Use of CT in epilepsy: does it matter how long you wait?

Computer tomography (CT) of the brain is of value for finding potentially correctable lesions in adult patients with new onset seizures. The value of CT is unknown, however, for finding such lesions in adult chronic epileptic patients without prior CT. We compared a group of 177 adult patients who had CT within a year from the onset of seizures to a group of 93 patients who had a history of seizures for more than a year before CT was performed. In the first group, 33 potentially correctable lesions (19%) were found including 17 tumors. The group with chronic epilepsy had 4 (4%) potentially correctable lesions: 3 arteriovenous malformations and 1 meningioma. It seems that CT is of value in discovering potentially removable lesions in chronic epileptic patients, but the likelihood is relatively small. The incidence of stable structural lesions seems to be similar in the two groups.     

Alternatives to lithium in the treatment of bipolar disorder.

Bipolar disorder is a serious mental illness affecting a large number of Americans. While lithium, the treatment of choice for this disorder, is usually effective, a substantial number of individuals with bipolar disorder are not helped by lithium or are intolerant to its side effects. Consequently, investigators are searching for alternative drugs in order to treat lithium-resistant patients. Although a number of alternative drug treatments have been discussed in the literature, only the anticonvulsants carbamazepine and valproate appear to warrant serious consideration at this time. Future research will further define their roles as antimanic agents.     

Test-retest reliability in EEG frequency analysis.

This study was performed to gain a better understanding of EEG frequency analysis test-retest reliability in normal healthy adults, and to evaluate factors which could influence the measured inter-record differences. Nineteen subjects underwent serial EEG recordings at 5 min and 12-16 week intervals. Records were visually edited using a standardized protocol, and FFT frequency analysis performed on segments of 60, 40, or 20 sec total length. Correlation coefficients for broad band features averaged 0.92 over the 5 min retest interval and 0.84 over the 12-16 week interval. There was essentially no difference between correlation coefficients of absolute and relative power features. Coefficients based on 60 sec records were marginally higher than those of 40 or 20 sec records. On the other hand, test-retest percent differences were typically lower for relative as opposed to absolute power features, and 60 sec records showed consistently lower percent differences than did 40 or particularly 20 sec records. Peak alpha frequency and mean frequency were the most stable EEG features at either interval. Montage had significant effects on test-retest differences at the 12-16 week interval. A significant association between intra-record and inter-record variability could not be demonstrated.