[Disturbances of slow-wave sleep and psychiatric disorders]

Different regulative effects of high- and low-frequency external trigeminal nerve stimulation (eTNS) on sleep activity: Preliminary study

STUDY OBJECTIVE

With the growing prominence of peripheral nerve stimulation technology, the clinical applications and potential neurophysiological mechanisms of external trigeminal nerve stimulation (eTNS) have garnered increasing attention. Despite its status as the sole neuromodulation method commonly employed in sleep, no studies have explored the effects of eTNS at varying frequencies on sleep activities. This study aims to investigate the regulatory effects of high-frequency and low-frequency eTNS on sleep activities using polysomnography.

METHODS

In this within-subjects experiment, 20 participants underwent a night of adaptation sleep, followed by 8-h sessions of sham, 120Hz-, and 2Hz-eTNS interventions in a randomized order in the sleep laboratory, with polysomnographic signals collected throughout.

RESULTS

The results indicated that 120Hz-eTNS significantly improved sleep efficiency, increased N2 sleep proportion, and reduced sleep latency, without significantly affecting sleep stage transition probabilities, sleep duration, or sleep-specific wave activities. Conversely, while 2Hz-eTNS did not impact sleep efficiency or latency, it increased the proportion of N3 sleep, stabilizes N3 sleep, and enhanced the survival probability of N3 and REM sleep duration. Additionally, it increases the density of slow oscillations (SOs), improved the coupling ratio of SO-spindles, and enhanced coupling timing accuracy.

CONCLUSIONS

These findings suggest that eTNS during sleep can indeed modulate sleep activities, with different frequencies exerting distinct regulatory effects. This may hold significant value for advancing the clinical application and efficacy of eTNS.

Changes in sleep architecture in German Armed Forces personnel with posttraumatic stress disorder compared with depressed and healthy control subjects

BACKGROUND

This study compares the sleep architecture of patients with posttraumatic stress disorder (PTSD) with that of both patients with depression and subjects with no mental disorder.

METHOD

45 German armed forces personnel with PTSD, 72 German armed forces personnel with depression and 24 healthy control subjects underwent 24-hour polysomnography. The effects of group membership, medication and the statistical interaction of group and medication were analysed for the following variables: sleep onset latency, REM sleep latency, slow-wave sleep and REM sleep percentages.

RESULTS

Sleep onset latency was significantly prolonged in both the PTSD and the depression group. Moreover, psychotropic medication was associated with significantly prolonged REM sleep latency.

CONCLUSION

The impact on sleep onset latency is of special clinical relevance in that according to preliminary studies, it is of major importance for subjective sleep quality. In contrast to the other parameters, an increase in sleep onset latency results in a subjective reduction in sleep quality which can lead to hyperarousal and increased preoccupation with sleep, which in turn may lead to dysfunctional sleep patterns.

CBT-I and HT-I group therapy for adults with insomnia in comparison to those with insomnia and comorbid depression - a pilot study

PURPOSE

The aim of this study was to examine the effectiveness of a combined cognitive-behavioral therapy for insomnia (CBT-I) and hypnotherapy for insomnia (HT-I) program for insomnia patients with or without additional depression regarding depressive symptoms and various sleep parameters.

PATIENTS AND METHODS

A sample of 63 patients suffering from insomnia received a six-session sleep intervention, which combined cognitive-behavioral and hypnotherapeutical elements. Due to violating exclusion criteria, data of 37 patients were analyzed. Ten patients had insomnia comorbid with depression, whereas 27 patients had insomnia only. Sleep diaries were implemented to measure various sleep parameters, whereas depressive symptomatology was assessed with the anxiety and depression scale and Symptom-Checklist-90-R at baseline, before and after the intervention, as well as at 3-months follow-up.

RESULTS

Depressive symptoms decreased from pre to post measurement and follow-up for patients with insomnia comorbid with depression, whereas scores of patients with only insomnia remained relatively on a low level. Both groups showed a significant increase of sleep efficiency and a significant decrease of the duration of wake after sleep onset. However, only patients with insomnia and depression revealed a significant reduction of sleep-onset latency and a higher level of regeneration. Nondepressive insomniacs, on the other hand, showed a significant increase of performance from post measurement to follow-up. For both groups, no change over time was found for number of wake after sleep onset, total sleep time, mood in the morning and evening.

CONCLUSION

Combining CBT-I and HT-I is effective in reducing depressive symptoms and improving sleep. Therefore, nonresponders to other forms of therapy, eg, pharmacological, interpersonal, or cognitive-behavioral therapy, might benefit from the combined CBT-I/HT-I intervention.

Long-Term Single and Joint Effects of Excessive Daytime Napping on the HOMA-IR Index and Glycosylated Hemoglobin: A Prospective Cohort Study

This prospective cohort study was conducted to assess the duration of daytime napping and its effect combined with night sleep deprivation on the risk of developing high HOMA-IR (homeostasis model assessment of insulin resistance) index and disadvantageous changes in glycosylated hemoglobin (HbA1c) levels.A total of 5845 diabetes-free subjects (2736 women and 3109 men), 30 to 65 years of age, were targeted for this cohort study since 2008. Multiple adjusted Cox regression models were performed to evaluate the single and joint effects of daytime napping on the risk of an elevated HbA1c level and high HOMA-IR index.After an average of 4.5 years of follow-up, >30 minutes of daytime napping was significantly associated with an increased risk of an elevated HbA1c level (>6.5%) in men and women (all P trend < 0.05). Hazard ratios (HRs) for an HbA1c level between 5.7% and 6.4% were also significant in the entire cohort and women, but nonsignificant in men. HRs (95% confidence interval, CIs) for the high HOMA-IR index in the entire cohort, men, and women were 1.33 (1.10-1.62), 1.46 (1.08-1.98), and 1.47 (1.12-1.91), respectively. The combination of sleep deprivation with no naps or >30 minutes napping and the combination of no sleep deprivation with >30 minutes daytime napping were all associated with an HbA1c level >6.5% (HR = 2.08, 95% CI = 1.24-3.51; HR = 4.00, 95% CI = 2.03-7.90; and HR = 2.05, 95% CI = 1.29-3.27, respectively). No sleep deprivation combined with >30 minutes daytime napping correlated with a high risk of an HbA1c level between 5.7% and 6.4% and high HOMA-IR index (HR = 2.12, 95% CI = 1.48-3.02; and HR = 1.35, 95% CI = 1.10-1.65, respectively).Daytime napping >30 minutes was associated with a high risk of an elevated HbA1c level and high HOMA-IR index. No sleep deprivation combined with napping >30 minutes carries a risk of abnormal glucose metabolism. Sleep deprivation combined with brief daytime napping <30 minutes was not associated with a risk for an elevated HbA1c level and high HOMA-IR index.

Human biomarkers of rapid antidepressant effects

Mood disorders such as major depressive disorder and bipolar disorder--and their consequent effects on the individual and society--are among the most disabling and costly of all medical illnesses. Although a number of antidepressant treatments are available in clinical practice, many patients still undergo multiple and lengthy medication trials before experiencing relief of symptoms. Therefore a tremendous need exists to improve current treatment options and to facilitate more rapid, successful treatment in patients suffering from the deleterious neurobiological effects of ongoing depression. Toward that end, ongoing research is exploring the identification of biomarkers that might be involved in prevention, diagnosis, treatment response, severity, or prognosis of depression. Biomarkers evaluating treatment response will be the focus of this review, given the importance of providing relief to patients in a more expedient and systematic manner. A novel approach to developing such biomarkers of response would incorporate interventions with a rapid onset of action--such as sleep deprivation or intravenous drugs (e.g., ketamine or scopolamine). This alternative translational model for new treatments in psychiatry would facilitate shorter studies, improve feasibility, and increase higher compound throughput testing for these devastating disorders.

Beyond fatigue: Assessing variables associated with sleep problems and use of sleep medications in multiple sclerosis

Background:

Recent research indicates that sleep disturbances are common in persons with multiple sclerosis (MS), though research to date has primarily focused on the relationship between fatigue and sleep. In order to improve treatment of sleep disorders in MS, a better understanding of other factors that contribute to MS sleep disturbance and use of sleep medications in this population is needed.

Methods:

Individuals with MS (N = 473) involved in an ongoing self-report survey study were asked to report on use of over-the-counter and prescription sleep medications. Participants completed the Medical Outcomes Study Sleep (MOSS) scale and other common self-report symptom measures. Multiple regression was used to evaluate factors associated with sleep problems and descriptive statistics were generated to examine use of sleep medications.

Results:

The mean score on the MOSS scale was 35.9 (standard deviation, 20.2) and 46.8% of the sample had moderate or severe sleep problems. The majority of participants did not use over-the-counter (78%) or prescription (70%) sleep medications. In a regression model variables statistically significantly associated with sleep problems included depression, nighttime leg cramps, younger age, pain, female sex, fatigue, shorter duration of MS, and nocturia. The model explained 45% of the variance in sleep problems. Of the variance explained, depression accounted for the majority of variance in sleep problems (33%), with other variables explaining significantly less variance.

Conclusions:

Regression results indicate that fatigue may play a minor role in sleep disturbance in MS and that clinicians should consider the interrelationship between depression and sleep problems when treating either symptom in this population. More research is needed to explore the possibility of under-treatment of sleep disorders in MS and examine the potential effectiveness of nonpharmaceutical treatment options.