EEG is a test of cerebral function, it indicates any generalized or focal dysfunction of brain.  Generalized slowing of EEG waves is seen in diffuse encephalopathies.  It helps in differentiating in epileptiform encephalopathies and epilepsy conditions.
Encephalopathy electroencephalogram
Anoxic brain injury electroencephalogram
Myxedema coma laboratory findings
Seizure other imaging findings
Encephalopathy echocardiography or ultrasound
Wernicke-Korsakoff syndrome MRI
Encephalopathy other imaging findings
Encephalopathy MRI