Dankinas Denisas, Mėlynytė Sigita, Šiurkutė Aldona, Dapšys Kastytis
Department of Neurobiology and Biophysics, Vilnius University, Vilnius, Lithuania.
Republican Vilnius Psychiatric Hospital, Vilnius, Lithuania.
Acta Med Litu. 2016;23(1):35-42. doi: 10.6001/actamedica.v23i1.3268.
It is important to prepare response in advance to increase the efficiency of its execution. The process of response preparation is usually studied using the precueing paradigm. In this paradigm subjects have to employ the preceding information about further imperative stimulus to perform proper response preparation, which shortens the reaction time of subsequent response execution. Previous studies detected the impairment of response preparation in schizophrenia only with the help of electroencephalographic parameters, but not with the assessing of reaction time. Therefore, in this study we attempted to find a behavioural parameter that could detect impairment in response preparation of schizophrenia patients. It was recently found that appropriate response preparation not only shortens the reaction time but also increases its stability, which is measured with the intra-individual reaction time variability. It was also revealed that response stability could better find cognitive dysfunction in some studies of schizophrenia disorder than classical behavioural parameters. Hence, the main goal of this study was to verify if intra-individual reaction time variability could detect the impairment of response preparation in schizophrenia patients. In order to achieve the main purpose, we carried out a study with 14 schizophrenia patients and 14 control group subjects. We used precueing paradigm in our research, in which participants had to employ information about stimulus probability for the proper response preparation. Our main result showed that despite the responses of schizophrenia patients were faster to the high-probability stimulus than to the low-probability one ( (1, 13) = 30.9, < 0.001), intra-individual reaction time variability did not differ in this group between the responses to more and less probable stimuli ( (1, 13) = 0.64, = 0.44). Results of the study suggest that people with schizophrenia were able to use precueing probabilistic information only to shorten their reaction time, but not to increase response stability. Therefore, it was found that intra-individual reaction time variability parameter could detect response preparation impairment in schizophrenia, and could be used in clinical purposes.
提前准备反应以提高执行效率很重要。反应准备过程通常使用预提示范式进行研究。在该范式中，受试者必须利用关于后续指令性刺激的先前信息来进行适当的反应准备，这会缩短后续反应执行的反应时间。先前的研究仅借助脑电图参数检测到精神分裂症患者反应准备的损害，而未通过反应时间评估来检测。因此，在本研究中，我们试图找到一个能够检测精神分裂症患者反应准备损害的行为参数。最近发现，适当的反应准备不仅会缩短反应时间，还会提高其稳定性，这通过个体内反应时间变异性来衡量。在一些精神分裂症障碍研究中还发现，反应稳定性比经典行为参数能更好地发现认知功能障碍。因此，本研究的主要目的是验证个体内反应时间变异性是否能检测精神分裂症患者反应准备的损害。为了实现主要目的，我们对14名精神分裂症患者和14名对照组受试者进行了一项研究。我们在研究中使用了预提示范式，其中参与者必须利用刺激概率信息进行适当的反应准备。我们的主要结果表明，尽管精神分裂症患者对高概率刺激的反应比对低概率刺激的反应更快（(1, 13) = 30.9, < 0.001），但该组中对可能性大小不同的刺激的反应，个体内反应时间变异性并无差异（(1, 13) = 0.64, = 0.44）。研究结果表明，精神分裂症患者能够仅利用预提示概率信息来缩短他们的反应时间，但不能提高反应稳定性。因此，发现个体内反应时间变异性参数可以检测精神分裂症患者的反应准备损害，并可用于临床目的。
