Department of Psychiatry and Psychotherapy, University of Regensburg, Universitaetsstrasse 84, 93053 Regensburg, Germany.
Neural Plast. 2014;2014:436146. doi: 10.1155/2014/436146. Epub 2014 May 19.
Subjective tinnitus is characterized by the conscious perception of a phantom sound which is usually more prominent under silence. Resting state recordings without any auditory stimulation demonstrated a decrease of cortical alpha activity in temporal areas of subjects with an ongoing tinnitus perception. This is often interpreted as an indicator for enhanced excitability of the auditory cortex in tinnitus. In this study we want to further investigate this effect by analysing the moment-to-moment variability of the alpha activity in temporal areas. Magnetoencephalographic resting state recordings of 21 tinnitus subjects and 21 healthy controls were analysed with respect to the mean and the variability of spectral power in the alpha frequency band over temporal areas. A significant decrease of auditory alpha activity was detected for the low alpha frequency band (8-10 Hz) but not for the upper alpha band (10-12 Hz). Furthermore, we found a significant decrease of alpha variability for the tinnitus group. This result was significant for the lower alpha frequency range and not significant for the upper alpha frequencies. Tinnitus subjects with a longer history of tinnitus showed less variability of their auditory alpha activity which might be an indicator for reduced adaptability of the auditory cortex in chronic tinnitus.
主观性耳鸣的特征是自觉感知到一种幻听，通常在安静环境下更为明显。在没有任何听觉刺激的静息状态记录中，持续存在耳鸣感知的受试者的颞区皮质α活动减少。这通常被解释为耳鸣听觉皮层兴奋性增强的指标。在这项研究中，我们希望通过分析颞区α活动的瞬间变异性来进一步研究这种效应。对 21 名耳鸣患者和 21 名健康对照者的脑磁图静息状态记录进行了分析，以评估颞区α频带（8-10 Hz）的平均和频谱功率变异性。低频α频带（8-10 Hz）的听觉α活动明显降低，但高频α频带（10-12 Hz）没有降低。此外，我们发现耳鸣组的α变异性明显降低。对于低频α频率范围，这一结果是显著的，而对于高频α频率则不显著。耳鸣病史较长的耳鸣患者的听觉α活动变异性较小，这可能是慢性耳鸣中听觉皮层适应性降低的一个指标。
