Working memory deficit in schizophrenia: a systematic review and meta-analysis of fMRI studies examining frontal and parietal brain activity

Introduction:
The role of functional magnetic resonance imaging (fMRI) findings in investigation of working memory (WM) deficit in schizophrenia patients is still debatable. The aim of the study was to investigate the role of fMRI findings of the frontal and parietal brain activity in investigation of WM deficit in schizophrenia patients.

Material and methods:
We used Medline, Embase, and the Cochrane Database to conduct a comprehensive search up to January 2023. Functional MRI findings of schizophrenia patients were compared with healthy patients in comparative studies for assessing their WM capacity in terms of dorsolateral prefrontal cortex and parietal region activation. The Cochrane Risk of Bias Assessment Tool was used to evaluate the research quality.

Results:
Ten trials and 676 schizophrenia patients were included in our analysis. For the comparative assessment of primary outcome – alteration in dorsolateral prefrontal cortex and parietal region activity in schizophrenic patients versus healthy controls – we found the pooled odds ratio (OR) of 1.58 [95% CI: 1.09-2.29], I² = 61% and p = 0.01 and risk ratio (RR) was 1.27 [95% CI: 1.06-1.53], I² = 55% and p = 0.01. The AUC value of 0.944 indicates a favourable overall diagnostic performance of fMRI for the diagnosis of schizophrenia.

Conclusions:
fMRI findings showing abnormalities in the parietal and frontal regions can be used to study schizophrenia patients’ WM deficits.