Memory changes following adjuvant temporo-parietal repetitive transcranial magnetic stimulation in schizophrenia

Assessment of memory deficits in psychiatric disorders: A systematic literature review

Memory deficits are observed across psychiatric disorders ranging from the prodrome of psychosis to common mental disorders such as anxiety, depression, and dissociative disorders. Memory deficits among patients recovering from psychiatric disorders could be directly related to the primary illness or secondary to the adverse effect of a treatment such as Electroconvulsive Therapy (ECT). The trouble in the meaningful integration of working-memory and episodic memory is the most commonly affected domain that requires routine assessments. An update on the recent trends of methods of assessment of memory deficits is the first step towards understanding and correcting these deficits to target optimum recovery. A systematic literature search was conducted from October 2018 to October 2022 to review the recent methods of assessment of memory deficits in psychiatric disorders. The definition of 'Memory deficit' was operationalized as 'selective processes of memory, commonly required for activities of daily living, and affected among psychiatric disorders resulting in subjective distress and dysfunction'. We included 110 studies, most of them being conducted in western countries on patients with schizophrenia. Other disorders included dementia and mild cognitive impairment. Brief Assessment of Cognition in Schizophrenia, Cambridge Automated Neuropsychological Test Battery, California Verbal Learning Test, Trail Making Test Part A and B, Rey Auditory Verbal Learning Test, Wechsler Memory Scale, Wechsler Adults Intelligence Scale-IV were the most common neuropsychological assessments used. Mini-Mental State Examination and Montreal Cognitive Assessment were the most common bedside assessment tools used while Squire Subjective Memory Questionnaire was commonly used to measure ECT-related memory deficits. The review highlights the recent developments in the field of assessment of memory deficits in psychiatric disorders. Findings recommend and emphasize routine assessment of memory deficits among psychiatric disorders in developing countries especially severe mental illnesses. It remains interesting to see the role of standardized assessments in diagnostic systems given more than a decade of research on memory deficits in psychiatric disorders.

Efficacy and safety of non-invasive brain stimulation on cognitive function for cognitive impairment associated with schizophrenia: A systematic review and meta-analysis

Based on existing evidence of the effects of the most commonly used non-invasive brain stimulation (NIBS), which includes transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), we conducted a meta-analysis to investigate the cognitive improvement and safety of NIBS on schizophrenia-related cognitive impairment. PubMed, EMBASE, Cochrane Library, and Web of Science were searched. The Cochrane Risk of Bias tool was used to assess the risk of bias of the included RCTs; Review Manager, version 5.4.1, was used to perform the statistical analysis. Twenty double-blind, randomized, sham-controlled trials involving 997 patients were included. As a result, no significant improvement in cognitive function was observed after NIBS treatment. However, the overall treatment effect of the two main NIBS modes (i.e., rTMS and tDCS) was associated with significantly larger improvements in negative symptoms and good tolerability in patients with schizophrenia compared to sham-controls (SMD = -0.56, 95% CI [-1.03, -0.08], p = 0.02, I2 = 88%). NIBS model and stimulus parameters influenced the effect of NIBS. More favorable effects were observed in patients who received rTMS stimulation (SMD = 0.25, 95% CI [0.01, 0.49], p = 0.04, I2 = 0%) in the left dorsolateral prefrontal cortex with a stimulation intensity of 20 Hz (p = 0.004) for a period longer than 1 month (p < 0.05). Yet, due to the limited number of included studies and heterogeneity in both study design and target population, the results of this analysis need to be interpreted with caution.

10 Hz repetitive transcranial magnetic stimulation (rTMS) may improve cognitive function: An exploratory study of schizophrenia patients with auditory hallucinations

Objectives

Cognitive impairment in schizophrenia patients with auditory hallucinations is more prominent compared to those without. Our study aimed to investigate the cognitive improvement effects of 10 Hz repetitive transcranial magnetic stimulation (rTMS) over the left dorsolateral prefrontal cortex (DLPFC) in schizophrenia with auditory hallucinations.

Methods

A total of 60 schizophrenic patients with auditory hallucinations in this study were randomly assigned to sham or active group. Both groups received 10 Hz or sham rTMS targeted in left DLPFC for 20 sessions. The Positive and Negative Syndrome Scale (PANSS), the Auditory Hallucination Rating Scale (AHRS), the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and the Udvalg for Kliniske Under-sogelser (UKU) side effect scale were used to measure psychiatric symptoms, auditory hallucinations, cognition, and side reaction, respectively.

Results

Our results indicated that the active group experienced greater improvements in RBANS-total score (P = 0.043) and immediate memory subscale score (P = 0.001). Additionally, the PANSS-total score, negative and positive subscale score were obviously lower in the active group compared to the sham group (all P < 0.050). Furthermore, our study found that the improvement of RBANS-total score was positively associated with the decline of positive factor score, and the improvement of language score in RBANS was positively associated with the reduction in PANSS-total scale, negative and positive subscale score in the real stimulation group (all P < 0.050).

Conclusion

Our results demonstrated that a four-week intervention of 10 Hz rTMS over the left DLPFC can improve cognition (particularly immediate memory) among schizophrenia patients with auditory hallucinations. Future studies with larger sample size are needful to verify our preliminary findings.