Data from: Cortical reorganisation during a 30-week tinnitus treatment program

Subjective tinnitus is characterised by the conscious perception of a phantom sound. Previous studies have shown that individuals with chronic tinnitus have disrupted sound-evoked cortical tonotopic maps, time-shifted evoked auditory responses, and altered oscillatory cortical activity. The main objectives of this study were to: (i) compare sound-evoked brain responses and cortical tonotopic maps in individuals with bilateral tinnitus and those without tinnitus; and (ii) investigate whether changes in these sound-evoked responses occur with amelioration of the tinnitus percept during a 30-week tinnitus treatment program. Magnetoencephalography (MEG) recordings of 12 bilateral tinnitus participants and 10 control normal-hearing subjects reporting no tinnitus were recorded at baseline, using 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz tones presented monaurally at 70 dBSPL through insert tube phones. For the tinnitus participants, MEG recordings were obtained at 5-, 10-, 20- and 30- week time points during tinnitus treatment. Results for the 500 Hz and 1000 Hz sources (where hearing thresholds were within normal limits for all participants) showed that the tinnitus participants had a significantly larger and more anteriorly located source strengths when compared to the non-tinnitus participants. During the 30-week tinnitus treatment, the participants’ 500 Hz and 1000 Hz source strengths remained higher than the non-tinnitus participants; however, the source locations shifted towards the direction recorded from the non-tinnitus control group. Further, in the left hemisphere, there was a time-shifted association between the trajectory of change of the individual’s objective (source strength and anterior-posterior source location) and subjective measures (using tinnitus reaction questionnaire, TRQ). The differences in source strength between the two groups suggest that individuals with tinnitus have enhanced central gain which is not significantly influenced by the tinnitus treatment, and may result from the hearing loss per se. On the other hand, the shifts in the tonotopic map towards the non-tinnitus participants’ source location suggests that the tinnitus treatment might reduce the disruptions in the map, presumably produced by the tinnitus percept directly or indirectly. Further, the similarity in the trajectory of change across the objective and subjective parameters after time-shifting the perceptual changes by 5 weeks suggests that during or following treatment, perceptual changes in the tinnitus percept may precede neurophysiological changes. Subgroup analyses conducted by magnitude of hearing loss suggest that there were no differences in the 500 Hz and 1000 Hz source strength amplitudes for the mild-moderate compared with the mild-severe hearing loss subgroup, although the mean source strength was consistently higher for the mild-severe subgroup. Further, the mild-severe subgroup had 500 Hz and 1000 Hz source locations located more anteriorly (i.e., more disrupted compared to the control group) compared to the mild-moderate group, although this was trending towards significance only for the 500Hz left hemisphere source. While the small numbers of participants within the subgroup analyses reduce the statistical power, this study suggests that those with greater magnitudes of hearing loss show greater cortical disruptions with tinnitus and that tinnitus treatment appears to reduce the tonotopic map disruptions but not the source strength (or central gain).

Usage Notes
READ MEBehavioural tinnitus distress data (TRQ)This spreadsheet contain the 5 recording session data from 12 tinnitus subjects.TRQ_data.xlsxT1 - tinnitus subject 1Magnetoencephalography files for tinnitus subject 1.T1.7zT2 - tinnitus subject 2Magnetoencephalography files for tinnitus subject 2.T2.7zT3 - tinnitus subject 3Magnetoencephalography files for tinnitus subject 3.T3.7zT4 - tinnitus subject 4Magnetoencephalography files for tinnitus subject 4.T4.7zT5 - tinnitus subject 5Magnetoencephalography files for tinnitus subject 5.T5.7zT6 - tinnitus subject 6Magnetoencephalography files for tinnitus subject 6.T6.7zT7 - tinnitus subject 7Magnetoencephalography files for tinnitus subject 7.T7.7zT8 - tinnitus subject 8Magnetoencephalography files for tinnitus subject 8.T8.7zT9 - tinnitus subject 9Magnetoencephalography files for tinnitus subject 9.T9.7zT10 - tinnitus subject 10Magnetoencephalography files for tinnitus subject 10.T10.7zT11 - tinnitus subject 11Magnetoencephalography files for tinnitus subject 11.T11.7zT12 - tinnitus subject 12Magnetoencephalography files for tinnitus subject 12.T12.7zControl subjects (10 total)Magnetoencephalography files from 10 normal (non-tinnitus) subjects. 1 MEG session per subject.Control.7z

主观性耳鸣表现为对幻听的主观感知。既往研究表明，慢性耳鸣患者存在声音诱发的皮层音调图破坏、时间移位的声音诱发电应以及皮层振荡活动的改变。本研究的主要目标为：（一）比较双侧耳鸣患者和无耳鸣个体在声音诱发的脑反应和皮层音调图方面的差异；（二）探究在30周耳鸣治疗程序中，耳鸣感知的改善是否会导致这些声音诱发电应的变化。对12名双侧耳鸣参与者和10名无耳鸣的正常听力对照受试者，在基线时记录了500 Hz、1000 Hz、2000 Hz和4000 Hz的纯音，通过插入式耳机以70 dBSPL单耳呈现。对于耳鸣参与者，在耳鸣治疗期间的5周、10周、20周和30周时间点进行了MEG记录。对于500 Hz和1000 Hz源（所有参与者的听阈均在正常范围内），与无耳鸣参与者相比，耳鸣参与者的源强度显著更大且更位于前方。在30周的耳鸣治疗过程中，参与者的500 Hz和1000 Hz源强度仍然高于无耳鸣参与者；然而，源位置向无耳鸣对照组记录的方向移动。此外，在左侧半球，个体客观（源强度和前后源位置）与主观（使用耳鸣反应问卷，TRQ）之间的时间移位关联。两组之间的源强度差异表明，耳鸣患者存在增强的中央增益，这并非显著受耳鸣治疗的影响，可能源于听力损失本身。另一方面，音调图向无耳鸣参与者源位置的移动暗示，耳鸣治疗可能减少了由耳鸣感知直接或间接产生的图中断裂。此外，在将感知变化的时间移位5周后，客观和主观参数变化轨迹的相似性表明，在治疗期间或之后，耳鸣感知的变化可能先于神经生理学变化。根据听力损失程度进行的亚组分析表明，与轻度至重度听力损失亚组相比，轻度至中度听力损失亚组的500 Hz和1000 Hz源强度幅度没有差异，尽管轻度至重度亚组的平均源强度始终较高。此外，与轻度至中度组相比，轻度至重度组的500 Hz和1000 Hz源位置更位于前方（即，与对照组相比更破坏），尽管这仅在500 Hz左侧半球源方面趋势显著。尽管亚组分析中参与者的数量较少，降低了统计功效，但本研究表明，听力损失程度较大者，耳鸣导致的皮层破坏更为严重，且耳鸣治疗似乎可减少音调图的中断，但不会减少源强度（或中央增益）。