Daniels C, Gottwald B, Pause B M, Sojka B, Mehdorn H M, Ferstl R
Department of Neurosurgery, University of Kiel, Kiel, Germany.
Clin Neurophysiol. 2001 Aug;112(8):1523-30. doi: 10.1016/s1388-2457(01)00590-9.
The aim of the study was to determine how odor processing is altered in patients with unilateral supratentorial brain tumors.
Olfactory event-related potentials (OERPs) were evaluated in 10 patients with unilateral brain tumors of the frontal or temporal lobe in response to linalool and allylcaproate. Both odors were presented monorhinally by a constant-flow olfactometer. In addition, 20 healthy subjects were examined. While sniffing, the subjects were asked to discriminate the two odors. EEG was recorded from 7 electrode positions (Fz, Cz, Pz, F3/4, P3/4). Amplitudes and latencies of 3 peaks (N1, P2, P3) were measured. To control for effects of modality-non-specific alterations on the olfactory components acoustic event-related potentials (AERPs) were registered by use of an oddball paradigm.
Patients with right-sided lesions showed distinct deficits in the discrimination task after stimulation of the right and left nostril. In contrast, patients with left-sided lesions only had an attenuation of correct reactions after left-sided stimulation. In the OERPs, patients with right-sided lesions showed P2- and P3-components with decreased amplitudes at parietal electrode positions. These alterations appeared after ipsi- and contralateral stimulation. Patients with left-sided lesions showed a significant effect of the side of stimulation. Their OERP-amplitudes were decreased after left-sided stimulation but not after right-sided stimulation. After right-sided olfactory stimulation a correlation between the olfactory and the acoustic ERP was seen in patients with right-sided lesions.
Olfactory performance of the participating patients was markedly reduced. Patients with right-sided lesions showed bilateral impairment, which would support the importance of the right hemisphere in olfaction. The alteration of the topographic distribution of P2- and P3-amplitudes in patients with right-sided lesions might reflect an impairment of early and late olfactory processing steps.
本研究旨在确定单侧幕上脑肿瘤患者的嗅觉处理过程是如何改变的。
对10例额叶或颞叶单侧脑肿瘤患者进行嗅觉事件相关电位（OERP）评估，以响应芳樟醇和己酸烯丙酯。两种气味均通过恒流嗅觉计单鼻孔呈现。此外，对20名健康受试者进行了检查。在嗅闻时，要求受试者辨别这两种气味。从7个电极位置（Fz、Cz、Pz、F3/4、P3/4）记录脑电图。测量3个峰（N1、P2、P3）的振幅和潜伏期。为了控制非模式特异性改变对嗅觉成分的影响，使用oddball范式记录听觉事件相关电位（AERP）。
右侧病变患者在刺激右侧和左侧鼻孔后，辨别任务中表现出明显缺陷。相比之下，左侧病变患者仅在左侧刺激后正确反应有所减弱。在OERP中，右侧病变患者在顶叶电极位置的P2和P3成分振幅降低。这些改变在同侧和对侧刺激后均出现。左侧病变患者表现出刺激侧的显著影响。他们的OERP振幅在左侧刺激后降低，但在右侧刺激后未降低。在右侧嗅觉刺激后，右侧病变患者的嗅觉和听觉ERP之间存在相关性。
参与研究的患者嗅觉功能明显降低。右侧病变患者表现出双侧损害，这支持了右半球在嗅觉中的重要性。右侧病变患者P2和P3振幅的地形图分布改变可能反映了早期和晚期嗅觉处理步骤的损害。
