Contribution of Neuropsychological Data to the Prediction of Temporal Lobe Epilepsy Surgery Outcome

Abstract

Summary: Purpose:We empirically examined the contribution of' neuropsychological data to the prediction of postoperative seizure control relative to base rate information in an existing series of patients undergoing anterior temporal lobectomy (ATL).Methods: A discriminant function predicting surgery outcome (seizure-free vs. non-seizure-free) was computed separately for samples of patients with left (n = 79) and right (n = 62) temporal lobectomy (LATL, RATL). Predictor variables included 14 measures tapping five neurocognitive domains. The predicted base rates were compared with the actual base rates in the two samples. Finally, overall predictive accuracy was examined in optimal versus suboptimal ATL patients.Results: The base rate of seizure freedom in the LATL group was 74.70%; that in the RATL group was 66.10%. The predictive function for the LATL group achieved a hit rate of 80.00% and a positive predictive power of 92.1 1%. The function for the RATL group achieved a hit rate of 83.33% and a positive predictive power (PPP) of 89.66%. The overall predictive accuracy for the optimal group was only 55%, but that in the suboptimal group was 72%.Conclusions: Neuropsychological data used in a multivariate statistical fashion may be able to offer an incremental increase in the prediction of postoperative seizure freedom relative to existing base rates of surgery success in patients with ATL epilepsy. The use of neuropsychological data may be of greatest predictive value in a population of ATL candidates with suboptimal findings with a lower base rate of postoperative seizure freedom, but may actually reduce predictive accuracy in a group of ATL candidates from an optimal population with an already high base rate of surgical success.

Clinical utility of the Wechsler Memory Scale—Fourth Edition (WMS-IV) in predicting laterality of temporal lobe epilepsy among surgical candidates

“…The potential value of the WMS-IV measures to predict seizure freedom for patients with localization-related epilepsies, particularly among those individuals who are MRI negative for abnormalities, also should be investigated [10,[34][35][36]. Additionally, WMS-IV studies with concurrent functional imaging data among both healthy samples and samples with TLE could explore the neural substrates involved in performance on the WMS-IV memory subtests.…”

The Little Black Book of Neuropsychology

“…(b) Predicting seizure freedom. Although limited to select cases, emerging studies have shown neuropsychological data can add unique variance in predicting likelihood a patient will be seizure-free after surgical treatment (e.g., Helmstaedter and Kockelmann 2006;Keary et al 2007;Potter et al 2009;Sawrie et al 1998;Seidenberg et al 1998). Often the additive predictive value is demonstrated for individuals with normal neuroimaging (i.e., nonlesional) or incongruent ictal and inter-ictal EEG findings, and generally have not included multiple non-invasive studies in addition to neuropsychological data (e.g., MEG/MSI, fMRI, PET, SISCOM studies).…”

“…Often the additive predictive value is demonstrated for individuals with normal neuroimaging (i.e., nonlesional) or incongruent ictal and inter-ictal EEG findings, and generally have not included multiple non-invasive studies in addition to neuropsychological data (e.g., MEG/MSI, fMRI, PET, SISCOM studies). A recent study combining multiple predictors did not find that neuropsychological data added unique variance (Bell et al 2009 (Akunama et al 2003;Helmstaeder 2004;Hennessy et al 2001;Keary et al 2007;Potter et al 2009;Rausch 2006;Sawrie et al 1998). Alternatively, neuropsychological data have clear utility to evaluate the functional adequacy of mesial temporal lobes and other cerebral areas (e.g., Baxendale and Thompson 2010;Chelune 1995;Seidenberg et al 1998;Stroup et al 2003).…”

“…Recent data suggest neurological and demographic variables provide the best predictors of being seizure-free (unilateral EEG abnormalities, single pathology of mesial temporal sclerosis, duration of seizures, age of seizure onset). Neuropsychological variables have shown less predictive value, but significant variance to lateralizing seizure onset or predict seizure outcome has been demonstrated in some cases (e.g., Hennessy et al 2001;Helmstaedter and Kockelmann 2006;Keary et al 2007;Sawrie et al 1998;Seidenberg et al 1998). In addition, it is important for the neuropsychologist to provide input to the epilepsy surgery program regarding the potential neuropsychological risks with surgery.…”

“…Neuropsychological variables predicting seizure remission: Evidence-based Neuropsychology: In general, neuropsychological data are not helpful in predicting seizure outcome. However, some studies have shown neuropsychological data incrementally improves prediction of seizure freedom (Hennessy et al 2001;Potter et al 2009;Sawrie et al 1998). Hennessy et al (2001) found impaired verbal memory was associated with better seizure-free outcome for patients having a left temporal lobectomy.…”