Makani Punitkumar, Thioux Marc, Pyott Sonja J, van Dijk Pim
Department of Otorhinolaryngology-Head and Neck Surgery, University of Groningen, University Medical Center Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands.
Graduate School of Medical Sciences (Research School of Behavioral and Cognitive Neurosciences), University of Groningen, FA30, P.O. Box 196, 9700 AD Groningen, The Netherlands.
Brain Sci. 2022 Sep 3;12(9):1192. doi: 10.3390/brainsci12091192.
Previous voxel-based morphometry (VBM) studies investigating tinnitus have reported structural differences in a variety of spatially distinct gray matter regions. However, the results have been highly inconsistent and sometimes contradictory. In the current study, we conducted a combined image- and coordinate-based meta-analysis of VBM studies investigating tinnitus to identify robust gray matter differences associated with tinnitus, as well as examine the possible effects of hearing loss on the outcome of the meta-analysis. The PubMed and Web of Science databases were searched for studies published up to August 2021. Additional manual searches were conducted for studies published up to December 2021. A whole-brain meta-analysis was performed using Seed-Based d Mapping with Permutation of Subject Images (SDM-PSI). Fifteen studies comprising 423 individuals with tinnitus and either normal hearing or hearing loss (mean age 50.94 years; 173 females) and 508 individuals without tinnitus and either normal hearing or hearing loss (mean age 51.59 years; 234 females) met the inclusion criteria. We found a small but significant reduction in gray matter in the left inferior temporal gyrus for groups of normal hearing individuals with tinnitus compared to groups of hearing-matched individuals without tinnitus. In sharp contrast, in groups with hearing loss, tinnitus was associated with increased gray matter levels in the bilateral lingual gyrus and the bilateral precuneus. Those results were dependent upon matching the hearing levels between the groups with or without tinnitus. The current investigation suggests that hearing loss is the driving force of changes in cortical gray matter across individuals with and without tinnitus. Future studies should carefully account for confounders, including hearing loss, hyperacusis, anxiety, and depression, to identify gray matter changes specifically related to tinnitus. Ultimately, the aggregation of standardized individual datasets with both anatomical and useful phenotypical information will permit a better understanding of tinnitus-related gray matter differences, the effects of potential comorbidities, and their interactions with tinnitus.
以往基于体素的形态学测量（VBM）研究对耳鸣进行调查时，报告了各种空间上不同的灰质区域存在结构差异。然而，结果高度不一致，有时甚至相互矛盾。在当前研究中，我们对调查耳鸣的VBM研究进行了基于图像和坐标的联合荟萃分析，以确定与耳鸣相关的稳健灰质差异，并研究听力损失对荟萃分析结果的可能影响。在PubMed和科学网数据库中检索截至2021年8月发表的研究。还对截至2021年12月发表的研究进行了额外的手动检索。使用基于种子的d映射与个体图像置换（SDM-PSI）进行全脑荟萃分析。15项研究纳入了423名患有耳鸣且听力正常或有听力损失的个体（平均年龄50.94岁；173名女性）以及508名无耳鸣且听力正常或有听力损失的个体（平均年龄51.59岁；234名女性），这些研究符合纳入标准。我们发现，与听力匹配的无耳鸣个体组相比，听力正常的耳鸣个体组左侧颞下回灰质有小幅但显著减少。与之形成鲜明对比的是，在有听力损失的组中，耳鸣与双侧舌回和双侧楔前叶灰质水平增加有关。这些结果取决于耳鸣组和非耳鸣组之间听力水平的匹配。当前的调查表明，听力损失是有耳鸣和无耳鸣个体皮质灰质变化的驱动力。未来的研究应仔细考虑包括听力损失、听觉过敏、焦虑和抑郁在内的混杂因素，以确定与耳鸣具体相关的灰质变化。最终，将标准化的个体数据集与解剖学和有用的表型信息进行汇总，将有助于更好地理解与耳鸣相关的灰质差异、潜在合并症的影响及其与耳鸣的相互作用。
