The value of clinical, EEG, and MRI findings in the diagnosis of specific epilepsy syndromes following a first unprovoked seizure was evaluated in 300 consecutive patients, including 59 children, aged 5-16 yrs (20%), studied prospectively at the Austin Medical Centre, Heidelberg, Melbourne, Australia. A clinical diagnosis of generalized or partial epilepsy was made in 141 (47%) cases, without reference to subsequent EEG or MRI findings. EEG data, especially when obtained within 24 hrs, increased the number diagnosed to 232 (77%). The addition of MRI data provided a prompt and final diagnosis of generalized or partial epilepsy in 243 (81%) patients. The final diagnoses were generalized epilepsy in 23%, partial epilepsy (58%), and unclassified (19%). Benign rolandic epilepsy and benign occipital epilepsy were diagnosed in 13 children (22% of the children). Temporal lobe epilepsy accounted for 57% of partial epilepsies. MRI was important in early diagnosis, except for children with benign rolandic epilepsy and patients with idiopathic generalized epilepsies. [1]

COMMENT. In children 5 years of age and older and in adults, clinical, EEG, and MRI data permit early diagnosis and differentiation of partial and generalized epileptic syndromes in 81% of patients who present with a first seizure. Clinical examination should include a careful history of possible previous non-convulsive seizures, often overlooked and occurring in 28% of the Melbourne study group. EEG should be obtained early, ideally within 24 hrs of the seizure. MRI aids in diagnosis, except in idiopathic generalized epilepsy, confirmed by EEG, and benign rolandic epilepsy. MRI is superior to CT in the diagnosis of brain tumors; CT with contrast missed 1 angioma and 8 surgically remediable tumors, including 4 astrocytomas.

Quantitative MRI in patients with idiopathic generalized epilepsy demonstrated subtle, but widespread, cerebral structural changes (focal cerebral dysgenesis) not identified on routine MRI in a study at the Institute of Neurology, London, UK. [2]