The role of cerebral lesions associated with absence seizures, outside the frontal lobe, has not been demonstrated by both electroencephalography and neuroimaging techniques until now, to our knowledge. We present a case with absence seizures and EEGs with generalized 3 Hz spike-wave patterns that were preceded by a burst of spike-waves on the right parieto-occipital region. The patient had a history of head trauma, and cranial MRI revealed lesions that might be responsible for the seizures. The patient's lateralized and localized EEG findings were probably a representation of secondary bilateral synchrony (SBS). The mechanism of SBS is considerably more complex than a simple triggering of generalized spike-wave complexes from a single cortical focus.