Whether brain surgery is likely to improve or worsen memory in a patient with epilepsy can be predicted before the operation is performed, according to findings in the journal Neurology.

Brain surgery can be very effective for some patients whose seizures do not respond to antiepileptic drugs, “but it is a procedure that is often associated with risks to memory,” lead author Dr. Sallie Baxendale noted in comments to Reuters Health.

“While memory problems are an important consideration in epilepsy surgery, it was also clear from our clinical experience of offering epilepsy surgery over the past 20 years at our center that postoperative memory improvements can also sometimes occur for a minority of patients.”

Baxendale, of the Institute of Neurology, London, UK, and colleagues examined the pre-operative characteristics of 237 patients who had a significant improvement in thinking ability following epilepsy surgery.

In patients who underwent surgery on the right side of the brain, a shorter duration of epilepsy, difficulty in learning verbal information, and a strong ability to learn visual information predicted that memory would improve after surgery.

With surgery on the left side of the brain, a shorter duration of epilepsy, difficulty in learning visual information, and a higher IQ predicted improved memory after surgery.

Epilepsy surgery “is not undertaken lightly by patients or physicians,” Baxendale told Reuters Health. “It is a sobering reflection of the burden of living with uncontrolled seizures that people consider it at all.”

“Based on the many hundreds of patients who have previously undergone the procedure, patients can now be given evidence-based odds on their chances of being rendered seizure free, in both the short term and the long term, and should be helped to weigh this up against the possible changes in cognitive function,” she continued.

“For some patients, epilepsy surgery may represent a win-win situation resulting in a cessation of seizures and an improvement in memory function,” Baxendale said. “This paper goes some way toward enabling us to identify this subgroup prior to surgery.”

SOURCE: Neurology, October 21, 2008.