Departments of Psychology and Neuroscience, Bio-Imaging Research Center, University of Georgia, Athens, GA, United States.
Neuroscience Institute, Georgia State University, Atlanta, GA, United States.
Schizophr Res. 2019 Jul;209:218-226. doi: 10.1016/j.schres.2019.04.014. Epub 2019 May 9.
Deviant auditory steady-state responses (aSSRs) in the gamma range (30-90 Hz) may be translational biomarkers for schizophrenia (SZ). This study tests whether aSSR deviations are (i) specific to SZ across the psychosis dimension, (ii) specific to particular frequency bands, and (iii) present in bipolar I disorder without psychosis (BDNP).
Beta (20-), low- (40-), and high-gamma (80-Hz) aSSRs were measured with EEG and compared across 113 SZ, 105 schizoaffective disorder (SAD), 99 bipolar disorder with psychosis (BDP), 68 BDNP, and 137 healthy comparison subjects (HC). Standard aSSR measures (single-trial power [STP] and inter-trial phase coherence [ITC]), as well as evoked responses to stimulus onsets/offsets and pre-stimulus power, were quantified. Multivariate canonical discriminant analysis was used to summarize variables that efficiently and maximally differentiated groups.
(i) Psychosis groups showed reduced responses on ITC 20 Hz, STP/ITC 40 Hz, STP/ITC 80 Hz, indicating dimensional reductions in aSSR across the psychosis spectrum not specific to aSSR frequency. For the 40- and 80-Hz ITCs there was greater reduction in SZ compared to SAD, possibly indexing cortical disruptions linked to psychosis without mood symptoms. (ii) All probands had elevated pre-stimulus power, possibly compromising neural entrainment to the steady-state stimuli. (iii) Onset/Offset and 80 Hz ITC responses were most important for group discrimination and showed dimensional reduction across the schizo-bipolar spectrum.
Deviant aSSRs were found across the schizo-bipolar spectrum at multiple frequencies with psychosis status and severity linked to greatest reductions at low and high gamma.
伽马范围（30-90 Hz）中的异常听觉稳态反应（aSSR）可能是精神分裂症（SZ）的转化生物标志物。本研究测试了 aSSR 偏差是否（i）在精神病维度上对 SZ 具有特异性，（ii）对特定频带具有特异性，以及（iii）在无精神病的双相 I 障碍（BDNP）中存在。
使用 EEG 测量了β（20-）、低（40-）和高伽马（80-Hz）aSSR，并在 113 例 SZ、105 例分裂情感障碍（SAD）、99 例有精神病的双相障碍（BDP）、68 例 BDNP 和 137 例健康对照者（HC）中进行了比较。量化了标准 aSSR 测量值（单试功率[STP]和试间相位相干性[ITC]），以及对刺激起始/结束和预刺激功率的诱发反应。使用多元典型判别分析来总结有效地和最大化区分组别的变量。
（i）精神病组的 ITC 20 Hz、STP/ITC 40 Hz、STP/ITC 80 Hz 的反应减少，表明 aSSR 在精神病谱上的维度减少，而不是特定于 aSSR 频率。对于 40 和 80 Hz 的 ITC，SZ 与 SAD 相比，减少幅度更大，这可能与无情绪症状的精神病相关的皮质中断有关。（ii）所有患者的预刺激功率升高，这可能会影响到对稳态刺激的神经同步。（iii）起始/结束和 80 Hz ITC 反应对于组间区分最重要，并且在精神分裂症-双相谱上表现出维度减少。
在多个频率下，在精神分裂症-双相谱中发现了异常的 aSSR，其精神病状态和严重程度与低频和高频的最大减少有关。
