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Does Presurgical IQ Predict Seizure Outcome After Temporal Lobectomy ? Evidence from the Bozeman Epilepsy Consortium |
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| Authors: | Gordon J Chelune Richard I Naugle Bruce P Hermann William B Barr† Max R Trenerry‡ David W Loring§ Kenneth Perrine Esther Strauss¶ Michael Westerveld |
| Institution: | Section of Neuropsychology, Cleveland Clinic Foundation, Cleveland, Ohio;Department of Neurology, University of Wisconsin, Madison, Wisconsin;Hillside Hospital, Long Island Jewish Medical Center, New Hyde Park, NY;Division of Psychology, Mayo Clinic, Rochester, Minnesota;Department of Neurology, Medical College of Georgia, Augusta, Georgia;Department of Neurology, New York University Hospital, for Joint Diseases, New York, NY;Department of Psychology, University of Victoria, Victoria, British Columbia, Canada;Section of Neurosurgery, Yale University, New Haven, Connecticut, U.S.A. |
| Abstract: | Summary: Purpose: Considerable debate exists Concerning whether the presence of low preoperative IQ should be a contraindication for focal resective epilepsy surgery. Methods: We examined the relationship between baseline IQ scores and seizure outcome in 1,034 temporal lobectomy cases from eight epilepsy surgery centers participating in the Bozeman Epilepsy Consortium. Results: Those patients who continued to have seizures following surgery had statistically lower preoperative IQ scores than those who were seizure-free (p < 0.009), but only by 2.3 points. This small but statistically significant relationship was fairly robust; it was observed across seven of the eight centers, and indicates that the findings can be generalized. Among patients with IQ scores of ≤75, 32.8% continued to have seizures following surgery, whereas 23.8% and 16.9% were not seizure-free when IQ scores were between 76 and 109 and ≥110, respectively. Relative risk analyses revealed no significant increase in risk among patients with low IQ scores who had no structural lesions other than mesial temporal sclerosis. However, patients with IQ scores of ≤75 had nearly a fourfold (390%) increase in risk for continued seizures as compared with those with higher IQ scores if structural lesions were present. Conclusions: While our results suggest that preoperative IQ scores alone are not good predictors of seizure outcome and should not be used to exclude patients as potential surgical candidates. IQ scores can be useful for counseling patients and their families concerning the relative risks of surgery. |
| Keywords: | IQ Prediction Seizure outcome Relative risk |