Guehl Dominique, Burbaud Pierre, Lorenzi Christian, Ramos Christophe, Bioulac Bernard, Semal Catherine, Demany Laurent
Laboratoire Mouvement, Adaptation, Cognition, CNRS and Université Bordeaux 2, Bordeaux, France.
Neuropsychologia. 2008;46(9):2326-35. doi: 10.1016/j.neuropsychologia.2008.03.007. Epub 2008 Mar 22.
Previous research has suggested that Parkinson's disease (PD) impairs perceptual acuity in the temporal domain. In the present study, psychophysical tests assessing several aspects of auditory temporal processing were administered to a group of PD patients treated with bilateral subthalamic nucleus (STN) stimulation and to a normal control group. Each patient was tested in three clinical conditions: without treatment, with levodopa therapy, and during STN stimulation. In all three conditions, the patients showed a significant deficit in the detection of very short temporal gaps within noise bursts and in the discrimination between the durations of two well-detectable time intervals (circa 50ms) bounded by two temporally non-contiguous pairs of clicks. However, the patients showed no deficit in the detection of a temporal break produced by a local interval change in an otherwise isochronous sequence of 10 clicks spaced by 50-ms intervals. The latter result contradicts previous suggestions that PD slows down an internal clock or pacemaker involved in the perception of short durations. In this regard, we reinterpret previous evidence. Remarkably, the patients' deficits were not diminished by levodopa therapy; in contrast, STN stimulation slightly improved performance, overall. We tentatively ascribe the deficit observed in the gap-detection test to a dysfunctioning of the auditory cortex, impairing its ability to track rapid fluctuations in sound intensity. We argue that the deficit in the duration-discrimination test is the consequence of an impairment in memory and/or attention rather than in the perception of time per se.
先前的研究表明，帕金森病（PD）会损害时间领域的感知敏锐度。在本研究中，对一组接受双侧丘脑底核（STN）刺激治疗的PD患者和一个正常对照组进行了评估听觉时间处理几个方面的心理物理学测试。每位患者在三种临床状态下接受测试：未治疗、左旋多巴治疗以及STN刺激期间。在所有这三种状态下，患者在检测噪声突发内非常短的时间间隙以及区分由两对时间上不连续的咔嗒声界定的两个易于检测的时间间隔（约50毫秒）的持续时间方面均表现出明显缺陷。然而，患者在检测由以50毫秒间隔隔开的10次咔嗒声的等时序列中局部间隔变化产生的时间中断方面没有缺陷。后一结果与先前关于PD会减慢参与短持续时间感知的内部时钟或起搏器的建议相矛盾。在这方面，我们重新解释先前的证据。值得注意的是，左旋多巴治疗并未减轻患者的缺陷；相反，总体而言，STN刺激略微改善了表现。我们初步将在间隙检测测试中观察到的缺陷归因于听觉皮层功能失调，损害了其跟踪声音强度快速波动的能力。我们认为持续时间辨别测试中的缺陷是记忆和/或注意力受损而非时间本身感知受损的结果。
