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Time Course of Postoperative Recovery of N ‐Acetyl‐Aspartate in Temporal Lobe Epilepsy
Author(s) -
Serles W.,
Li L. M.,
Antel S. B.,
Cendes F.,
Gotman J.,
Olivier A.,
Andermann F.,
Dubeau F.,
Arnold D. L.
Publication year - 2001
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1046/j.1528-1157.2001.01300.x
Subject(s) - epilepsy , temporal lobe , analysis of variance , creatine , medicine , nuclear medicine , epilepsy surgery , anesthesia , surgery , psychiatry
Summary: Purpose: To assess the time course of increases in N ‐acetyl‐aspartate/creatine (NAA/Cr), which can be measured using proton MR spectroscopic imaging ( 1 H‐MRSI), in patients with intractable nonlesional temporal lobe epilepsy (TLE) after successful epilepsy surgery. Methods: We performed pre‐ and postoperative 1 H‐MRSI in 16 seizure‐free (SF) patients and 16 not seizure‐free (NSF) TLE patients. We calculated a mixed‐design analysis of variance (ANOVA) between SF and NSF groups, ipsi‐ and contralateral to the side of operation, and pre‐ and postoperative NAA/Cr measurements. We applied nonlinear regression between pre‐ and postoperative NAA/Cr differences and the time interval between 1 H‐MRSI scans to fit a negative exponential model to NAA recovery. Results: Mixed‐design ANOVA revealed that (a) postoperative NAA/Cr was significantly higher in SF than in NSF patients (p = 0.02) and that (b) in the SF group, postoperative NAA/Cr values were significantly higher than preoperative values (p < 0.05) and returned to the normal range in most patients. According to our nonlinear regression model, in SF patients, there was a 50% increase relative to preoperative NAA/Cr values after 5.8 months, whereas an improvement of 95% was reached after 25 months. Conclusions: Our results extend preliminary observations of postoperative NAA recovery of SF patients by characterizing the time course of recovery as an exponential function with a half‐time of ∼6 months. The reversal of neuronal metabolic dysfunction remote from the epileptic focus may underlie the clinical observation of improvement of cognitive dysfunction after successful epilepsy surgery.