Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
Clin Neurophysiol. 2013 Jan;124(1):70-82. doi: 10.1016/j.clinph.2012.06.003. Epub 2012 Jul 6.
To evaluate the test-retest reliability of event-related power changes in the 30-150 Hz gamma frequency range occurring in the first 150 ms after presentation of an auditory stimulus.
Repeat intracranial electrocorticographic (ECoG) recordings were performed with 12 epilepsy patients, at ≥1-day intervals, using a passive odd-ball paradigm with steady-state tones. Time-frequency matching pursuit analysis was used to quantify changes in gamma-band power relative to pre-stimulus baseline. Test-retest reliability was estimated based on within-subject comparisons (paired t-test, McNemar's test) and correlations (Spearman rank correlations, intra-class correlations) across sessions, adjusting for within-session variability. Reliability estimates of gamma-band response robustness, spatial concordance, and reproducibility were compared with corresponding measurements from concurrent auditory evoked N1 responses.
All patients showed increases in gamma-band power, 50-120 ms post-stimulus onset, that were highly robust across recordings, comparable to the evoked N1 responses. Gamma-band responses occurred regardless of patients' performance on behavioral tests of auditory processing, medication changes, seizure focus, or duration of test-retest interval. Test-retest reproducibility was greatest for the timing of peak power changes in the high-gamma range (65-150 Hz). Reliability of low-gamma responses and evoked N1 responses improved at higher signal-to-noise levels.
Early cortical auditory gamma-band responses are robust, spatially concordant, and reproducible over time.
These test-retest ECoG results confirm the reliability of auditory gamma-band responses, supporting their utility as objective measures of cortical processing in clinical and research studies.
评估听觉刺激后前 150ms 内出现的 30-150Hz 伽马频段相关事件的功率变化的复测信度。
使用稳态音的被动Odd-ball 范式，对 12 名癫痫患者进行至少 1 天间隔的重复颅内脑电（ECoG）记录。采用时频匹配追踪分析来量化相对于刺激前基线的伽马频带功率变化。基于个体内比较（配对 t 检验、McNemar 检验）和会话间相关性（Spearman 秩相关、组内相关）来估计复测信度，同时调整会话内变异性。伽马频带反应稳健性、空间一致性和可重复性的可靠性估计与同时进行的听觉诱发 N1 反应的相应测量值进行了比较。
所有患者在刺激后 50-120ms 时均表现出伽马频带功率增加，这种增加在记录中高度稳健，与诱发 N1 反应相当。伽马频带反应发生与否与患者听觉处理行为测试、药物变化、癫痫灶或复测间隔时间无关。在高伽马频带（65-150Hz）的峰值功率变化时间上，复测可重复性最佳。低伽马频带反应和诱发 N1 反应的可靠性在更高的信噪比水平上提高。
早期皮质听觉伽马频带反应稳健、空间一致且随时间可重现。
这些 ECoG 的复测结果证实了听觉伽马频带反应的可靠性，支持其作为皮质处理的客观指标在临床和研究中的应用。
