Abdul Wahab Noor Alaudin, Wahab Suzaily, Abdul Rahman Abdul Hamid, Sidek Dinsuhaimi, Zakaria Mohd Normani
Audiology Programme, School of Health Sciences, Universiti Sains Malaysia, Kelantan, Malaysia.; Audiology Programme, School of Rehabilitation Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Wilayah Persekutuan, Malaysia.
Department of Psychiatry, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Center, Wilayah Persekutuan, Malaysia.
Psychiatry Investig. 2016 Jan;13(1):82-8. doi: 10.4306/pi.2016.13.1.82. Epub 2015 Oct 14.
Electrophysiological studies, which are mostly focused on afferent pathway, have proven that auditory processing deficits exist in patients with schizophrenia. Nevertheless, reports on the suppressive effect of efferent auditory pathway on cochlear outer hair cells among schizophrenia patients are limited. The present, case-control, study examined the contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) in patients with schizophrenia.
Participants were twenty-three healthy controls and sixteen schizophrenia patients with normal hearing, middle ear and cochlear outer hair cells function. Absolute non-linear and linear TEOAEs were measured in both ears by delivering clicks stimuli at 80 dB SPL and 60 dB SPL respectively. Subsequently, contralateral suppression was determined by subtracting the absolute TEOAEs response obtained at 60 dBpe SPL during the absence and presence of contralateral white noise delivered at 65 dB HL. No attention tasks were conducted during measurements.
We found no significant difference in absolute TEOAEs responses at 80 dB SPL, in either diagnosis or ear groups (p>0.05). However, the overall contralateral suppression was significantly larger in schizophrenia patients (p<0.05). Specifically, patients with schizophrenia demonstrated significantly increased right ear contralateral suppression compared to healthy control (p<0.05).
The present findings suggest increased inhibitory effect of efferent auditory pathway especially on the right cochlear outer hair cells. Further studies to investigate increased suppressive effects are crucial to expand the current understanding of auditory hallucination mechanisms in schizophrenia patients.
电生理研究大多聚焦于传入通路，已证实精神分裂症患者存在听觉处理缺陷。然而，关于精神分裂症患者传出听觉通路对耳蜗外毛细胞的抑制作用的报道有限。本病例对照研究检测了精神分裂症患者瞬态诱发耳声发射（TEOAEs）的对侧抑制。
参与者为23名听力、中耳及耳蜗外毛细胞功能正常的健康对照者和16名精神分裂症患者。分别通过在80 dB SPL和60 dB SPL施加点击刺激来测量双耳的绝对非线性和线性TEOAEs。随后，通过减去在65 dB HL施加对侧白噪声时和未施加时在60 dBpe SPL获得的绝对TEOAEs反应来确定对侧抑制。测量过程中未进行注意力任务。
我们发现，在80 dB SPL时，无论是诊断组还是耳组，绝对TEOAEs反应均无显著差异（p>0.05）。然而，精神分裂症患者的总体对侧抑制明显更大（p<0.05）。具体而言，与健康对照相比，精神分裂症患者的右耳对侧抑制显著增加（p<0.05）。
目前的研究结果表明传出听觉通路的抑制作用增强，尤其是对右耳蜗外毛细胞的抑制作用。进一步研究以探讨增强的抑制作用对于扩展当前对精神分裂症患者幻听机制的理解至关重要。
