PURPOSE To explore the changes of gamma-aminobutyric acid (GABA) levels in the bilateral hippocampus and anterior cingulate cortex (ACC) of healthy control subjects and temporal lobe epilepsy (TLE) patients and the correlation of GABA levels with the clinical symptoms by quantitative magnetic resonance spectroscopy (MRS). METHODS N-acetylaspartate (NAA), creatine (Cr) as well as choline (Cho) and GABA levels in the bilateral hippocampus and ACC were measured in 40 TLE patients and 26 healthy normal control (NC) subjects with quantitative Meshcher-Garwood point resolved spectroscopy (MEGA-PRESS). The NAA/(Cho + Cr) and GABA/Cr ratios were compared between the NC and TLE groups. Comparisons were also made between the subgroups with lateralization (left TLE, Right TLE and Uncertain), short (<10 years) and longer (≥10 years) clinical seizure history (CSH), low (<1/month) and higher (≥1/month) seizure frequency (SF), with and without cognitive impairment (CI) in the TLE patients, and the antiepileptic medications were also analyzed. Further analyses of the clinical information and metabolite ratios between the TLE patients with and without CI were preformed. RESULTS The GABA/Cr ratio was significantly decreased in the bilateral hippocampus (left: P = 0.028, right: P = 0.035), while the NAA/(Cho + Cr) ratio was decreased only in the right hippocampus (RH) (P = 0.004) in TLE patients compared with that of the NCs. Despite that the NAA/(Cho + Cr) ratio had a persistent decrease tendency in bilateral hippocampus during the CSH, it only showed a significant difference in the RH. The GABA changes in the hippocampal and ACC regions were not consistent during different stages of the disease. In the bilateral hippocampus, the GABA/Cr ratio was decreased in the short seizure history (<10 years) TLE patients compared with NCs (left: P = 0.018, right: P = 0.012), whereas the long seizure history (≥10 years) TLE patients showed no difference with the NCs. However, in the ACC, the GABA/Cr ratio of the CI group was significantly decreased compared with that of NCs (P = 0.015). Further analysis showed that the TLE patients with CI had obviously atrophy of the gray matter volume (GMV) and total parenchymal brain volume (PBV); GABA/Cr ratio was decreased in ACC, but increased in bilateral hippocampus compared with that of no cognitive impairment (NOCI) group. CONCLUSION The GABA/Cr ratio was more valuable than the NAA/(Cho + Cr) ratio in evaluating the dynamic metabolite changes in TLE patients. Importantly, the GABA changes in the hippocampal and ACC regions were not consistent during different stages of the disease. In the bilateral hippocampus, the GABA/Cr ratio was decreased at the early stage, but recovered to normal levels later. The decreased GABA/Cr ratio in the ACC might indicate more cerebral cortex was involved and cause more obviously CI in TLE patients.

中文翻译：

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颞叶癫痫患者海马和前扣带回皮层中γ-氨基丁酸（GABA）的变化

目的通过定量磁力法探讨健康对照组和颞叶癫痫（TLE）患者双侧海马和前扣带回皮层（ACC）中γ-氨基丁酸（GABA）水平的变化及GABA水平与临床症状的相关性。共振光谱（MRS）。方法 测量 40 名 TLE 患者和 26 名健康正常对照 (NC) 受试者的双侧海马和 ACC 中的 N-乙酰天冬氨酸 (NAA)、肌酸 (Cr) 以及胆碱 (Cho) 和 GABA 水平，定量 Meshcher-Garwood 点解析光谱（MEGA-PRESS）。NAA/(Cho + Cr) 和 GABA/Cr 比率在 NC 和 TLE 组之间进行了比较。还在偏侧化（左 TLE、右 TLE 和不确定）、短（< TLE 患者的 10 年）和更长（≥10 年）临床癫痫发作史 (CSH)、低（<1/月）和更高（≥1/月）癫痫发作频率 (SF)，有或没有认知障碍 (CI) ，并且还分析了抗癫痫药物。进一步分析了有和没有 CI 的 TLE 患者之间的临床信息和代谢物比率。结果双侧海马的 GABA/Cr 比值显着降低（左：P = 0.028，右：P = 0.035），而 NAA/（Cho + Cr）比值仅在右侧海马（RH）中降低（P = 0.004) 在 TLE 患者中与 NCs 相比。尽管 CSH 期间 NAA/(Cho + Cr) 比值在双侧海马中具有持续下降的趋势，但仅在 RH 中显示出显着差异。在疾病的不同阶段，海马和 ACC 区域的 GABA 变化并不一致。在双侧海马中，短癫痫病史（<10 年）TLE 患者的 GABA/Cr 比值低于 NC（左：P = 0.018，右：P = 0.012），而长癫痫病史（≥10 年） ) TLE 患者与 NCs 没有差异。然而，在 ACC 中，CI 组的 GABA/Cr 比值与 NCs 相比显着降低（P = 0.015）。进一步分析显示，伴 CI 的 TLE 患者有明显的灰质体积（GMV）和总实质脑体积（PBV）萎缩；与无认知障碍 (NOCI) 组相比，ACC 中 GABA/Cr 比值降低，但双侧海马体中 GABA/Cr 比值升高。结论在评估 TLE 患者的动态代谢物变化时，GABA/Cr 比值比 NAA/(Cho + Cr) 比值更有价值。重要的是，在疾病的不同阶段，海马和 ACC 区域的 GABA 变化并不一致。双侧海马GABA/Cr比值早期下降，后期恢复正常。ACC 中 GABA/Cr 比值降低可能表明更多的大脑皮层受累，导致 TLE 患者更明显的 CI。