Effect of transcranial direct current stimulation (tDCS) over the prefrontal cortex combined with cognitive training for treating schizophrenia: a sham-controlled randomized clinical trial
Abstract:Introduction: We report a transcranial direct current stimulation (tDCS) protocol over the dorsolateral prefrontal cortex (DLPFC) combined with cognitive training in schizophrenia.
Method:We assessed psychotic symptoms in nine patients using the Positive and Negative Syndrome Scale (PANSS). All evaluations were scored at baseline, at the end of the intervention protocol, and during a 4-week follow-up. The tDCS protocol consisted of 10 consecutive sessions over 5-day periods. We placed the cathode over the righ… Show more
“…The authors reported enhanced cognitive performance on word and picture N-back tasks and MCCB overall composite when CR was paired with tDCS. In a negative findings study ( 70 ), 10 patients were randomized to either active or sham tDCS (10 consecutive sessions over 5 days), with cognitive training (administration of n-back and sequence learning tasks) randomly applied during one of the tDCS sessions. The combined approach failed to improve clinical symptoms and cognitive performance.…”
Section: Review Of Physical Exercise and Tdcs Studiesmentioning
There is a burgeoning need for innovative treatment strategies to improve the cognitive deficits in schizophrenia. Cognitive remediation (CR) is effective at the group level, but the variability in treatment response is large. Given that CR may depend on intact neuroplasticity to produce cognitive gains, it is reasonable to combine it with strategies that harness patients’ neuroplastic potential. In this review, we discuss two non-pharmacological approaches that can enhance neuroplasticity and possibly augment the effects of CR in schizophrenia: physical exercise and transcranial direct current stimulation (tDCS). Substantial body of evidence supports the beneficial effect of physical exercise on cognition, and a handful of studies in schizophrenia have shown that physical exercise in conjunction with CR has a larger impact on cognition than CR alone. Physical exercise is thought to stimulate neuroplasticity through the regulation of central growth factors, and current evidence points to brain-derived neurotrophic factor as the potential underlying mechanism through which physical exercise might enhance the effectiveness of CR. tDCS has emerged as a potential tool for cognitive enhancement and seems to affect the cellular mechanisms involved in long-term potentiation (LTP). A few reports have demonstrated the feasibility of integrating tDCS with CR in schizophrenia, but there are insufficient data to determine if this multimodal approach leads to incremental performance gain in patients. Larger randomized controlled trials are necessary to understand the mechanisms of the combined tDCS–CR intervention. Future research should take advantage of new developments in neuroplasticity paradigms to examine the effects of these interventions on LTP.
“…The authors reported enhanced cognitive performance on word and picture N-back tasks and MCCB overall composite when CR was paired with tDCS. In a negative findings study ( 70 ), 10 patients were randomized to either active or sham tDCS (10 consecutive sessions over 5 days), with cognitive training (administration of n-back and sequence learning tasks) randomly applied during one of the tDCS sessions. The combined approach failed to improve clinical symptoms and cognitive performance.…”
Section: Review Of Physical Exercise and Tdcs Studiesmentioning
There is a burgeoning need for innovative treatment strategies to improve the cognitive deficits in schizophrenia. Cognitive remediation (CR) is effective at the group level, but the variability in treatment response is large. Given that CR may depend on intact neuroplasticity to produce cognitive gains, it is reasonable to combine it with strategies that harness patients’ neuroplastic potential. In this review, we discuss two non-pharmacological approaches that can enhance neuroplasticity and possibly augment the effects of CR in schizophrenia: physical exercise and transcranial direct current stimulation (tDCS). Substantial body of evidence supports the beneficial effect of physical exercise on cognition, and a handful of studies in schizophrenia have shown that physical exercise in conjunction with CR has a larger impact on cognition than CR alone. Physical exercise is thought to stimulate neuroplasticity through the regulation of central growth factors, and current evidence points to brain-derived neurotrophic factor as the potential underlying mechanism through which physical exercise might enhance the effectiveness of CR. tDCS has emerged as a potential tool for cognitive enhancement and seems to affect the cellular mechanisms involved in long-term potentiation (LTP). A few reports have demonstrated the feasibility of integrating tDCS with CR in schizophrenia, but there are insufficient data to determine if this multimodal approach leads to incremental performance gain in patients. Larger randomized controlled trials are necessary to understand the mechanisms of the combined tDCS–CR intervention. Future research should take advantage of new developments in neuroplasticity paradigms to examine the effects of these interventions on LTP.
“…The study was completed and the analysis carried out with 10 patients in each group. Referring to the pre‐assumptions of the covariance method, especially normality, and also to similar studies with similar sample sizes (Lotfi et al, ; Sayyah, Bagheri, Karimi, & Ghasemzadeh, ; Shiozawa et al, ), random selection of this sample size would be justifiable. The CBT, calcium supplement plus vitamin D, and mixed treatments were well tolerated and no serious event was observed during the study period.…”
Premenstrual syndrome (PMS) consists of repetitious physical and psychological symptoms. The symptoms occur during the luteal phase of the menstrual period and cease when the menstrual period starts. This study included pre-test and post-test experiments between a control group and a test group. The statistical population involved 40 females, chosen based on multistage cluster sampling. The participants were then divided into four groups to undergo treatment with calcium supplement plus vitamin D together with cognitive behavioral therapy (CBT), and were screened with the Premenstrual Syndrome Screening Test (PSST). The pre-test and post-test scores in the PSST, the General Health Questionnaire (GHQ-28), and Bell's Adjustment Inventory (BAI) were used as assessment tools (p < .05). According to the parameters of PMS symptoms, when evaluating the pre-test and post-test scores, the overall score of each individual in the experimental group was improved and a significant effect for the combination of calcium supplement plus vitamin D together with CBT was observed in comparison to the post-test control group. A comparison of multivariate analysis of covariance (MANCOVA) results collected from the pre-test and post-test scores revealed that the method of treatment was beneficial for PMS, adjustment, and general health.
“…37 Moreover, again, there was a different methodological aspect concerning the timing of stimulation sessions between the studies, which was more spaced in the first 37 and less spaced in the second study. 38 Finally, the third approach focused on anodal tDCS of the left DLPFC (F3) and catodal tDCS of the right orbitofrontal cortex (Fp2), which emphasizes the facilitation of the left DLPF. This is in line with the second approach, being considered of interest for the treatment of negative symptoms in SCZ.…”
Section: Discussionmentioning
confidence: 99%
“…Using the same electrode placement, Shiozawa et al 38 investigated the effect of the concomitant use of tDCS and cognitive training over clinical symptoms in a small sample of adult patients with SCZ (N = 10). All patients were using atypical antipsychotic medication.…”
Schizophrenia is a debilitating disease that affects approximately 1% of the population. Negative symptoms are among the major determinants of the functional impairment and a significant proportion of patients with negative symptoms will continue to experience these symptoms despite antipsychotic medications. There are promising results in the application of brain stimulation, particularly transcranial direct current stimulation (tDCS), for the reduction of negative symptoms of schizophrenia. However, findings are still controversial. This is a selective review of the literature published between 2011 and 2017 on use of tDCS in treatment of negative symptoms of schizophrenia. We included only randomized controlled trials where schizophrenia and negative symptoms were assessed using any psychometrically validated scale (eg, Positive and Negative Symptoms Scale or Scale for the Assessment of Negative Symptoms). Studies of participants with neurological conditions were excluded, as were those that did not report any symptom outcome variables. Only 5 studies are included. Three studies showed a decrease of negative symptoms. The other studies did not show any therapeutic effects of tDCS in the severity of positive and negative symptoms compared to controls. Our findings suggest that negative symptoms in schizophrenia can be treated with tDCS over the dorsolateral prefrontal cortex, but results are affected by several factors, such as the electrode montage, the concomitant medication, the homogeneity of the sample, the intensity of the tDCS treatment. Further randomized, double-blinded, sham-controlled studies in large samples are still needed to establish the effectiveness of the tDCS in the treatment of negative symptoms in schizophrenia, but there is the potential for tDCS to become a useful complementary treatment option in this population.
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