Using a standardized sound set to help characterize misophonia: The international affective digitized sounds

Misophonia is a condition characterized by negative affect, intolerance, and functional impairment in response to particular repetitive sounds usually made by others (e.g., chewing, sniffing, pen tapping) and associated stimuli. To date, researchers have largely studied misophonia using self-report measures. As the field is quickly expanding, assessment approaches need to advance to include more objective measures capable of differentiating those with and without misophonia. Although several studies have used sounds as experimental stimuli, few have used standardized stimuli sets with demonstrated reliability or validity. To conduct rigorous research to better understand misophonia, it is important to have an easily accessible, standardized set of acoustic stimuli for use across studies. Accordingly, in the present study, the International Affective Digitized Sounds (IADS-2), developed by Bradley and Lang [1], were used to determine whether participants with misophonia responded to certain standardized sounds differently than a control group. Participants were 377 adults (132 participants with misophonia and 245 controls) recruited from an online platform to complete several questionnaires and respond to four probes (arousal, valence, similarity to personally relevant aversive sounds, and sound avoidance) in response to normed pleasant, unpleasant, and neutral IADS-2 sounds. Findings indicated that compared to controls, participants with high misophonia symptoms rated pleasant and neutral sounds as significantly more (a) arousing and similar to trigger sounds in their everyday life, (b) unpleasant, and (c) likely to be avoided in everyday life. For future scientific and clinical innovation, we include a ranked list of IADS-2 stimuli differentiating responses in those with and without misophonia, which we call the IADS-M.

Methods
Group differences in sound ratings were examined using a two-way, mixed analysis of covariance (2 groups x 3 sound types, where “group” corresponds to participants with misophonia or controls, and “sound type” refers to positive, negative, or neutral sounds) on four dependent variables (ratings of valence, arousal, similarity, and avoidance). When statistically significant interactions were observed for sound type, pairwise comparisons were used to determine group differences on each dependent variable, as well as mean differences between sound type on each dependent variable.

All analyses were conducted using IBM SPSS27 statistical software. The first step in the data analytic plan included cleaning and screening the dataset by (a) inspecting all variables for data entry errors (none were observed), and (b) examining the normality of distributions across study variables. Next, bivariate correlations were explored to examine the relationships among variables and determine whether it would be appropriate to use any covariates. The Positive and Negative Affect Scale (PANAS), the Affect Intensity Measure (AIM), and gender were all found to significantly correlate with results and were initially included as covariates. Skewness and kurtosis levels did not exceed acceptable ranges (skewness < 2, kurtosis < 4).28

Finally, we ranked sounds according to a composite Z-score calculated by the sum of the Z scores from mean group differences on each sound for each dependent variable and listed the entire ranked stimuli as “IADS-M” sounds (See Table 2). Sounds listed first (e.g., writing, whistling) reflect the sounds that most differentiate individuals with misophonia from controls. Researchers using the IADS-M can determine how many sounds to include in future studies.

Detailed methods and procedures can be found in the published manuscript.

恐音症（Misophonia）是一种以对他人通常发出的特定重复性声音（如咀嚼、抽鼻子、敲笔）及相关刺激产生负面情绪、反感和功能受损为特征的病症。迄今为止，研究人员主要通过自我报告量表对恐音症展开研究。随着该领域的快速发展，评估方法亟需升级，纳入能够有效区分恐音症患者与健康对照者的客观测量手段。尽管已有部分研究将声音作为实验刺激，但极少有研究采用经信效度验证的标准化刺激集。为开展严谨的研究以深化对恐音症的理解，建立一套易于获取、可跨研究使用的标准化声学刺激集至关重要。据此，本研究采用由Bradley与Lang[1]开发的国际情感数字化声音库（International Affective Digitized Sounds, IADS-2），旨在探究恐音症参与者对特定标准化声音的反应是否与健康对照组存在差异。本研究的参与者为377名成年人，其中132名恐音症患者、245名健康对照者，均招募自线上平台，参与者需完成多份问卷，并针对标准化的愉悦、不快及中性IADS-2声音完成四项评定任务：唤醒度、效价、与个人相关厌恶声音的相似性，以及声音回避倾向。研究结果显示，与健康对照组相比，高恐音症症状参与者对愉悦及中性声音的评定显著更高：(a) 唤醒度与日常触发声音的相似性，(b) 不愉快程度，以及(c) 日常回避可能性。为推动后续科学与临床创新，我们编制了一份可区分恐音症患者与对照者反应的IADS-2刺激排序列表，命名为IADS-M。

方法
本研究采用双向混合协方差分析（2组×3声音类型，其中“组”对应恐音症参与者或健康对照组，“声音类型”指正性、负性或中性声音），针对四项因变量（效价、唤醒度、相似性及回避倾向的评定得分）检验声音评定的组间差异。当观察到声音类型存在统计学显著的交互效应时，采用两两比较以确定各因变量上的组间差异，以及各因变量上不同声音类型间的均值差异。

所有分析均采用IBM SPSS 27统计软件完成。数据分析流程的第一步为数据集清理与筛查：(a) 检查所有变量的录入错误（未发现错误），以及(b) 考察研究变量的分布正态性。随后，通过双变量相关分析探究变量间的关联，以确定是否需纳入协变量。结果显示，积极与消极情感量表（Positive and Negative Affect Scale, PANAS）、情感强度量表（Affect Intensity Measure, AIM）及性别均与研究结果存在显著相关，故最初将其作为协变量纳入分析。偏度与峰度值均处于可接受范围（偏度<2，峰度<4）[28]。

最终，我们根据复合Z分数对声音进行排序：复合Z分数由各因变量上每种声音的组间均值差异的Z分数求和得到，并将完整排序的刺激集命名为“IADS-M”声音（详见表2）。排序靠前的声音（如书写声、口哨声）是最能区分恐音症患者与健康对照者的声音。使用IADS-M的研究人员可根据需求确定后续研究中纳入的声音数量。

详细的方法与流程可参见已发表的论文。