Department of Neurology, NIMHANS, Bangalore, India.
Department of Neuroimaging and Interventional Radiology (NIIR), NIMHANS, Bangalore, India.
Epilepsy Res. 2024 May;202:107353. doi: 10.1016/j.eplepsyres.2024.107353. Epub 2024 Mar 21.
The alpha rhythm has been a subject of research for the past few decades. Right-left alpha amplitude asymmetry is a common phenomenon. Several explanations have been proposed to explain this asymmetry, including differences in skull thickness. Our research aims to improve our understanding of the relationship between alpha asymmetry and skull thickness as measured by CT/MRI images.
We analyzed EEGs to study alpha rhythm characteristics. Alpha rhythm amplitude was measured using peak-to-peak values in O1 and O2 reference channels. Significant alpha asymmetry was defined as exceeding 20%. Skull thickness differences at corresponding locations were determined through CT/MRI scans. We examined the correlation between alpha and skull thickness asymmetry using Kruskal-Wallis, Spearman correlation, and median regression.
We examined 401 EEGs and images, categorizing patients into three groups based on alpha asymmetry. Group 1(n= 211) had less than 20 percent alpha asymmetry, Group 2(n=107) showed higher right-side alpha amplitudes, and Group 3(n= 83) displayed higher left-side alpha amplitudes. Our analysis revealed a significant association between groups with asymmetry and skull thickness differences (p<0.001), with a Spearman correlation (Rs) of -0.25 (p<0.001), indicating a significant negative correlation. After adjusting for age, sex, and handedness, Median Regression confirmed a statistically significant variation in skull thickness difference among the groups.
The present study involving a large cohort, the first of its kind, demonstrated a significant relationship between alpha amplitude asymmetry and skull thickness.
过去几十年来，alpha 节律一直是研究的主题。左右 alpha 幅度不对称是一种常见现象。已经提出了几种解释来解释这种不对称，包括颅骨厚度的差异。我们的研究旨在更好地理解 alpha 不对称与 CT/MRI 图像测量的颅骨厚度之间的关系。
我们分析了 EEG 以研究 alpha 节律特征。使用 O1 和 O2 参考通道中的峰峰值测量 alpha 节律幅度。超过 20%的明显 alpha 不对称被定义为显著不对称。通过 CT/MRI 扫描确定相应位置的颅骨厚度差异。我们使用 Kruskal-Wallis、Spearman 相关和中位数回归检验 alpha 与颅骨厚度不对称之间的相关性。
我们检查了 401 个 EEG 和图像，并根据 alpha 不对称将患者分为三组。第 1 组（n=211）的 alpha 不对称小于 20%，第 2 组（n=107）表现出较高的右侧 alpha 幅度，第 3 组（n=83）表现出较高的左侧 alpha 幅度。我们的分析表明，具有不对称性的组与颅骨厚度差异之间存在显著关联（p<0.001），Spearman 相关系数（Rs）为-0.25（p<0.001），表明存在显著的负相关。在调整年龄、性别和利手性后，中位数回归证实了组间颅骨厚度差异存在统计学上的显著变异。
本研究涉及一个大型队列，是此类研究中的首例，证明了 alpha 幅度不对称与颅骨厚度之间存在显著关系。
