EEG is usually abnormal in all of the following, except :

Answer is B (Locked in state): `Normal a- activity on the EEG in a patient of coma ales the clinician to the locked in syndrome or to hysteria or catatonia.' - Harrison 16th/1629 All conditions other than the 'locked in state' present characteristic EEG patterns. EEG Characteristic; Subacute sclerosing panencephalitis (SSPE) Creutzfoldt Jackob disease (CJD) Hepatic encephalopathy Characteristic periodic pattern with bursts Characteristic stereotype periodic bursts of < 200 Characteristic Symmetric every 3 to 8 seconds of high voltage, sharp ms duration occurring every I to 2 sec. Makes the high voltage triphasic slow slow waves followed by periods of attenuated diagnosis of CJD very likely wave infrontal region (falt) background (Repetitive high voltage, triphasic and polyphasic sharp discharges are seen in most advanced cases) Locked in state : This represents a pseudocoma in which an awake patient has no means of producing speech or volitional movement in order to indicate that he awake Patient may signal with veical eye movement and lid elevation which remain unimpaired. It usually results from infarction or haemorrhage of the ventral pons which transects all descending coicospinal and coicobulbar pathways. EEG is normal