Wilson W J
Division of Audiology, School of Health and Rehabilitation Sciences, Faculty of Health Sciences, University of Queensland, Brisbane, Qld 4072, Australia.
Clin Neurophysiol. 2004 May;115(5):1129-39. doi: 10.1016/j.clinph.2003.11.019.
To examine the relationship between the auditory brain-stem response (ABR) and its reconstructed waveforms following discrete wavelet transformation (DWT), and to comment on the resulting implications for ABR DWT time-frequency analysis.
ABR waveforms were recorded from 120 normal hearing subjects at 90, 70, 50, 30, 10 and 0 dBnHL, decomposed using a 6 level discrete wavelet transformation (DWT), and reconstructed at individual wavelet scales (frequency ranges) A6, D6, D5 and D4. These waveforms were then compared for general correlations, and for patterns of change due to stimulus level, and subject age, gender and test ear.
The reconstructed ABR DWT waveforms showed 3 primary components: a large-amplitude waveform in the low-frequency A6 scale (0-266.6 Hz) with its single peak corresponding in latency with ABR waves III and V; a mid-amplitude waveform in the mid-frequency D6 scale (266.6-533.3 Hz) with its first 5 waves corresponding in latency to ABR waves I, III, V, VI and VII; and a small-amplitude, multiple-peaked waveform in the high-frequency D5 scale (533.3-1066.6 Hz) with its first 7 waves corresponding in latency to ABR waves I, II, III, IV, V, VI and VII. Comparisons between ABR waves I, III and V and their corresponding reconstructed ABR DWT waves showed strong correlations and similar, reliable, and statistically robust changes due to stimulus level and subject age, gender and test ear groupings. Limiting these findings, however, was the unexplained absence of a small number (2%, or 117/6720) of reconstructed ABR DWT waves, despite their corresponding ABR waves being present.
Reconstructed ABR DWT waveforms can be used as valid time-frequency representations of the normal ABR, but with some limitations. In particular, the unexplained absence of a small number of reconstructed ABR DWT waves in some subjects, probably resulting from 'shift invariance' inherent to the DWT process, needs to be addressed.
This is the first report of the relationship between the ABR and its reconstructed ABR DWT waveforms in a large normative sample.
研究离散小波变换（DWT）后听觉脑干反应（ABR）与其重构波形之间的关系，并阐述其对ABR-DWT时频分析的影响。
记录120名听力正常受试者在90、70、50、30、10和0 dBnHL时的ABR波形，采用六级离散小波变换（DWT）进行分解，并在各个小波尺度（频率范围）A6、D6、D5和D4上进行重构。然后比较这些波形的一般相关性，以及因刺激强度、受试者年龄、性别和测试耳而产生的变化模式。
重构的ABR-DWT波形显示出3个主要成分：低频A6尺度（0 - 266.6 Hz）中的一个大振幅波形，其单峰潜伏期与ABR波III和V相对应；中频D6尺度（266.6 - 533.3 Hz）中的一个中等振幅波形，其前5个波潜伏期与ABR波I、III、V、VI和VII相对应；高频D5尺度（533.3 - 1066.6 Hz）中的一个小振幅、多峰波形，其前7个波潜伏期与ABR波I、II、III、IV、V、VI和VII相对应。ABR波I、III和V与其对应的重构ABR-DWT波之间的比较显示出强相关性，并且由于刺激强度、受试者年龄、性别和测试耳分组而产生的变化具有相似性、可靠性和统计学稳健性。然而，尽管存在相应的ABR波，但仍有少量（2%，即117/6720）重构的ABR-DWT波无法解释地缺失，这限制了这些发现。
重构的ABR-DWT波形可作为正常ABR的有效时频表示，但存在一些局限性。特别是，一些受试者中少量重构的ABR-DWT波无法解释地缺失，这可能是由于DWT过程固有的“平移不变性”导致的，需要加以解决。
这是在一个大型正常样本中关于ABR与其重构的ABR-DWT波形之间关系的首次报告。
