Focal epilepsy: electroencephalogram (EEG) showing focal epileptic spikes over the left mid- temporal region of the brain. The EEG records electrical activity within the brain through a series of electrodes taped over the subject's head. The traces (numbered 1-16) refer to locations over the brain as indicated on the diagrams at left. The epileptic spikes are most apparent on trace 14 (less so on 13 & 15) and trace 6. Focal or symptomatic epilepsy is a symptom of organic brain disease; location determines the nature of the fit or symptoms. Epilepsy is a general term for recurrent losses of brain function that are sudden in onset.