Source: Neurology  |  Posted 9 years ago

Resection of the left temporal lobe for the treatment of epilepsy is associated with a decline in verbal memory that continues over several years. Such declines may impact on patients' quality of life.

R. Rausch from the departments of neurology and psychiatry and biobehavioral sciences and colleagues from the University of California, Los Angeles, United States, set out to evaluate cognitive changes that adult patients experience following standardised temporal lobe resection for control of intractable complex partial seizures. They also looked at the link between quality of life, seizure control and verbal memory skills over the long term.

As part of a longitudinal study, 44 patients with intractable epilepsy completed cognitive testing prior to undergoing epilepsy surgery. All the patients underwent an en bloc left or right temporal lobe resection, and the findings with these surgical patients were compared with those of eight patients with epilepsy who did not undergo surgery and served as controls.

Patients who underwent left temporal lobe resection had selective early decreases in verbal memory. During a mean follow-up period of 12.8 years (at least 9 in all patients), this early decrease worsened. All three groups experienced declines in visual memory over time. In general, results of cognitive testing not relating to memory remained stable over time.

Undergoing left temporal lobe surgery and having high scores prior to surgery were both predictors of decreases in verbal memory at early follow-up. Higher scores at one year predicted increased late memory decline. Having left temporal lobe surgery also predicted late decline in verbal memory that was sensitive to the integrity of the left hippocampus.

Quality of life scores were superior among patients who had better seizure control and who had a higher everyday verbal memory skill, specifically, prose recall.

Based on these findings, the authors concluded that verbal memory deficits are more likely to follow left temporal lobe epilepsy surgery, which may continue over the long term. Late declines in multiple memory scores were seen in epilepsy patients regardless of whether they underwent surgery, which may be a factor of aging. Thus, patients who undergo left temporal lobe surgery may be at higher risk for a faster drop in selective verbal memory skills, which could impact on quality of life. This should be taken into consideration when deciding to perform epilepsy surgery in this area.