Gecer Ibrahim Salih, Tabaru Alper, Yilmaz Beyhan, Kaya Elif, Kaya Tutar Nurhan, Gumuslu Bekircan, Oktay Mehmet Faruk
Department of Otorhinolaryngology, Istanbul Bakirkoy Research and Training Hospital, Istanbul 34147, Türkiye.
Department of Otorhinolaryngology, Van Research and Training Hospital, Van 65170, Türkiye.
World J Clin Cases. 2025 Oct 6;13(28):108180. doi: 10.12998/wjcc.v13.i28.108180.
Multiple sclerosis (MS) is known to affect many sensory systems, yet most auditory research in MS has focused on the afferent pathways, with relatively few studies examining efferent function. The brainstem is a common site for MS plaques, and the medial olivocochlear (MOC) system is located in the superior olivary complex (SOC) of the brainstem. The cochlear nuclei are also involved in the MOC reflex arc. Additionally, the temporal cortex can modulate the SOC and cochlear nucleus, so lesions in the brainstem or temporal cortex may affect the MOC reflex in MS.
To investigate efferent auditory system activity in patients with multiple sclerosis the MOC reflex.
The study included 50 patients with MS and 50 healthy controls. Patients with MS were divided into three subgroups according to cranial magnetic resonance imaging findings: Patients with brainstem lesions (Group 1, = 20); patients with temporal cortex lesions without brainstem involvement (Group 2, = 20); and patients without any lesions in the brainstem or temporal cortex (Group 3, = 10). Tympanometry, acoustic stapedial reflex thresholds, pure-tone audiometry, and transient-evoked otoacoustic emission (TEOAE) tests (with and without contralateral noise) were performed for all participants.
There was no significant difference in pure-tone hearing thresholds or baseline TEOAE amplitudes between the MS and control groups, indicating normal cochlear function in patients with MS; however, MOC reflex suppression was significantly reduced in patients with MS compared to controls ( = 0.021). In particular, Group 1 (MS with brainstem lesions) showed the lowest mean suppression values, which was significantly lower than that of Group 2 and the control group ( = 0.002). By contrast, Group 2 and Group 3 did not significantly differ from controls. Additionally, patients with MS exhibited a sex difference in MOC function: Male patients had significantly lower suppression compared to female patients both within Group 1 and in the MS group as a whole.
The findings indicate that the efferent auditory system (specifically the MOC reflex) is affected by MS. MOC reflex activity was most significantly decreased in patients with MS with brainstem lesions, while temporal cortex lesions alone did not appear to notably impair the MOC reflex. Diminished MOC activity may underlie various auditory difficulties in patients with MS (, hearing in noise), and loss of efferent suppression could contribute to symptoms such as hyperacusis or tinnitus in this population. Further studies are needed to better understand the relationship between MOC dysfunction and auditory symptoms in MS, as well as the potential diagnostic value of MOC testing in MS.
已知多发性硬化症（MS）会影响多个感觉系统，但MS的大多数听觉研究都集中在传入通路，而研究传出功能的相对较少。脑干是MS斑块的常见部位，内侧橄榄耳蜗（MOC）系统位于脑干的上橄榄复合体（SOC）中。耳蜗核也参与MOC反射弧。此外，颞叶皮质可以调节SOC和耳蜗核，因此脑干或颞叶皮质的病变可能会影响MS患者的MOC反射。
研究多发性硬化症患者传出听觉系统的活动——MOC反射。
该研究纳入了50例MS患者和50名健康对照者。根据头颅磁共振成像结果，将MS患者分为三个亚组：有脑干病变的患者（第1组，n = 20）；有颞叶皮质病变但无脑干受累的患者（第2组，n = 20）；脑干和颞叶皮质均无任何病变的患者（第3组，n = 10）。对所有参与者进行了鼓室图、镫骨肌声反射阈值、纯音听力测定和瞬态诱发耳声发射（TEOAE）测试（有或无对侧噪声）。
MS组和对照组之间的纯音听力阈值或基线TEOAE幅度没有显著差异，表明MS患者的耳蜗功能正常；然而，与对照组相比，MS患者的MOC反射抑制明显降低（P = 0.021）。特别是，第1组（有脑干病变的MS患者）的平均抑制值最低，显著低于第2组和对照组（P = 0.002）。相比之下，第2组和第3组与对照组没有显著差异。此外，MS患者在MOC功能方面存在性别差异：在第1组和整个MS组中，男性患者的抑制作用均明显低于女性患者。
研究结果表明，传出听觉系统（特别是MOC反射）受到MS的影响。有脑干病变的MS患者的MOC反射活动下降最为显著，而单独的颞叶皮质病变似乎并未明显损害MOC反射。MOC活动减弱可能是MS患者各种听觉困难（如噪声环境下听力）的基础，传出抑制的丧失可能导致该人群出现诸如听觉过敏或耳鸣等症状。需要进一步研究以更好地理解MS中MOC功能障碍与听觉症状之间的关系，以及MOC测试在MS中的潜在诊断价值。
