Supplementary Material for: Amplitude Modulated Noise for Tinnitus Suppression in Tonal and Noise-Like Tinnitus

Background: The phenomenon of short-term tinnitus suppression by different forms of acoustic stimulation is referred to as residual inhibition (RI). RI can be triggered in the majority of tinnitus cases and was found to be depending on the used intensity, length or types of sounds. Past research already stressed the impact of noise stimulation as well as the superiority of amplitude modulated (AM) pure tones at the individual tinnitus frequency for RI in tonal tinnitus. Recently a novel approach for the determination of noise-like tinnitus characteristics was proposed. Objectives: The aim of the present study was to investigate whether in participants with noise-like tinnitus RI can be increased by AM noise stimuli according to the individual tinnitus frequency range. Methods: For this purpose the individual tinnitus characteristics (noise-like and tonal tinnitus) of 29 people affected by tinnitus (mean age = 55.59, 7 females, mean tinnitus duration = 159.97 months) were assessed via customizable noise-band matching. The objective was to generate bandpass filtered stimuli according to the individual tinnitus sound (individualized bandpass filtered [IBP] sounds). Subsequently, various stimuli differing in bandpass filtering and AM were tested with respect to their potential to induce RI. Participants were acoustically stimulated with 7 different types of stimuli for 3 min each and had to rate the loudness of their tinnitus after each stimuli. Results: Results indicate a general efficacy of noise stimuli for the temporary suppression of tinnitus, but no significant differences between AM and unmodulated IBP. Significantly better effects were observed for the subgroup with noise-like tinnitus (n = 14), especially directly after stimulation offset. Conclusions: The study at hand provides further insights in potential mechanisms behind RI for different types of tinnitus. Beyond that, derived principles may qualify for new or extend current tinnitus sound therapies.背景：通过不同形式的声学刺激实现耳鸣短期抑制的现象，被称为残余抑制（Residual Inhibition，RI）。多数耳鸣病例中均可诱发残余抑制，且其效果受所用声音的强度、时长或类型影响。过往研究已证实噪声刺激的作用，以及在调性耳鸣的残余抑制中，针对个体耳鸣频率的调幅（Amplitude Modulated，AM）纯音具有更优效果。近期，学界提出了一种用于识别类噪声耳鸣特征的全新方法。 研究目的：本研究旨在探究，针对类噪声耳鸣受试者，基于个体耳鸣频率范围的调幅噪声刺激是否能够增强其残余抑制效果。 研究方法：为此，本研究通过可定制噪声带匹配法，对29名耳鸣患者（平均年龄55.59岁，其中女性7名，耳鸣平均病程159.97个月）的个体耳鸣特征（类噪声耳鸣与调性耳鸣）进行评估。本环节的目标是根据个体耳鸣声响生成带通滤波刺激声（个体化带通滤波（Individualized Bandpass Filtered，IBP）声）。随后，针对在带通滤波与调幅属性上存在差异的多种刺激，测试其诱发残余抑制的潜力。受试者接受7种不同类型的声学刺激，每种刺激持续3分钟，并需在每次刺激结束后对自身耳鸣响度进行评分。 研究结果：结果显示，噪声刺激对耳鸣具有普遍的暂时性抑制效果，但调幅与非调制的个体化带通滤波刺激之间未出现显著差异。其中，类噪声耳鸣亚组（n=14）的抑制效果显著更优，尤其在刺激结束即刻表现明显。 研究结论：本研究为不同类型耳鸣的残余抑制潜在机制提供了进一步的认知。此外，本研究推导得到的原则可用于开发新型耳鸣声学治疗方案，或对现有耳鸣声学疗法进行拓展。