Background:

Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a disorder of GABA degradation with use-dependent downregulation of postsynaptic GABA_A/B receptors. We aim to measure the resulting cortical excitation: inhibition ratio using transcranial magnetic stimulation.

Methods:

In this single-center observational study, 18 subjects with SSADHD and 8 healthy controls underwent transcranial magnetic stimulation. Resting motor threshold, cortical silent period, and long-interval intracortical inhibition were measured in both groups. Resting motor threshold in focal epilepsy patients from an institutional transcranial magnetic stimulation database were also included.

Results:

SSADHD subjects had higher resting motor threshold than healthy controls but lower relative to focal epilepsy patients. Resting motor threshold decreased with age in all groups. Cortical silent period was longer in SSADHD subjects than in healthy controls. No difference was detected in long-interval intracortical inhibition between the 2 groups.

Conclusion:

Findings suggest abnormal corticospinal tract physiology in SSADHD, but with preserved developmental trajectory for corticospinal tract maturation. Defining features of these transcranial magnetic stimulation metrics in SSADHD will be better elucidated through this ongoing longitudinal study.

中文翻译：

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琥珀酸半醛脱氢酶缺乏症的经颅磁刺激：皮质兴奋性成熟轨迹的测量

背景：

_{琥珀酸半醛脱氢酶缺乏症 (SSADHD) 是一种 GABA 降解障碍，突触后 GABA A/B}受体使用依赖性下调。我们的目标是测量由此产生的皮质兴奋：使用经颅磁刺激的抑制比。

方法：

在这项单中心观察性研究中，18 名 SSADHD 受试者和 8 名健康对照者接受了经颅磁刺激。两组均测量静息运动阈值、皮质静默期和长间隔皮质内抑制。来自机构经颅磁刺激数据库的局灶性癫痫患者的静息运动阈值也包括在内。

结果：

SSADHD 受试者的静息运动阈值高于健康对照组，但低于局灶性癫痫患者。所有组的静息运动阈值都随着年龄的增长而降低。与健康对照组相比，SSADHD 受试者的皮质静默期更长。两组之间的长间隔皮质内抑制没有检测到差异。

结论：

研究结果表明 SSADHD 中的皮质脊髓束生理学异常，但皮质脊髓束成熟的发育轨迹得以保留。通过这项正在进行的纵向研究，将更好地阐明 SSADHD 中这些经颅磁刺激指标的特征。