Mishra Srikanta K, Dey Ratul, Davessar Jai Lal
Department of Special Education and Communication Disorders, New Mexico State University, Las Cruces, NM, 88003-8001, USA.
Department of Ear, Nose and Throat, GGS Medical College and Hospital, Baba Farid University of Health Sciences, Faridkot, Punjab, 151203, India.
J Assoc Res Otolaryngol. 2015 Dec;16(6):773-82. doi: 10.1007/s10162-015-0536-6. Epub 2015 Jul 22.
Unilateral hearing loss (UHL) leads to an imbalanced input to the brain and results in cortical reorganization. In listeners with unilateral impairments, while the perceptual deficits associated with the impaired ear are well documented, less is known regarding the auditory processing in the unimpaired, clinically normal ear. It is commonly accepted that perceptual consequences are unlikely to occur in the normal ear for listeners with UHL. This study investigated whether the temporal resolution in the normal-hearing (NH) ear of listeners with long-standing UHL is similar to those in listeners with NH. Temporal resolution was assayed via measuring gap detection thresholds (GDTs) in within- and between-channel paradigms. GDTs were assessed in the normal ear of adults with long-standing, severe-to-profound UHL (N = 13) and age-matched, NH listeners (N = 22) at two presentation levels (30 and 55 dB sensation level). Analysis indicated that within-channel GDTs for listeners with UHL were not significantly different than those for the NH subject group, but the between-channel GDTs for listeners with UHL were poorer (by greater than a factor of 2) than those for the listeners with NH. The hearing thresholds in the normal or impaired ears were not associated with the elevated between-channel GDTs for listeners with UHL. Contrary to the common assumption that auditory processing capabilities are preserved for the normal ear in listeners with UHL, the current study demonstrated that a long-standing unilateral hearing impairment may adversely affect auditory perception--temporal resolution--in the clinically normal ear. From a translational perspective, these findings imply that the temporal processing deficits in the unimpaired ear of listeners with unilateral hearing impairments may contribute to their overall auditory perceptual difficulties.
单侧听力损失（UHL）会导致大脑输入不均衡，并引起皮质重组。在单侧听力受损的听者中，虽然与受损耳朵相关的感知缺陷已有充分记录，但对于未受损的、临床正常耳朵的听觉处理情况却知之甚少。人们普遍认为，UHL听者的正常耳朵不太可能出现感知后果。本研究调查了长期患有UHL的听者的正常听力（NH）耳的时间分辨率是否与NH听者相似。通过在通道内和通道间范式中测量间隙检测阈值（GDT）来测定时间分辨率。在两个呈现水平（30和55分贝感觉级）下，对患有长期严重至极重度UHL的成年人（N = 13）的正常耳朵以及年龄匹配的NH听者（N = 22）的正常耳朵进行了GDT评估。分析表明，UHL听者的通道内GDT与NH受试者组的GDT没有显著差异，但UHL听者的通道间GDT比NH听者的GDT更差（相差超过2倍）。正常或受损耳朵的听力阈值与UHL听者升高的通道间GDT无关。与普遍认为的UHL听者的正常耳朵听觉处理能力得以保留的假设相反，当前研究表明，长期单侧听力损伤可能会对临床正常耳朵的听觉感知——时间分辨率——产生不利影响。从转化医学的角度来看，这些发现意味着单侧听力受损听者未受损耳朵的时间处理缺陷可能会导致他们整体的听觉感知困难。
