Abstracts

Rationale: It is widely known that psychiatric disorders, including depression, are common in patients with epilepsy. Prior studies have suggested that psychopathology prior to epilepsy surgery is associated with an increased risk of psychiatric problems post-surgery. One study found that a patient’s report of depression prior to epilepsy diagnosis increases the risk of medically intractable epilepsy after diagnosis. To our knowledge, no studies have examined whether measures of depression predict post-surgical seizure outcome. This study specifically examined whether measures of depression prior to surgery for intractable epilepsy were useful in predicting seizure freedom after surgery.Methods: Records from January 1, 1998 to May 1, 2013 at Allegheny General Hospital Epilepsy Center were used to identify patients being evaluated for epilepsy surgery. Engel Classifications were determined through out-patient chart review. “Good outcome” was defined as class 1 or 2 at two year follow up (i.e. seizure free or rare disabling seizures). All included patients underwent psychological interview and completed the MMPI-2. Patient reports of depression prior to first seizure, since first seizure, and at time of the pre-surgical evaluation were recorded. MMPI scale 2 (Depression) was considered elevated with t-scores greater than 65.Results: 37 patients underwent surgery for intractable epilepsy, had at least two years of follow up, had a psychological evaluation with diagnostic interview, and completed the MMPI-2. Of the 37 patients, 20 were female (54.1%), 33 had a lobectomy (89%), and 34 had either a temporal lobectomy or lesionectomy (91%). Reported depression prior to first seizure, since first seizure, or at time of pre-surgical psychological evaluation was not associated with a lower probability of a good outcome (see table 1). However, patients with MMPI scale 2 elevations were significantly less likely to have good outcomes compared to patients with scale 2 normal t-scores (see table 2).Conclusions: Elevations on MMPI scale 2, a standardized measure of depression symptoms, were associated with a significantly lower probability of a good seizure outcome at two years post-surgery. Our failure to find a relationship between information provided by patients during a clinical interview suggests the need for standardized measures of psychopathology. We believe this finding adds to the literature suggesting that depression symptoms may be a marker for brain pathology and have important implications for understanding, evaluating, and treating patients with epilepsy. This finding is also useful to clinicians counseling patients about the potential risks and benefits of proceeding with epilepsy surgery.