Cornelis Claudia, De Picker Livia J, Hulstijn Wouter, Dumont Glenn, Timmers Maarten, Janssens Luc, Sabbe Bernard G C, Morrens Manuel
Collaborative Antwerp Psychiatric Research Institute, University of Antwerp , Antwerp , Belgium ; University Psychiatric Center St. Norbertushuis , Duffel , Belgium.
Collaborative Antwerp Psychiatric Research Institute, University of Antwerp , Antwerp , Belgium ; Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen , Nijmegen , Netherlands.
Front Psychiatry. 2015 Jan 6;5:189. doi: 10.3389/fpsyt.2014.00189. eCollection 2014.
Speed of processing, one of the main cognitive deficits in schizophrenia is most frequently measured with a digit-symbol-coding test. Performance on this test is additionally affected by writing speed and the rate at which symbol-digit relationships are learned, two factors that may be impaired in schizophrenia. This study aims to investigate the effects of sensorimotor speed, short-term learning, and long-term learning on task performance in schizophrenia. In addition, the study aims to explore differences in learning effects between patients with schizophrenia and elderly individuals.
Patients with schizophrenia (N = 30) were compared with age-matched healthy controls (N = 30) and healthy elderly volunteers (N = 30) during the Symbol-Digit Substitution Test (SDST). The task was administered on a digitizing tablet, allowing precise measurements of the time taken to write each digit (writing time) and the time to decode symbols into their corresponding digits (matching time). The SDST was administered on three separate days (day 1, day 2, day 7). Symbol-digit repetitions during the task represented short-term learning and repeating the task on different days represented long-term learning.
The repetition of the same symbol-digit combinations within one test and the repetition of the test over days resulted in significant decreases in matching time. Interestingly, these short-term and long-term learning effects were about equal among the three groups. Individual participants showed a large variation in the rate of short-term learning. In general, patients with schizophrenia had the longest matching time whereas the elderly had the longest writing time. Writing time remained the same over repeated testing.
The rate of learning and sensorimotor speed was found to have a substantial influence on the SDST score. However, a large individual variation in learning rate should be taken into account in the interpretation of task scores for processing speed. Equal learning rates among the three groups suggest that unintentional learning in schizophrenia and in the elderly is preserved. These findings are important for the design of rehabilitation programs for schizophrenia.
加工速度是精神分裂症主要的认知缺陷之一，最常通过数字符号编码测试来衡量。该测试的表现还会受到书写速度和符号 - 数字关系学习速度的影响，而这两个因素在精神分裂症中可能受损。本研究旨在调查感觉运动速度、短期学习和长期学习对精神分裂症患者任务表现的影响。此外，该研究旨在探索精神分裂症患者与老年人在学习效果上的差异。
在符号 - 数字替代测试（SDST）期间，将30名精神分裂症患者与年龄匹配的健康对照者（30名）和健康老年志愿者（30名）进行比较。该任务在数字化平板电脑上进行，从而能够精确测量书写每个数字所需的时间（书写时间）以及将符号解码为相应数字所需的时间（匹配时间）。SDST在三个不同的日子（第1天、第2天、第7天）进行。任务期间符号 - 数字的重复代表短期学习，在不同日子重复该任务代表长期学习。
在一次测试中相同符号 - 数字组合的重复以及在不同日子重复测试导致匹配时间显著减少。有趣的是，这三种短期和长期学习效果在三组中大致相同。个体参与者在短期学习速度上表现出很大差异。一般来说，精神分裂症患者的匹配时间最长，而老年人的书写时间最长。重复测试时书写时间保持不变。
发现学习速度和感觉运动速度对SDST分数有重大影响。然而，在解释加工速度的任务分数时应考虑到学习速度存在较大的个体差异。三组学习速度相同表明精神分裂症患者和老年人的无意学习能力得以保留。这些发现对精神分裂症康复项目的设计具有重要意义。
