Transcranial alternating current stimulation for chronic insomnia: A systematic review

Effects of insomnia treatments on cognitive function: A meta-analysis of randomized controlled trials

BACKGROUND

Globally, insomnia has been shown to impact cognitive function, which has prompted the exploration of effective treatments to enhance cognitive outcomes. Both pharmacological and non-pharmacological interventions vary in their effects, indicating that further research for optimized therapeutic strategies is needed.

METHODS

Searches of PubMed, EMBASE, Web of Science, the Cochrane Library, and PsychInfo from database inception until August 2024 were conducted to identify relevant randomized controlled studies investigating the impacts of insomnia treatments on cognitive function. The standardized mean difference (SMD) and 95% confidence interval (CI) were calculated for all studies. Sensitivity analysis, publication bias, and meta-regression were performed.

RESULTS

A total of 14,829 records were retrieved, with 24 randomized controlled studies assessing the impact of insomnia treatment on cognition. Pooled analysis indicated that non-pharmacological interventions significantly enhanced cognitive function (SMD: 0.27, 95% CI: 0.04-0.49, p = 0.019), with notable improvements observed in memory (SMD: 1.18, 95% CI: 0.25-2.12, p = 0.013), attention (SMD: 0.32, 95% CI: 0.15-0.50, p < 0.001), and daily living activities (SMD: 0.29, 95% CI: 0.20-0.39, p < 0.001) based on self-reported measures. Longer follow-up periods were associated with more pronounced cognitive benefits (SMD: 0.34, 95% CI: 0.14-0.54, p = 0.001).

CONCLUSIONS

The critical role of insomnia treatments, particularly non-pharmacological interventions, in improving cognitive function is highlighted, emphasizing the importance of tailored therapeutic approaches to optimize cognitive outcomes and overall well-being.

Efficiency and safety of continuous theta burst stimulation for primary insomnia: A randomized clinical trial

OBJECTIVES

Primary insomnia is a substantial public health burden, but current treatments for this disorder have limited effectiveness and adherence. Herein, we aimed to investigate the efficacy and safety of continuous theta burst stimulation (cTBS) for the treatment of primary insomnia.

METHODS

This two-armed, randomized, sham-controlled trial was conducted at Peking University Sixth Hospital and local community clinics. A total of 46 patients with primary insomnia were recruited and randomly allocated to either the cTBS group or sham group. Forty-one patients completed 10 sessions of cTBS or sham intervention and follow-up assessments.

RESULTS

After the intervention, the severity of insomnia was significantly lower in the cTBS group than in the sham group, with a large effect size (Cohen's d = -1.938). Additionally, 52.4 % of patients in the cTBS group achieved a response (Insomnia Severity Index score reduction ≥8), whereas only 4 % of patients in the sham group achieved a response. The duration of objective total sleep time and slow-wave sleep were higher in the cTBS group than in the sham group. The degree of anxiety was lower in the cTBS group than in the sham group. There were no significant differences in depression, sleepiness, or cognitive function between the cTBS and sham groups. During follow-up, the sleep quality of the cTBS group significantly improved and remained stable at the 6-month follow-up.

CONCLUSION

In this randomized clinical trial, cTBS improved insomnia symptoms and was generally well tolerated, thus supporting the further development of cTBS for the treatment of primary insomnia.

Efficacy of transcranial alternating current stimulation in treating chronic insomnia and the impact of age on its effectiveness: A multisite randomized, double-blind, parallel-group, placebo-controlled study

OBJECTIVE

Insomnia is a significant health issue associated with various systemic diseases. Transcranial alternating current stimulation (tACS) has been proposed as a potential intervention for insomnia. However, the efficacy and mechanisms of tACS in chronic insomnia remain unclear. Accordingly, this study aimed to investigate the efficacy of tACS in treating chronic insomnia in adults and assess the impact of age on its effectiveness using a large sample from two centers.

METHODS

A total of 120 participants with chronic insomnia underwent 20 daily sessions of tACS (duration: 40 min, frequency: 77.5 Hz, and intensity: 15 mA) or sham tACS targeting the forehead and both mastoid areas over 4 weeks. Assessments were conducted at baseline, post-treatment, and 4-week follow-up. Primary outcomes included sleep quality and efficiency, onset latency, total sleep time, and daily disturbances. Secondary outcomes included depression, anxiety, and clinical impression.

RESULTS

Compared with the control group, the tACS group demonstrated improved sleep quality and efficiency, increased total sleep time, and reduced daily disturbance (all ps < 0.01). Moreover, tACS had a significant effect on clinical impression (p < 0.001), but not depression and anxiety scores. Subgroup analyses revealed that older participants experienced significant benefits from tACS in sleep quality, efficiency, and overall insomnia reduction at post-treatment and follow-up (p < 0.001). Notably, improved insomnia correlated with attenuated depressive and anxiety symptoms.

CONCLUSIONS

These findings suggest that tACS may be an effective intervention for chronic insomnia within an eight-week timeframe, and age affects the response to tACS in terms of insomnia improvement.

Transcranial alternating current stimulation for schizophrenia: a systematic review of randomized controlled studies

Background

In randomized clinical trials (RCTs) investigating the application of transcranial alternating current stimulation (tACS) in schizophrenia, inconsistent results have been reported. The purpose of this exploratory systematic review of RCTs was to evaluate tACS as an adjunct treatment for patients with schizophrenia based on its therapeutic effects, tolerability, and safety.

Methods

Our analysis included RCTs that evaluated adjunctive tACS' effectiveness, tolerability, and safety in schizophrenia patients. Three independent authors extracted data and synthesized it using RevMan 5.3 software.

Results

Three RCTs involving 76 patients with schizophrenia were encompassed in the analysis, with 40 participants receiving active tACS and 36 receiving sham tACS. Our study revealed a significant superiority of active tACS over sham tACS in improving total psychopathology (standardized mean difference [SMD] = -0.61, 95% confidence interval [CI]: -1.12, -0.10; I2 = 16%, p = 0.02) and negative psychopathology (SMD = -0.65, 95% CI: -1.11, -0.18; I2 = 0%, p = 0.007) in schizophrenia. The two groups, however, showed no significant differences in positive psychopathology, general psychopathology, or auditory hallucinations (all p > 0.05). Two RCTs examined the neurocognitive effects of tACS, yielding varied findings. Both groups demonstrated similar rates of discontinuation due to any reason and adverse events (all p > 0.05).

Conclusion

Adjunctive tACS is promising as a viable approach for mitigating total and negative psychopathology in individuals diagnosed with schizophrenia. However, to gain a more comprehensive understanding of tACS's therapeutic effects in schizophrenia, it is imperative to conduct extensive, meticulously planned, and well-documented RCTs.