Atcherson Samuel R, Moore Page C
Department of Audiology and Speech Pathology, University of Arkansas at Little Rock/University of Arkansas for Medical Sciences, Little Rock.
Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock.
J Am Acad Audiol. 2014 Jun;25(6):576-83. doi: 10.3766/jaaa.25.6.7.
The middle latency response (MLR) is considered a valid clinical tool for assessing the integrity of cortical and subcortical structures. Several investigators have demonstrated that a rising frequency chirp stimulus is capable of eliciting not only larger wave V amplitudes but larger MLR components as well. However, the chirp has never been specifically examined in a hemispheric electrode montage setup that is typical for neurodiagnostic application and site-of-lesion testing.
The purpose of this study was to examine the effect of chirp, click, and toneburst stimuli on MLR waveform peak latency and peak-to-peak amplitude in a hemispheric electrode montage setup.
This study used a repeated-measures design.
A total of 10 young adult participants (3 males, 7 females) with normal hearing were recruited and had negative histories of audiologic, otologic, and neurologic involvement, and no reported language or learning difficulties.
MLR latencies (Na, Pa, Nb, and Pb) and peak-to-peak amplitudes (Na-Pa, Pa-Nb, and Nb-Pb) were measured for all conditions and were statistically evaluated for left hemisphere-right ear (C3-A2) and right hemisphere-left ear (C4-A1) recordings.
Statistical analyses revealed no significant difference between C3-A2 and C4-A1 peak-to-peak amplitudes; therefore, data were collapsed. Stimulus comparisons revealed that Na evoked by tonebursts were statistically prolonged compared with both chirp and click, and that both Na-Pa and Pa-Nb peak-to-peak amplitudes were statistically larger for chirps compared with both clicks and tonebursts, and for clicks compared with tonebursts.
The results of this study support the hypothesis that a chirp would offer a clinical advantage to the click and toneburst in overall peak-to-peak amplitude. As expected, normal-hearing participants did not exhibit hemispheric differences when comparing C3-A2 and C4-A1 peak-to-peak amplitudes demonstrating symmetric auditory brain function. However, chirp-evoked MLRs will require further study to determine its usefulness in clinical practice.
中潜伏期反应（MLR）被认为是评估皮质和皮质下结构完整性的一种有效的临床工具。几位研究者已经证明，上升频率的线性调频脉冲刺激不仅能够引出更大的V波振幅，还能引出更大的MLR成分。然而，线性调频脉冲从未在神经诊断应用和病变部位测试中典型的半球电极蒙太奇设置中进行过专门研究。
本研究的目的是在半球电极蒙太奇设置中，研究线性调频脉冲、短声和短纯音刺激对MLR波形峰潜伏期和峰间振幅的影响。
本研究采用重复测量设计。
共招募了10名听力正常的年轻成年参与者（3名男性，7名女性），他们有听力、耳科和神经科方面的阴性病史，且未报告有语言或学习困难。
在所有条件下测量MLR潜伏期（Na、Pa、Nb和Pb）和峰间振幅（Na-Pa、Pa-Nb和Nb-Pb），并对左半球-右耳（C3-A2）和右半球-左耳（C4-A1）记录进行统计学评估。
统计分析显示C3-A2和C4-A1峰间振幅之间无显著差异；因此，数据进行了合并。刺激比较显示，与线性调频脉冲和短声相比，短纯音引出的Na在统计学上延长，并且与短声和短纯音相比，线性调频脉冲的Na-Pa和Pa-Nb峰间振幅在统计学上更大，与短纯音相比，短声的峰间振幅也更大。
本研究结果支持这样的假设，即在线性调频脉冲的总体峰间振幅方面，线性调频脉冲相对于短声和短纯音具有临床优势。正如预期的那样，听力正常的参与者在比较C3-A2和C4-A1峰间振幅时未表现出半球差异，表明听觉脑功能对称。然而，线性调频脉冲诱发的MLR需要进一步研究以确定其在临床实践中的实用性。
