Jaiser Stephan R, Baker Mark R, Baker Stuart N
Institute of Neuroscience, Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom.
Department of Neurology, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom.
PLoS One. 2016 Feb 22;11(2):e0149029. doi: 10.1371/journal.pone.0149029. eCollection 2016.
We investigated beta-band intermuscular coherence (IMC) in 92 healthy adults stratified by decade of age, and analysed variability between and within subjects. In the dominant upper limb, IMC was estimated between extensor digitorum communis and first dorsal interosseous as well as between flexor digitorum superficialis and first dorsal interosseous. In the ipsilateral lower limb, IMC was measured between medial gastrocnemius and extensor digitorum brevis as well as between tibialis anterior and extensor digitorum brevis. Age-related changes in IMC were analysed with age as a continuous variable or binned by decade. Intrasession variance of IMC was examined by dividing sessions into pairs of epochs and comparing coherence estimates between these pairs. Eight volunteers returned for a further session after one year, allowing us to compare intrasession and intersession variance. We found no age-related changes in IMC amplitude across almost six decades of age, allowing us to collate data from all ages into an aggregate normative dataset. Interindividual variability ranged over two orders of magnitude. Intrasession variance was significantly greater than expected from statistical variability alone, and intersession variance was even larger. Potential contributors include fluctuations in task performance, differences in electrode montage and short-term random variation in central coupling. These factors require further exploration and, where possible, minimisation. This study provides evidence that coherence is remarkably robust to senescent changes in the nervous system and provides a large normative dataset for future applications of IMC as a biomarker in disease states.
我们对92名按年龄十年分层的健康成年人的β波段肌间相干性（IMC）进行了研究，并分析了个体间和个体内的变异性。在优势上肢，测量了指总伸肌与第一背侧骨间肌之间以及指浅屈肌与第一背侧骨间肌之间的IMC。在同侧下肢，测量了腓肠肌内侧头与趾短伸肌之间以及胫骨前肌与趾短伸肌之间的IMC。将年龄作为连续变量或按十年分组，分析IMC与年龄相关的变化。通过将各时段划分为成对的epoch并比较这些对之间的相干性估计值，来检查IMC的时段内方差。八名志愿者在一年后返回进行了另一时段的测试，使我们能够比较时段内和时段间的方差。我们发现在近六十年的年龄范围内，IMC幅度没有与年龄相关的变化，这使我们能够将所有年龄的数据整理成一个综合的标准数据集。个体间变异性范围跨越两个数量级。时段内方差显著大于仅由统计变异性预期的值，时段间方差甚至更大。潜在因素包括任务表现的波动、电极安装的差异以及中枢耦合的短期随机变化。这些因素需要进一步探索，并在可能的情况下将其最小化。本研究提供了证据，表明相干性对神经系统的衰老变化具有显著的稳健性，并为IMC作为疾病状态生物标志物的未来应用提供了一个大型标准数据集。
