Kaf Wafaa A, Danesh Ali A
Communication Sciences and Disorders, Missouri State University, Springfield, MO 65897, USA.
J Am Acad Audiol. 2008 Oct;19(9):696-707. doi: 10.3766/jaaa.19.9.5.
Two-channel auditory steady-state response (ASSR) recording at high and low MF (modulation frequency) most likely provides an insight about the response amplitude and latency from different directions at the brainstem level and at the thalamus or cortical level. Little is known about the combined relationship between MF (39 and 79 Hz) and electrode montages (ipsilateral and contralateral) to single AM (amplitude modulation) tones on the ASSR amplitude and latency.
To determine if ipsilateral versus contralateral response asymmetries are present at the brainstem level (79 Hz ASSR) and at the thalamus or cortical levels (39 Hz ASSR).
Descriptive and inferential statistics for interchannel ipsilateral and contralateral ASSR amplitude and latency to 79 and 39 Hz.
Twenty-five normal-hearing, right-handed young female adults participated in the study. All participants were right-handed, and their age ranged between 18 to 28 years (mean 24.5 +/- 1.6 years).
Ipsilateral and contralateral ASSR to 39 and 79 Hz MF and 100% AM stimuli were recorded at 500, 2000, and 4000 Hz carrier frequencies at 65 dB SPL. The ASSR amplitudes and phases were determined for each MF across Fc (carrier frequency) for the two channels to the test (right) ear. ASSR amplitude and latency between recording montages for each MF and across carrier frequency were compared by computing two-way repeated measures ANOVA.
The mean ipsilateral ASSR amplitudes to 39 Hz across frequency were slightly larger (228.6 +/- 61.6 microV) than the contralateral response amplitude (223.2 +/- 78 microV) while the mean ipsilateral 79 Hz amplitudes were smaller (127.3 +/- 114.8) compared to contralateral 79 Hz amplitude (154.6 +/- 112.7 microV). For latency response, the mean ipsilateral/contralateral latency difference, on average, was 1 msec or less for both MFs. Results, in normal female adults, indicated no significant interchannel ASSR asymmetries for amplitude and latency (p > 0.05) at the brainstem (79 Hz ASSR) and at the thalamus or cortical levels (39 Hz ASSR).
Interchannel ipsilateral and contralateral ASSR amplitude and latency to 79 and 39 Hz are not significantly different in normal, young female adults. Two-channel recording of ASSR to different MFs may be of clinical value in otoneurologic assessment.
在高低调制频率下进行双通道听觉稳态反应（ASSR）记录，极有可能提供关于脑干水平以及丘脑或皮质水平不同方向上反应幅度和潜伏期的见解。关于调制频率（39赫兹和79赫兹）与电极组合（同侧和对侧）对单个调幅（AM）音调的ASSR幅度和潜伏期之间的综合关系，目前所知甚少。
确定在脑干水平（79赫兹ASSR）以及丘脑或皮质水平（39赫兹ASSR）是否存在同侧与对侧反应不对称。
对79赫兹和39赫兹的通道间同侧和对侧ASSR幅度及潜伏期进行描述性和推断性统计。
25名听力正常、惯用右手的年轻成年女性参与了该研究。所有参与者均为惯用右手，年龄在18至28岁之间（平均24.5±1.6岁）。
在65分贝声压级下，于500赫兹、2000赫兹和4000赫兹载波频率处记录对39赫兹和79赫兹调制频率以及100%调幅刺激的同侧和对侧ASSR。针对测试（右）耳的两个通道，确定每个调制频率在不同载波频率下的ASSR幅度和相位。通过计算双向重复测量方差分析，比较每个调制频率以及不同载波频率下记录组合之间的ASSR幅度和潜伏期。
在不同频率下，同侧对39赫兹的ASSR平均幅度（228.6±61.6微伏）略大于对侧反应幅度（223.2±78微伏），而同侧79赫兹的平均幅度（127.3±114.8）小于对侧79赫兹的幅度（154.6±112.7微伏）。对于潜伏期反应，两种调制频率下同侧/对侧平均潜伏期差异平均为1毫秒或更小。结果表明，在正常成年女性中，脑干（79赫兹ASSR）以及丘脑或皮质水平（39赫兹ASSR）在幅度和潜伏期方面不存在显著的通道间ASSR不对称（p>0.05）。
在正常年轻成年女性中，79赫兹和39赫兹的通道间同侧和对侧ASSR幅度及潜伏期无显著差异。对不同调制频率的ASSR进行双通道记录可能在耳神经学评估中具有临床价值。
