title: Weighing the value of memory loss in the surgical evaluation of left temporal lobe epilepsy: a decision analysis.
abstract: OBJECTIVE
  Anterior temporal lobectomy is curative for many patients with disabling medically refractory temporal lobe epilepsy, but carries an inherent risk of disabling verbal memory loss. Although accurate prediction of iatrogenic memory loss is becoming increasingly possible, it remains unclear how much weight such predictions should have in surgical decision making. Here we aim to create a framework that facilitates a systematic and integrated assessment of the relative risks and benefits of surgery versus medical management for patients with left temporal lobe epilepsy.
  
  
  METHODS
  We constructed a Markov decision model to evaluate the probabilistic outcomes and associated health utilities associated with choosing to undergo a left anterior temporal lobectomy versus continuing with medical management for patients with medically refractory left temporal lobe epilepsy. Three base-cases were considered, representing a spectrum of surgical candidates encountered in practice, with varying degrees of epilepsy-related disability and potential for decreased quality of life in response to post-surgical verbal memory deficits.
  
  
  RESULTS
  For patients with moderately severe seizures and moderate risk of verbal memory loss, medical management was the preferred decision, with increased quality-adjusted life expectancy. However, the preferred choice was sensitive to clinically meaningful changes in several parameters, including quality of life impact of verbal memory decline, quality of life with seizures, mortality rate with medical management, probability of remission following surgery, and probability of remission with medical management.
  
  
  CONCLUSIONS
  Our decision model suggests that for patients with left temporal lobe epilepsy, quantitative assessment of risk and benefit should guide recommendation of therapy. In particular, risk for and potential impact of verbal memory decline should be carefully weighed against the degree of disability conferred by continued seizures on a patient-by-patient basis.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, U.S.A.
authors.forename: Elliot H
authors.initials: EH
authors.lastname: Akama-Garren
authors.forename: Matt T
authors.initials: MT
authors.lastname: Bianchi
authors.forename: Catherine
authors.initials: C
authors.lastname: Leveroni
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Cole
authors.forename: Sydney S
authors.initials: SS
authors.lastname: Cash
authors.forename: M Brandon
authors.initials: MB
authors.lastname: Westover
mesh_terms: D000328:Adult; D002648:Child; D003661:Decision Support Techniques; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000601:surgery*; D006801:Humans; D008569:Memory Disorders / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011788:Quality of Life; D018570:Risk Assessment
keywords: Anterior temporal lobectomy; Markov process; Quality of life; Verbal memory decline