The effect of physical exercise interventions on insomnia: A systematic review and meta-analysis.

6-10 % of Europeans suffer from chronic insomnia. They have a higher risk to develop mental and cardiovascular diseases. Treatment of insomnia primarily recommended by the European guideline is cognitive behavioral therapy for insomnia (CBT-I). A quarter of patients treated with CBT-I do not respond sufficiently. The objective of this paper is to examine the influence of exercise interventions on insomnia by conducting a systematic review and meta-analysis. A database search was conducted, including randomized controlled trials (RCT) in which participants had received a diagnosis of insomnia or experienced symptoms thereof. Exercise interventions had to meet the definition of the World Health Organization (WHO), and their implementation was reported according to the FITT (Frequency, Intensity, Time and Type) principle. There was an inactive control and subjective or objective sleep parameters as outcomes. Nineteen studies were included. Results showed a significant improvement for objective (standardized mean difference, SMD = 0.37; confidence interval, CI = [0.17; 0.57]) as well as subjective (SMD = 0.90; CI = [0.61; 1.19]) sleep parameters. Meta-regression showed that the effect increased with intensity of intervention, mean age of participants and percentage of females, but showed high heterogeneity across studies. These results suggest great potential for treating insomnia. Conducting larger trials is advisable to provide precise recommendations.

Digital cognitive behavioural therapy for insomnia reduces insomnia in nurses suffering from shift work disorder: A randomised-controlled pilot trial.

Insomnia is a primary symptom of shift work disorder, yet it remains undertreated. This randomised-controlled pilot trial examined the efficacy of a digital, guided cognitive behavioural therapy for insomnia adapted to shift work (SleepCare) in nurses with shift work disorder. The hypothesis was that SleepCare reduces insomnia severity compared with a waitlist control condition. A total of 46 unmedicated nurses suffering from shift work disorder with insomnia (age: 39.7 ± 12.1 years; 80.4% female) were randomised to the SleepCare group or the waitlist control group. The primary outcome measure was the Insomnia Severity Index. Other questionnaires on sleep, mental health and occupational functioning, sleep diary data and actigraphy data were analysed as secondary outcomes. Assessments were conducted before (T0), after the intervention/waitlist period (T1), and 6 months after treatment completion (T2). The SleepCare group showed a significant reduction in insomnia severity from T0 to T1 compared with the control condition (ß = -4.73, SE = 1.12, p < 0.001). Significant improvements were observed in sleepiness, dysfunctional beliefs about sleep, pre-sleep arousal, sleep effort, self-reported sleep efficiency and sleep onset latency. No significant effect was found in actigraphy data. Depressive and anxiety symptoms, cognitive irritation and work ability improved significantly. Overall, satisfaction and engagement with the intervention was high. SleepCare improved insomnia severity, sleep, mental health and occupational functioning. This is the first randomised-controlled trial investigating the efficacy of digital cognitive behavioural therapy for insomnia in a population suffering from shift work disorder with insomnia. Future research should further explore these effects with larger sample sizes and active control conditions.

Neurocognitive function as outcome and predictor for prefrontal transcranial direct current stimulation in major depressive disorder: an analysis from the DepressionDC trial.

Transcranial direct current stimulation (tDCS) of the prefrontal cortex might beneficially influence neurocognitive dysfunctions associated with major depressive disorder (MDD). However, previous studies of neurocognitive effects of tDCS have been inconclusive. In the current study, we analyzed longitudinal, neurocognitive data from 101 participants of a randomized controlled multicenter trial (DepressionDC), investigating the efficacy of bifrontal tDCS (2 mA, 30 min/d, for 6 weeks) in patients with MDD and insufficient response to selective serotonin reuptake inhibitors (SSRI). We assessed whether active tDCS compared to sham tDCS elicited beneficial effects across the domains of memory span, working memory, selective attention, sustained attention, executive process, and processing speed, assessed with a validated, digital test battery. Additionally, we explored whether baseline cognitive performance, as a proxy of fronto-parietal-network functioning, predicts the antidepressant effects of active tDCS versus sham tDCS. We found no statistically significant group differences in the change of neurocognitive performance between active and sham tDCS. Furthermore, baseline cognitive performance did not predict the clinical response to tDCS. Our findings indicate no advantage in neurocognition due to active tDCS in MDD. Additional research is required to systematically investigate the effects of tDCS protocols on neurocognitive performance in patients with MDD.

Interactions between insomnia, sleep duration and emotional processes: An ecological momentary assessment of longitudinal influences combining self-report and physiological measures.

Previous studies indicated that further investigation is needed to understand how insomnia disorder interacts with emotional processes. The present study is an ecological momentary assessment evaluating the link between emotional and sleep alterations in patients with insomnia. Physiological (heart rate and heart rate variability) and subjective (sleep and emotions) indices were observed for 5 days in patients with insomnia disorder (n = 97), good sleepers under self-imposed sleep restriction (n = 41), and good sleepers with usual amount of sleep (n = 45). We evaluated differences in emotion regulation strategies and in valence and variability of emotional experiences. Over 5 days, patients with insomnia showed increased sleep and emotional difficulties compared with both control groups. Independent from group allocation, days with more negative emotions were associated with higher sleep alterations. Longer wake episodes at night and higher diurnal heart rate were associated with increased variations in emotion experienced during the day. Only in patients with insomnia, use of adaptive emotion regulation strategies was associated with higher sleep efficiency. Our data showed that alterations in sleep and emotional processes are closely linked. A combination of strategies targeting both sleep and emotional processes appears promising in the prevention and treatment of insomnia disorder.

The importance and limitations of polysomnography in insomnia disorder-a critical appraisal.

The importance polysomnography (PSG) in the diagnosis and treatment process of insomnia disorder (ID) remains highly disputed. This review summarises the state of the science regarding PSG indications and findings in ID, and the indications to conduct PSG in ID as stated by relevant guidelines. It then highlights the most relevant questions regarding the topic, including the relevance of ID subtyping, to allow an individualised pharmacological or psychotherapeutic treatment approach.

Brain-derived neurotrophic factor genetic polymorphism rs6265 and creativity.

The protein brain-derived neurotrophic factor (BDNF) promotes neural plasticity of the central nervous system and plays an important role for learning and memory. A single nucleotide polymorphism (rs6265) at position 66 in the pro-region of the human BDNF gene, resulting in a substitution of the amino acid valine (val) with methionine (met), leads to attenuated BDNF secretion and has been associated with reduced neurocognitive function. Inhomogeneous results have been found regarding the effect of the BDNF genotype on behavior. We determined the BDNF genotype and performance on the Compound Remote Associate (CRA) task as a common measure of creativity in 76 healthy university students. In our main analyses, we did not find significant differences between met-carriers (n = 30) and non-met carriers (n = 46). In a secondary analysis, we found that met-carriers had a slower solution time (medium effect size) for items of medium difficulty. Our results suggest that met-carriers and non-met-carriers do not generally differ regarding their creativity, but non-met-carriers may have a certain advantage when it comes to moderately difficult problems. The wider literature suggests that both genetic variants come with advantages and disadvantages. Future research needs to sharpen our understanding of the disadvantages and, potentially, advantages met allele carriers may have.

Transcranial direct current stimulation as an additional treatment to selective serotonin reuptake inhibitors in adults with major depressive disorder in Germany (DepressionDC): a triple-blind, randomised, sham-controlled, multicentre trial.

BACKGROUND: Transcranial direct current stimulation (tDCS) has been proposed as a feasible treatment for major depressive disorder (MDD). However, meta-analytic evidence is heterogenous and data from multicentre trials are scarce. We aimed to assess the efficacy of tDCS versus sham stimulation as an additional treatment to a stable dose of selective serotonin reuptake inhibitors (SSRIs) in adults with MDD. METHODS: The DepressionDC trial was triple-blind, randomised, and sham-controlled and conducted at eight hospitals in Germany. Patients being treated at a participating hospital aged 18-65 years were eligible if they had a diagnosis of MDD, a score of at least 15 on the Hamilton Depression Rating Scale (21-item version), no response to at least one antidepressant trial in their current depressive episode, and treatment with an SSRI at a stable dose for at least 4 weeks before inclusion; the SSRI was continued at the same dose during stimulation. Patients were allocated (1:1) by fixed-blocked randomisation to receive either 30 min of 2 mA bifrontal tDCS every weekday for 4 weeks, then two tDCS sessions per week for 2 weeks, or sham stimulation at the same intervals. Randomisation was stratified by site and baseline Montgomery-Åsberg Depression Rating Scale (MADRS) score (ie, <31 or ≥31). Participants, raters, and operators were masked to treatment assignment. The primary outcome was change on the MADRS at week 6, analysed in the intention-to-treat population. Safety was assessed in all patients who received at least one treatment session. The trial was registered with ClinicalTrials.gov (NCT02530164). FINDINGS: Between Jan 19, 2016, and June 15, 2020, 3601 individuals were assessed for eligibility. 160 patients were included and randomly assigned to receive either active tDCS (n=83) or sham tDCS (n=77). Six patients withdrew consent and four patients were found to have been wrongly included, so data from 150 patients were analysed (89 [59%] were female and 61 [41%] were male). No intergroup difference was found in mean improvement on the MADRS at week 6 between the active tDCS group (n=77; -8·2, SD 7·2) and the sham tDCS group (n=73; -8·0, 9·3; difference 0·3 [95% CI -2·4 to 2·9]). Significantly more participants had one or more mild adverse events in the active tDCS group (50 [60%] of 83) than in the sham tDCS group (33 [43%] of 77; p=0·028). INTERPRETATION: Active tDCS was not superior to sham stimulation during a 6-week period. Our trial does not support the efficacy of tDCS as an additional treatment to SSRIs in adults with MDD. FUNDING: German Federal Ministry of Education and Research.

No alterations in potential indirect markers of locus coeruleus-norepinephrine function in insomnia disorder.

The norepinephrine locus coeruleus system (LC NE) represents a promising treatment target in patients with insomnia disorder (ID) due to its well understood links to arousal and sleep regulation. However, consistent markers of LC NE activity are lacking. This study measured three potential indirect markers of LC NE activity - REM sleep, P3 amplitude during an auditory oddball paradigm (as a marker of phasic LC activation), and baseline pupil diameter (as a marker of tonic LC activation). The parameters were then combined in a statistical model and tested to compare LC NE activity between 20 subjects with insomnia disorder (13 female; age 44.2 ± 15.1 year) and 20 healthy, good sleeping controls (GSC; 11 female; age 45.4 ± 11.6 year). No group differences regarding the primary outcome parameters were detected. Specifically, insomnia disorder did not display the hypothesised changes in markers of LC NE function. While increased LC NE function remains an interesting speculative pathway for hyperarousal in insomnia disorder, the investigated markers do not appear closely related to each other and fail to discriminate between insomnia disorder and good sleeping controls in these samples.

Presenting rose odor during learning, sleep and retrieval helps to improve memory consolidation: a real-life study.

Improving our learning abilities is important for numerous aspects of our life. Several studies found beneficial effects of presenting cues (odor or sounds) during learning and during sleep for memory performance. A recent study applying a real-life paradigm indicated that additional odor cueing during a Final Test can further increase this cueing effect. The present online study builds on these findings with the following questions: (1) Can we replicate beneficial memory effects of additional odor cueing during tests? (2) How many odor cueing learning sessions and odor cueing nights of sleep maximize the learning success? (3) Can odor cueing also reduce the amount of forgetting over time? 160 Participants learned 40 German Japanese word pairs in four groups with separate experimental conditions over three days. Group N received no odor during the whole study. Group LS received odor cueing during learning and sleep, group LT during learning and testing and group LST during learning, sleep and testing. Participants performed intermediate tests after each learning session plus three final tests 1, 7 and 28 days after the last learning session. Results: (1) Group LST learned 8.5% more vocabulary words than the other groups overall. (2) This odor cueing effect increased across the three days of cued learning. (3) We found no clear evidence for effects of odor cueing on the forgetting dynamics. Our findings support the notion of a beneficial effect of odor cueing. They further suggest to use at least 3 days and nights of odor cueing. Overall, this study indicates that there is an easy, efficient and economical way to enhance memory performance in daily life.

On the relationship between EEG spectral analysis and pre-sleep cognitive arousal in insomnia disorder: towards an integrated model of cognitive and cortical arousal.

According to the hyperarousal model, insomnia is characterised by increased arousal in the cortical, cognitive, and physiological domains. However, the interaction between these arousal domains is poorly understood. The present observational case-control study aimed to investigate cortical arousal during the night, pre-sleep cognitive arousal and the relationship between these two domains. A total of 109 patients with insomnia disorder (ID) and 109 age-and gender matched healthy controls were investigated on two sleep laboratory nights. Electroencephalographic (EEG) spectral power during non-rapid eye movement (NREM) and REM sleep was analysed as a measure of cortical arousal. In addition, patients completed the Pre-Sleep Arousal Scale (PSAS), which consists of two subscales, one for cognitive arousal (PSAS-CA) and one for self-reported somatic arousal (PSAS-SA). The relationship between the subscale scores and EEG spectral power was calculated by multi- and univariate analyses of variance. During NREM and REM sleep, patients with ID showed significantly increased spectral power in the EEG gamma band. In addition, patients with ID showed significantly increased scores on both subscales of the PSAS. The PSAS-CA score was significantly associated with increased NREM and REM gamma power, whereas PSAS-SA was associated with decreases in NREM and REM gamma power. Consistent with our hypothesis, patients with ID showed increased cortical and cognitive arousal. Moreover, there was an association between these two arousal domains, which may indicate that cortical arousal during the night is (at least in part) elicited by pre-sleep worry and rumination.

Comparative effectiveness of three versions of a stepped care model for insomnia differing in the amount of therapist support in internet-delivered treatment: study protocol for a pragmatic cluster randomised controlled trial (GET Sleep).

INTRODUCTION: It is unclear how internet-delivered cognitive-behavioural therapy for insomnia (CBT-I) can be integrated into healthcare systems, and little is known about the optimal level of therapist guidance. The aim of this study is to investigate three different versions of a stepped care model for insomnia (IG1, IG2, IG3) versus treatment as usual (TAU). IG1, IG2 and IG3 rely on treatment by general practitioners (GPs) in the entry level and differ in the amount of guidance by e-coaches in internet-delivered CBT-I. METHODS AND ANALYSIS: In this randomised controlled trial, 4268 patients meeting International Classification of Diseases, Tenth Revision (ICD-10) criteria for insomnia will be recruited. The study will use cluster randomisation of GPs with an allocation ratio of 3:3:3:1 (IG1, IG2, IG3, TAU). In step 1 of the stepped care model, GPs will deliver psychoeducational treatment; in step 2, an internet-delivered CBT-I programme will be used; in step 3, GPs will refer patients to specialised treatment. Outcomes will be collected at baseline, and 4 weeks, 12 weeks and 6 months after baseline assessment. The primary outcome is insomnia severity at 6 months. An economic evaluation will be conducted and qualitative interviews will be used to explore barriers and facilitators of the stepped care model. ETHICS AND DISSEMINATION: The study protocol was approved by the Ethics Committee of the Medical Centre-University of Freiburg. The results of the study will be published irrespective of the outcome. TRIAL REGISTRATION NUMBER: DRKS00021503.

Efficacy of Augmentation of Cognitive Behavioral Therapy With Transcranial Direct Current Stimulation for Depression: A Randomized Clinical Trial.

Importance: Major depressive disorder (MDD) affects approximately 10% of the population globally. Approximately 20% to 30% of patients with MDD do not sufficiently respond to standard treatment. Therefore, there is a need to develop more effective treatment strategies. Objective: To investigate whether the efficacy of cognitive behavioral therapy (CBT) for the treatment of MDD can be enhanced by concurrent transcranial direct current stimulation (tDCS). Design, Setting, and Participants: The double-blind, placebo-controlled randomized clinical trial PsychotherapyPlus was conducted at 6 university hospitals across Germany. Enrollment took place between June 2, 2016, and March 10, 2020; follow-up was completed August 27, 2020. Adults aged 20 to 65 years with a single or recurrent depressive episode were eligible. They were either not receiving medication or were receiving a stable regimen of antidepressant medication (selective serotonin reuptake inhibitor and/or mirtazapine). A total of 148 women and men underwent randomization: 53 individuals were assigned to CBT alone (group 0), 48 to CBT plus tDCS (group 1), and 47 to CBT plus sham-tDCS (group 2). Interventions: Participants attended a 6-week group intervention comprising 12 sessions of CBT. If assigned, tDCS was applied simultaneously. Active tDCS included stimulation with an intensity of 2 mA for 30 minutes (anode over F3, cathode over F4). Main Outcomes and Measures: The primary outcome was the change in Montgomery-Åsberg Depression Rating Scale (MADRS) score from baseline to posttreatment in the intention-to-treat sample. Scores of 0 to 6 indicate no depression; 7 to 19, mild depression; 20 to 34, moderate depression; and 34 and higher, severe depression. Results: A total of 148 patients (89 women, 59 men; mean [SD] age, 41.1 [13.7] years; MADRS score at baseline, 23.0 [6.4]) were randomized. Of these, 126 patients (mean [SD] age, 41.5 [14.0] years; MADRS score at baseline, 23.0 [6.3]) completed the study. In each of the intervention groups, intervention was able to reduce MADRS scores by a mean of 6.5 points (95% CI, 3.82-9.14 points). The Cohen d value was -0.90 (95% CI, -1.43 to -0.50), indicating a significant effect over time. However, there was no significant effect of group and no significant interaction of group × time, indicating the estimated additive effects were not statistically significant. There were no severe adverse events throughout the whole trial, and there were no significant differences of self-reported adverse effects during and after stimulation between groups 1 and 2. Conclusions and Relevance: Based on MADRS score changes, this trial did not indicate superior efficacy of tDCS-enhanced CBT compared with 2 CBT control conditions. The study confirmed that concurrent group CBT and tDCS is safe and feasible. However, additional research on mechanisms of neuromodulation to complement CBT and other behavioral interventions is needed. Trial Registration: ClinicalTrials.gov Identifier: NCT02633449.

Restless Legs Syndrome Prevalence and Clinical Correlates Among Psychiatric Inpatients: A Multicenter Study.

Background: There are only limited reports on the prevalence of restless legs syndrome (RLS) in patients with psychiatric disorders. The present study aimed to evaluate the prevalence and clinical correlates in psychiatric inpatients in Germany and Switzerland. Methods: This is a multicenter cross-sectional study of psychiatric inpatients with an age above 18 years that were diagnosed and evaluated face-to-face using the International RLS Study Group criteria (IRLSSG) and the International RLS severity scale (IRLS). In addition to sociodemographic and biometric data, sleep quality and mood were assessed using the Pittsburgh Sleep Quality Index (PSQI), the Insomnia Severity Index (ISI), the Epworth Sleepiness Scale (ESS), and the Patient Health Questionnaire (PHQ-9). In addition to univariate statistics used to describe and statistically analyze differences in variables of interest between patients with and without RLS, a logistic model was employed to identify predictors for the occurrence of RLS. Results: The prevalence of RLS in a sample of 317 psychiatric inpatients was 16.4%, and 76.9% of these were diagnosed with RLS for the first time. RLS severity was moderate to severe (IRLS ± SD: 20.3 ± 8.4). The prevalences in women (p = 0.0036) and in first-degree relatives with RLS (p = 0.0108) as well as the body mass index (BMI, p = 0.0161) were significantly higher among patients with RLS, while alcohol consumption was significantly lower in the RLS group. With the exception of atypical antipsychotics, treatment with psychotropic drugs was not associated with RLS symptoms. Regarding subjective sleep quality and mood, scores of the PSQI (p = 0.0007), ISI (p = 0.0003), and ESS (p = 0.0005) were higher in patients with RLS, while PHQ-9 scores were not different. A logistic regression analysis identified gender (OR 2.67; 95% CI [1.25; 5.72]), first-degree relatives with RLS (OR 3.29; 95% CI [1.11; 9.73], ESS score (OR 1.09; 95% CI [1.01; 1.17]), and rare alcohol consumption (OR 0.45; 95% CI [0.22; 0.94] as predictors for RLS. Conclusions: Clinically significant RLS had a high prevalence in psychiatric patients. RLS was associated with higher BMI, impaired sleep quality, and lower alcohol consumption. A systematic assessment of restless legs symptoms might contribute to improve the treatment of psychiatric patients.

Event-related potentials in insomnia reflect altered perception of sleep.

STUDY OBJECTIVES: Insomnia is defined by the subjective complaint of poor sleep as well as daytime impairments. Since polysomnography (PSG) typically shows only modest sleep impairment, some still unidentified property of sleep, not mirrored in PSG, may be modified in insomnia.One possible mechanistic hypothesis is that insomnia patients may be more sensitive to inevitably occurring internal or external stimuli during the night, causing brief sleep disruptions then perceived as wake time. METHODS: Auditory event-related potentials (ERP) to low intensity (50 dB SPL) synthesized guitar tones played continuously throughout two nights of polysomnographically registered sleep were obtained in fifty patients with insomnia disorder (ID, without comorbidities) and 50 age- and sex-matched good sleeper controls (GSC) for each sleep stage and NREM/REM cycle. Phasic and tonic REM were treated as separate stages. Latencies and amplitudes of components P1, N1 and P2 were measured and analyzed by multivariate repeated-measures ANCOVA including effects of group, night, cycle, and age. RESULTS: ID showed reduced P2 amplitudes relative to GSC specifically in phasic REM sleep. The same reduction also correlated with the amount of sleep misperception across groups. Independent component analysis showed a frontal negativity to contribute most to this group difference. CONCLUSIONS: The present finding can be interpreted as increased mismatch negativity (MMN) in ID, reflecting automated detection of change in the auditory system and a concomitant orienting response. Specifically phasic REM sleep appears to be vulnerable to sensory afferences in ID patients, possibly contributing to the perception of being awake. CLINICAL TRIAL INFORMATION: Short name "PERSLEEP 2," URL https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00008965, Registration DRKS00008965.

Sleep is more than rest for plasticity in the human cortex.

Sleep promotes adaptation of behavior and underlying neural plasticity in comparison to active wakefulness. However, the contribution of its two main characteristics, sleep-specific brain activity and reduced stimulus interference, remains unclear. We tested healthy humans on a texture discrimination task, a proxy for neural plasticity in primary visual cortex, in the morning and retested them in the afternoon after a period of daytime sleep, passive waking with maximally reduced interference, or active waking. Sleep restored performance in direct comparison to both passive and active waking, in which deterioration of performance across repeated within-day testing has been linked to synaptic saturation in the primary visual cortex. No difference between passive and active waking was observed. Control experiments indicated that deterioration across wakefulness was retinotopically specific to the trained visual field and not due to unspecific performance differences. The restorative effect of sleep correlated with time spent in NREM sleep and with electroencephalographic slow wave energy, which is thought to reflect renormalization of synaptic strength. The results indicate that sleep is more than a state of reduced stimulus interference, but that sleep-specific brain activity restores performance by actively refining cortical plasticity.

Transcranial direct current stimulation induces long-term potentiation-like plasticity in the human visual cortex.

Transcranial direct current stimulation (tDCS) is increasingly used as a form of noninvasive brain stimulation to treat psychiatric disorders; however, its mechanism of action remains unclear. Prolonged visual stimulation (PVS) can enhance evoked EEG potentials (visually evoked potentials, VEPs) and has been proposed as a tool to examine long-term potentiation (LTP) in humans. The objective of the current study was to induce and analyze VEP plasticity and examine whether tDCS could either modulate or mimic plasticity changes induced by PVS. Thirty-eight healthy participants received tDCS, PVS, either treatment combined or neither treatment, with stimulation sessions being separated by one week. One session consisted of a baseline VEP measurement, one stimulation block, and six test VEP measurements. For PVS, a checkerboard reversal pattern was presented, and for tDCS, a constant current of 1 mA was applied via each bioccipital anodal target electrode for 10 min (Fig. S1). Both stimulation types decreased amplitudes of C1 compared to no stimulation (F = 10.1; p = 0.002) and led to a significantly smaller increase (PVS) or even decrease (tDCS) in N1 compared to no stimulation (F = 4.7; p = 0.034). While all stimulation types increased P1 amplitudes, the linear mixed effects model did not detect a significant difference between active stimulation and no stimulation. Combined stimulation induced sustained plastic modulation of C1 and N1 but with a smaller effect size than what would be expected for an additive effect. The results demonstrate that tDCS can directly induce LTP-like plasticity in the human cortex and suggest a mechanism of action of tDCS relying on the restoration of dysregulated synaptic plasticity in psychiatric disorders such as depression and schizophrenia.

Offline Bi-Frontal Anodal Transcranial Direct Current Stimulation Decreases Total Sleep Time Without Disturbing Overnight Memory Consolidation.

OBJECTIVES: A proposed replay of memory traces between the hippocampus and frontal cortical brain areas during sleep is of high relevance for overnight memory consolidation. Recently, we demonstrated that bi-frontal anodal transcranial direct current stimulation (tDCS) prior to sleep increases waking EEG gamma power and decreases total sleep time during the night. It is unclear whether this effect on cortical excitability has an influence on overnight memory consolidation. We hypothesized that bi-frontal evening tDCS interferes with overnight memory consolidation with a polarity specific impairment following anodal tDCS. MATERIALS AND METHODS: Nineteen healthy participants underwent a within-subject, repeated-measures protocol in the sleep laboratory with bi-frontal tDCS applied prior to sleep according to the experimental protocol (anodal, cathodal, sham stimulation). Memory tasks for declarative and procedural memory were assessed prior to tDCS and on the following morning. RESULTS: No deterioration of overnight memory consolidation following evening offline bi-frontal tDCS could be detected. CONCLUSION(S): The application of tDCS can be considered safe regarding overnight memory consolidation and represents a promising treatment approach in conditions of decreased vigilance and arousal.

A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials Evaluating the Evidence Base of Melatonin, Light Exposure, Exercise, and Complementary and Alternative Medicine for Patients with Insomnia Disorder.

Insomnia is a prevalent disorder and it leads to relevant impairment in health-related quality of life. Recent clinical guidelines pointed out that Cognitive-Behavior Therapy for Insomnia (CBT-I) should be considered as first-line intervention. Nevertheless, many other interventions are commonly used by patients or have been proposed as effective for insomnia. These include melatonin, light exposure, exercise, and complementary and alternative medicine. Evaluation of comparable effectiveness of these interventions with first-line intervention for insomnia is however still lacking. We conducted a systematic review and network meta-analysis on the effects of these interventions. PubMed, PsycInfo, PsycArticles, MEDLINE, and CINAHL were systematically searched and 40 studies were included in the systematic review, while 36 were entered into the meta-analysis. Eight network meta-analyses were conducted. Findings support effectiveness of melatonin in improving sleep-onset difficulties and of meditative movement therapies for self-report sleep efficiency and severity of the insomnia disorder. Some support was observed for exercise, hypnotherapy, and transcranial magnetic resonance, but the number of studies for these interventions is still too small. None of the considered interventions received superior evidence to CBT-I, which should be more widely disseminated in primary care.