Jones S J, Byrne C
Department of Clinical Neurophysiology, The National Hospital for Neurology and Neurosurgery, London, UK.
Electroencephalogr Clin Neurophysiol. 1998 Jul;108(4):355-60. doi: 10.1016/s0168-5597(98)00009-4.
Auditory evoked potentials were recorded to onset and offset of synthesised instrumental tones in 40 normal subjects, 20 right-handed for writing and 20 left-handed. The majority of both groups showed a T-complex which was larger at the right temporal electrode (T4) than the left (T3). In the T4-T3 difference waveforms, the mean potential between latencies of 130 and 165 ms was negative in all right-handed subjects except two for whom the waveforms were marginally positive-going. Amongst the left-handers, however, this converse asymmetry was seen in 7 subjects, 5 of them more than 2 standard deviations from the mean of the right-handed group. The degree of asymmetry was not significantly correlated with the degree of left-handedness according to the Edinburgh Handedness Inventory. Asymmetry of the T-complex to instrumental tones appears to reflect the lateralisation of auditory 'musical' processing in the temporal cortex, confirming evidence from other sources including PET that this is predominantly right-sided in the majority of individuals. The proportion of left-handers showing the converse laterality is roughly in accordance with those likely to be right-hemisphere-dominant for language. If linguistic and 'musical' processes are consistently located in opposite hemispheres, AEPs to complex tones may prove a useful tool in establishing functional lateralisation.
对40名正常受试者（20名右手书写者和20名左手书写者）记录了对合成乐器音调起始和结束时的听觉诱发电位。两组中的大多数人都表现出一种T复合波，其在右侧颞电极（T4）处比左侧（T3）处更大。在T4 - T3差值波形中，除两名受试者波形略呈正向外，所有右手书写者在130至165毫秒潜伏期之间的平均电位均为负。然而，在左撇子中，7名受试者出现了这种相反的不对称性，其中5人的不对称程度比右手书写者组的平均值高出2个标准差以上。根据爱丁堡手性量表，不对称程度与左撇子程度无显著相关性。T复合波对乐器音调的不对称性似乎反映了颞叶皮质中听觉“音乐”处理的侧化，这与包括PET在内的其他来源的证据一致，表明在大多数个体中这种侧化主要在右侧。表现出相反侧化的左撇子比例大致与那些可能以右半球为主导语言的比例一致。如果语言和“音乐”过程始终位于相反的半球，那么对复合音调的听觉诱发电位可能会成为确定功能侧化的有用工具。
