SAVANNAH, GA—The Neurological Disorders Depression Inventory for Epilepsy (NDDI-E), a brief self-report questionnaire, effectively predicted scores on the clinician-rated Hamilton Rating Scale for Depression (HAM-D) in patients with temporal lobe epilepsy, reported Jennifer Duncan Davis, PhD, at the 19th Annual Meeting of the American Neuropsychiatric Association.
The researchers assessed 24 patients with temporal lobe epilepsy—of whom 10 were depressed—and 12 neurologically healthy patients with depression. Participants were administered the NDDI-E, the 17-item HAM-D, and the Mini International Neuropsychiatric Interview, and the pattern of symptom complaints on the NDDI-E and HAM-D among both groups of patients was observed.
The mean age of neurologically healthy patients with depression was 36.08, and the mean ages of patients with temporal lobe epilepsy were 39.90 and 45.07, respectively, for those with and without depression. Patients with a history of mental retardation, current substance abuse, bipolar disorder, or other neurologic conditions unrelated to the etiology of the seizure disorder were excluded. Neurologically healthy participants were recruited from the community, while patients with temporal lobe epilepsy were recruited from an outpatient epilepsy clinic and diagnosed by a neurologist.
“The NDDI-E predicts HAM-D performance with acceptable sensitivity and specificity for both patients with temporal lobe epilepsy and neurologically healthy people,” said Dr. Davis, Clinical Assistant Professor of Psychiatry at Warren Alpert Medical School, Brown University, and a clinical neuropsychologist in the Department of Psychiatry at Rhode Island Hospital, both in Providence. Among all patients with temporal lobe epilepsy, “the NDDI-E differentiated between diagnostic levels of depressive symptoms on the HAM-D with 100% sensitivity, 90.0% specificity, and a positive predictive value of 0.67. Sensitivity and specificity were similar between the depressed temporal lobe epilepsy and neurologically healthy groups. Overall severity of scores on the NDDI-E and HAM-D were also comparable between the two depressed groups. Depressed patients with temporal lobe epilepsy endorsed somatic symptoms and loss of interest in activities less frequently than the neurologically healthy participants.”
Anhedonia and somatic symptoms, which occurred less frequently in those with temporal lobe epilepsy and depression, were associated with frontal systems, suggesting that depression in temporal lobe epilepsy manifests from limbic structures rather than frontal pathways, she said.
“This study supports the use of the NDDI-E as a brief screening alternative for depression in epilepsy. The NDDI-E was also effective at predicting depressive symptoms in our nonneurologic group, increasing the measure’s generalizability,” concluded Dr. Davis.
—Debra Hughes