Focal injuries in the intracranial space can lead to abnormal EEG patterns and epileptogenic activity in the brain resulting in convulsive and nonconvulsive seizures (NCS). Abnormal EEG changes consist of slowing of the physiological rhythms, reduction of the higher frequencies in the alpha and beta ranges, and increase in the delta frequency activity. Epileptogenic EEG changes span a range of activities including focal sharp waves, spikes, polyspikes, and evolving ictal activity, which occur in the form of rhythmic discharges. Also, in between these patterns frequently there can be an ictal-interictal continuum (IIC) consisting of periodic discharges (PDs) or rhythmic delta activity (RDA), which can be lateralized or generalized in distribution. The epileptiform discharges (spikes, sharp waves) can be either focal or broad based with unclear localization. As the epileptiform discharges become more frequent or evolve into seizures, the patients may present with a change in mental status. The seizures can be either convulsive or nonconvulsive in nature. The seizures with clinical manifestations, especially obvious features of convulsions, are usually diagnosed earlier than the nonconvulsive seizures. NCS can present with subtle clinical features and may be missed early on, and in some situations, the diagnosis is made only based on EEG monitoring. This is especially relevant in cases of lesions involving the non-motor cortex, where the clinical features are not obvious and diagnosis may be missed.