Fuller R, Jahanshahi M
Department of Clinical Neurology, Institute of Neurology, The National Hospital for Neurology and Neurosurgery, London, UK.
J Neurol Neurosurg Psychiatry. 1999 Apr;66(4):502-9. doi: 10.1136/jnnp.66.4.502.
To assess willed actions in patients with schizophrenia using reaction time (RT) tasks that differ in the degree to which they involve volitionally controlled versus stimulus driven responses.
Ten patients diagnosed with schizophrenia and 13 normal controls of comparable age were tested. Subjects performed a visual simple RT (SRT), an uncued four choice reaction time (CRT), and a fully cued four choice RT task. A stimulus 1(S1)-stimulus 2(S2) paradigm was used. The warning signal/precue (S1) preceded the imperative stimulus (S2) by either 0 (no warning signal or precue) 200, 800, 1600, or 3200 ms.
The patients with schizophrenia had significantly slower RTs and movement times than normal subjects across all RT tasks. The unwarned SRT trials were significantly faster than the uncued CRT trials for both groups. For both groups, fully cued CRTs were significantly faster than the uncued CRTs. However, the S1-S2 interval had a differential effect on CRTs in the two groups. For the normal subjects fully cued CRTs and SRTs were equivalent when S1-S2 intervals were 800 ms or longer. A similar pattern of effects was not seen in the patients with schizophrenia, for whom the fully cued CRT were unexpectedly equivalent to SRT for the 200 ms interval and expectedly for the 1600 ms S1-S2 interval, but not the 3200 or 800 ms intervals.
Patients with schizophrenia were able to use advance information inherent in SRT or provided by the precue in fully cued CRT to speed up RT relative to uncued CRT. However, in the latter task, in which the volitional demands of preprogramming are higher since a different response has to be prepared on each trial, patients showed some unusual and inconsistent interval effects suggesting instability of attentional set. It is possible that future studies using RT tasks with higher volitional demands in patients with predominance of negative signs may disclose greater deficits in willed action in schizophrenia.
使用反应时间（RT）任务评估精神分裂症患者的意志行动，这些任务在涉及自主控制反应与刺激驱动反应的程度上有所不同。
对10名被诊断为精神分裂症的患者和13名年龄相仿的正常对照者进行测试。受试者执行视觉简单反应时间（SRT）、无提示四选一反应时间（CRT）和完全提示四选一RT任务。采用刺激1（S1）-刺激2（S2）范式。警告信号/预提示（S1）在指令刺激（S2）之前出现的时间为0（无警告信号或预提示）、200、800、1600或3200毫秒。
在所有RT任务中，精神分裂症患者的反应时间和运动时间明显比正常受试者慢。两组的无提示SRT试验均明显快于无提示CRT试验。对于两组，完全提示的CRT明显快于无提示的CRT。然而，S1-S2间隔对两组的CRT有不同影响。对于正常受试者，当S1-S2间隔为800毫秒或更长时，完全提示的CRT和SRT相当。在精神分裂症患者中未观察到类似的效应模式，对于他们来说，完全提示的CRT在200毫秒间隔时意外地与SRT相当，在1600毫秒S1-S2间隔时符合预期，但在3200或800毫秒间隔时并非如此。
相对于无提示的CRT，精神分裂症患者能够利用SRT中固有的提前信息或完全提示的CRT中的预提示来加快反应时间。然而，在后者的任务中，由于每次试验都必须准备不同的反应，预编程的意志要求更高，患者表现出一些不寻常且不一致的间隔效应，表明注意力集的不稳定性。未来对以阴性症状为主的患者使用具有更高意志要求的RT任务进行的研究，可能会揭示精神分裂症患者在意志行动方面更大的缺陷。
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