2000 Lippincott Williams & Wilk ins.