Paper- and online-based externally validated nomograms are effective in predicting naming decline after temporal lobe surgery in patients with epilepsy, according to study results published in Neurology. Factors predictive of postsurgical naming decline in this patient population included side of surgery, age at epilepsy onset, age at surgery, sex, and education, and preoperative naming score.
A total of 719 patients with epilepsy who underwent temporal lobe epilepsy surgery at the Cleveland Clinic were included in the study. In addition, the investigators enrolled an external validation cohort of 138 patients who also underwent temporal lobe surgery at Columbia University Medical Center, Emory University School of Medicine, or University of Washington School of Medicine.
Researchers used the 60-item Boston Naming Test to assess 6- to 12-month postsurgical naming outcome. Candidate predictors for model development included sex, education, age at surgery, age at epilepsy onset, duration of epilepsy, side of surgery (dominant or nondominant), presence or absence of hippocampal sclerosis on preoperative magnetic resonance imaging, lesional or nonlesional preoperative magnetic resonance imaging, hippocampal resection (resected or spared), and baseline Boston Naming Test raw score.
Approximately 26% of participants (n=187) in the main cohort and 30% (n=41) in the validation cohort experienced clinically relevant naming decline after temporal lobe surgery. In an analysis adjusted for covariates, dominant-side resection was associated with a 14 times greater odds of naming decline (odds ratio 14.07; 95% CI, 8.48-23.34; P <.001). In addition, for each year older a patient was at the time of epilepsy onset, there was a 5% increased odds of naming decline (odds ratio 1.05; 95% CI, 1.03-1.07; P <.001).
The 5-variable model comprised of side of surgery, age at epilepsy onset, age at surgery, sex, and education performed well in the external validation cohort and featured a c statistic of 0.81. In the second model, which included 3 predictor variables (side of surgery, age at epilepsy onset, and preoperative naming score), the model featured a c statistic of 0.84 and demonstrated good calibration.
Limitations of the study were the inclusion of patients who only underwent temporal lobe surgery and the inclusion of only patients with epilepsy who underwent surgery at a single specialized center.
“We view these models as an important first step toward the development of a set of comprehensive, well-validated tools for predicting neurobehavioral outcomes following epilepsy surgery,” the researchers concluded. “The use of such tools will improve preoperative decision-making and patient counseling as well as increase clinician confidence in their preoperative risk assessment.”
Busch RM, Hogue O, Kattan MW, et al. Nomograms to predict naming decline after temporal lobe surgery in adults with epilepsy. Neurology. 2018;91(23):e2144-e2152.