Use of fMRI Language Lateralization for Quantitative Prediction of Naming and Verbal Memory Outcome in Left Temporal Lobe Epilepsy Surgery

Abstract

Partial removal of the anterior temporal lobe (ATL) is the most commonly performed surgical procedure for intractable epilepsy. AT L resection is highly effective for seizure control, resulting in long-term cure rates of 60–80% (McIntosh et al. 2001; Jeong et al. 2005;. Tellez-Zenteno et al. 2005). The undeniable benefit of AT L surgery is partially offset by the occurrence of neuropsychological morbidity in some patients receiving this treatment. Evidence suggests a 30–60% incidence of anomic aphasia (Hermann et al. 1994 Hermann et al. 1999a; Hermann et al. 1999b; Langfitt and Rausch 1996; Bell et al. 2000b; Sabsevitz et al. 2003) and a similar risk for decline in verbal memory ability (Chelune et al. 1993; Helmstaedter and Elger 1996; Martin et al. 1998; Sabsevitz et al. 2001; Stroup et al. 2003; Gleissner et al. 2004; Baxendale et al. 2006; Lineweaver et al. 2006; Binder et al. 2008b) after left ATL surgery. Patients are generally aware of these deficits, which adversely affect quality of life and employability (Perrine et al. 1995; Helmstaedter et al. 2003; Stroup et al. 2003; Lineweaver et al. 2004; Langfitt et al. 2007). Cognitive deficits from right ATL resection have been much less consistently observed (Loring et al. 1990a; Loring et al. 1995b; Pigot and Milner 1993); Pillon et al. 1999; Lee et al. 2002; Binder et al. 2008). Though the first priority in treating intractable epilepsy is seizure control, the importance of cognitive side effects for some patients undergoing left AT L surgery should not be underestimated or denied. Indeed, considerable resources have been devoted to developing methods for predicting and preventing cognitive morbidity, and many such methods are used routinely in the evaluation of surgical candidates despite ongoing controversy regarding their effectiveness.