Barker L A, Andrade J, Romanowski C A J, Morton N, Wasti A
Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TP, UK.
Neuropsychologia. 2006;44(8):1413-24. doi: 10.1016/j.neuropsychologia.2005.12.005. Epub 2006 Jan 24.
Implicit or non-conscious cognition is traditionally assumed to be robust to pathology but Gomez-Beldarrain et al. recently showed deficits on a single implicit task after head injury. Laboratory research suggests that implicit processes dissociate. This study therefore examined implicit cognition in 20 head-injured patients and age- and IQ-matched controls using a battery of four implicit cognition tasks: a serial reaction time task (SRT), mere exposure effect task, automatic stereotype activation and hidden co-variation detection. Patients were assessed on an extensive neuropsychological battery, and MRI scanned. Inclusion criteria included impairment on at least one measure of executive function. The patient group was impaired relative to the control group on all the implicit cognition tasks except automatic stereotype activation. Effect size analyses using the control mean and standard deviation for reference showed further dissociations across patients and across implicit tasks. Patients impaired on implicit tasks had more cognitive deficits overall than those unimpaired, and a larger dysexecutive self/other discrepancy (DEX) score suggesting greater behavioural problems. Performance on the SRT task correlated with a composite measure of executive function. Head injury thus produced heterogeneous impairments in the implicit acquisition of new information. Implicit activation of existing knowledge structures appeared intact. Impairments in implicit cognition and executive function may interact to produce dysfunctional behaviour after head injury. Future comparisons of implicit and explicit cognition should use several measures of each function, to ensure that they measure the latent variable of interest.
传统上认为内隐或非意识认知对病理状态具有较强的耐受性，但戈麦斯 - 贝尔达兰等人最近发现头部受伤后在一项单一的内隐任务中存在缺陷。实验室研究表明内隐过程是分离的。因此，本研究使用一系列四项内隐认知任务对20名头部受伤患者以及年龄和智商匹配的对照组进行了内隐认知测试：序列反应时任务（SRT）、单纯曝光效应任务、自动刻板印象激活和隐藏协变检测。对患者进行了广泛的神经心理测试，并进行了MRI扫描。纳入标准包括至少一项执行功能测量指标受损。除自动刻板印象激活外，患者组在所有内隐认知任务上相对于对照组均受损。以对照组的均值和标准差为参考的效应量分析显示，患者之间以及内隐任务之间存在进一步的分离。在内隐任务上受损的患者总体上比未受损的患者有更多的认知缺陷，并且执行功能障碍自评/他评差异（DEX）得分更高，表明行为问题更大。SRT任务的表现与执行功能的综合测量指标相关。因此，头部受伤在新信息的内隐获取方面产生了异质性损伤。现有知识结构的内隐激活似乎完好无损。内隐认知和执行功能的损伤可能相互作用，导致头部受伤后出现功能失调行为。未来对内隐和外显认知的比较应使用每种功能的多种测量方法，以确保测量到感兴趣的潜在变量。
