Comparative Study of Working Memory Ability in Schizophreniac Patients Using the Visual Digital and Visual Spatial N-back Tasks

目的：通过不同记忆负荷的视觉数字和视觉空间n-back任务,了解精神分裂症患者的工作记忆能力的受损情况。方法：选取精神分裂症患者33例（患者组）及正常对照50例（对照组）,分别完成视觉数字、视觉空间两种n-back范式任务,以信号检测论中的辨别力指标来评价受试者的工作记忆能力。结果：在各范式和记忆负荷下,患者组的辨别力低于对照组（P〈0.05）。随着记忆负荷的增大,无论是患者组还是对照组的辨别力都有显著下降。视觉数字n-back记忆负荷与分组的交互作用不显著（P=0.223）,视觉空间n-back记忆负荷与分组的交互作用显著（P=0.000）。结论：精神分裂症患者存在工作记忆能力受损,且其工作记忆能力的损害独立于精神症状之外;精神分裂症患者工作记忆的受损对视觉空间工作记忆负荷的增加表现得更为敏感。 Objective： To study the schizophreniac＇s working memory using the visual digital and visual spatial n-back in different memory loads. Methods： Thirty-three schizophreniac patients（case group） and 50 normal controls（control group） were recruited to accomplish the visual digital and visual spatial n-back in different memory loads. The performance of the working memory was evaluatedby discriminative power（d＇）. Results： The discriminative power（d＇） in the case group was significantly lower than that in the control group（P〈0.05）.With the increase of the memory load, the discriminative power（d＇） decreased significantly in the both groups. The interaction between the memory load and groups was evident（P = 0.000） in visual spatial n-back, while the interaction between the memory load and groups was not（P = 0.223） in visual digital n-back. Conclusion： Working memory impairments in schizophreniac patients are independent of the mental symptoms.Working memory impairments in schizophrenia patients are more sensitive to the increase of the spatial working memory loads.