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Location:Home>Research>Research Progress
 
First Evidence Shows Schizophrenia Patients are Able to Benefit from Action-based Encoding to Improve Everyday Life Working Memory Function in Following People’s Instructions
 
Author: Dr. Raymond Chan's Research Group      Update time: 2017/05/25
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      Schizophrenia is a brain disorder associated with a wide range of cognitive and emotional impairments. Working memory has been consistently demonstrated as a key cognitive marker for this disorder. However, the majority of studies examining working memory impairments in schizophrenia have been limited to conventional paradigms involving verbal and visuospatial materials, and it is unclear whether persons with schizophrenia may be impaired in action-based working memory and whether persons with schizophrenia can benefit from action-based encoding to improve their everyday life working memory abilities such as following instructions.

      In order to bridge such a knowledge gap, Drs. Simon LUI, Tian-xiao YANG, and Raymond CHAN from the Neuropsychology and Applied Cognitive Neuroscience (NACN) Laboratory, the CAS Key Laboratory of Mental Health, Institute of Psychology, and their international collaborators have adopted an innovative following instruction span task paradigm that involves varied encoding and recall conditions to 48 persons with schizophrenia and 48 matched healthy controls. The task requires participants to remember and follow a series of action commands in sequence, such as “spin the green rubber, and pick up the yellow rule then put it into the blue folder ”. This progress relies on working memory (T.-x. Yang, Allen, & Gathercole, 2016; T. Yang, Gathercole, & Allen, 2014). The visual display of the instruction task is shown in Figure 1.

Figure 1 Visual display of the instruction task 

There are three encoding conditions, participants 1) listened to the spoken instructions(Verbal task, VT); 2) or watched the experimenter performing the actions while listening to the spoken instructions(Experimenter-performed task, EPT); 3) or performed the actions by themselves while listening to the spoken instructions(Subject-performed task, SPT). In the recall stage, they recalled the instructions by oral repetition (verbal recall) or enactment (enacted recall). 

Persons with schizophrenia exhibited impairment in all conditions of following instructions (see Figure 2). More importantly, including action-based information in the encoding and retrieval stage facilitate performances of following instructions for both healthy controls and persons with schizophrenia. In both groups, memory performances of instructions was superior in SPT conditions compared to EPT condition, which in turn was higher than that in the VT condition. In addition, performances of enacted recall conditions were superior to that of verbal recall conditions.

Figure 2. Memory performances of instructions in different encoding and retrieval conditions in persons with schizophrenia and healthy controls. Encoding conditions include: VT = verbal task condition (pure verbal instructions), EPT = Experimenter-performed task, SPT = Subject-performed task SPT. 

In addition, we explored the relationship between following instructions and working memory. It turned out that in both groups, performances of the Letter-Number Span task (classic test for measuring working memory capacity) were correlated with memory of instructions in all conditions, indicating close relationship between following instructions and working memory and replicate previous findings in healthy adults and extended the findings to persons with schizophrenia. We further divided persons with schizophrenia into subgroups with and without working memory deficits according to the Letter-Number Span task. It turned out that only the subgroups of patients with working memory deficits displayed impairment in following instructions and those without working memory deficits had comparable performance of following instructions to the healthy controls (see Figure 3). These findings suggest that working memory deficit may be the major cause of impairment in following instructions in persons with schizophrenia.

 

Figure 3. Memory performances of following instructions in patients with schizophrenia with and without working memory deficits and healthy controls. Encoding conditions include: VT = verbal task condition (pure verbal instructions), EPT = Experimenter-performed task, SPT = Subject-performed task SPT.

In a similar study, Drs. YANG and CHAN have also shown that children with attention deficit hyperactivity disorder (ADHD) displayed impairments in following instructions compared to healthy controls, but children with ADHD could also benefit from action-based presentation and recall in the same way as their healthy counterparts(T.-x. Yang, Allen, Holmes, & Chan, 2017). 

Taken together, these findings have important implications for both clinicians and educators. On the one hand, the present findings shed light onto the importance of action-based processing in everyday life functions and are potential manipulating variable to be considered in cognitive rehabilitation for persons with schizophrenia or other disorders having working memory impairments. On the other hand, action-based methods of instruction-delivery may also enhance classroom learning for children with working memory deficits. Carers and family members should encourage persons with schizophrenia and ADHD to perform the actions or demonstrating the actions when teaching or asking the affected probands in addition to spoken instructions.

Dr. CHAN’s team is now undertaking studies incorporating this innovative behavioural task to neuroimaging paradigm to further examine the underlying neural mechanism of following instruction in clinical samples. Their ultimate goal is to translate their findings to clinical practice and help to improve the functional outcome of patients with working memory impairments such as schizophrenia and ADHD.

These two studies were supported by grants from the Beijing Training Project for Leading Talents in Science and Technology, the Beijing Municipal Science and Technology Commission Grant, the National Science Funding of China, the National Basic Research Programme, and the CAS/SAFEA International Partnership Program for Creative Research Teams, and the CAS Key Laboratory of Mental Health.

The paper is now available online from Schizophrenia Bulletin

-          Lui, S. S. Y., Yang, T. X., Ng, C. L. Y., Wong, P. T. Y., Wong, J. O. Y., Ettinger, U., Cheung, E. F. C., Chan, R. C. K.* Following instructions in patients with schizophrenia: The benefits of actions at encoding and recall. Schizophrenia Bulletin, DOI: https://doi.org/10.1093/schbul/sbx026 (link to paper: chrome://coba/content/container.xhtml?url=https://academic.oup.com/schizophreniabulletin/article/3844722/Following-Instructions-in-Patients-With)

-          Yang, T. X.*, Allen, R. J., Holmes, J., Chan, R. C. K. (2017). Impaired memory for instructions in children with attention-deficit hyperactivity disorders is improved by action at presentation and recall. Frontiers in Psychology, 8:39. doi:10.3389/fpsyg.2017.00039 

Related paper includes

-          Yang, T. X.*, Allen, R. J., Yu, Q. J., Chan, R. C. K. (2015). The influence of input and output modality on following instructions in working memory. Scientific Reports, 5:17657 | DOI: 10.1038/srep17657

-          Yang, T.-x.*, Allen, R. J., & Gathercole, S. E. (2016). Examining the role of working memory resources in following spoken instructions. Journal of Cognitive Psychology, 28(2), 186-198. doi: 10.1080/20445911.2015.1101118.

-          Yang, T.*, Gathercole, S. E., & Allen, R. J. (2014). Benefit of enactment over oral repetition of verbal instruction does not require additional working memory during encoding. Psychonomic Bulletin & Review, 21(1), 186-192. doi: 10.3758/s13423-013-0471-7 

 

Contact:
Raymond Chan
Institute of Psychology, Chinese Academy of Sciences
rckchan@psych.ac.cn

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