Can Brain and Nerve Stimulation Ease Stress and Improve Sleep?

How many participants were ultimately included in the study after screening?

A total of 100 participants (50 females and 50 males, mean age of 37.2 years) were included in the study.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

What was the stimulation target and current intensity used for the tDCS groups?

The target was the dorsolateral prefrontal cortex (DLPFC) using an anodal current of 2 mA.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

What was the stimulation site and frequency used for the taVNS groups?

The stimulation was applied to the left ear at a frequency of 20 Hz.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

How many sessions of treatment did the participants receive, and what was the duration of each session?

Participants received 5 sessions of treatment, and each session lasted for 20 minutes.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

Which specific scale was used in this study to evaluate stress symptoms in adults?

Lipp's Inventory of Stress Symptoms for Adults (LSSI) was used.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

What instrument was utilized to measure the participants' perceived stress?

The Perceived Stress Scale (PSS-10) was utilized.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

Which questionnaire was selected to evaluate the participants' sleep quality?

The Pittsburgh Sleep Quality Index (PSQI) was selected.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

At what three timepoints were the participants' stress and sleep quality evaluated?

Evaluations occurred at baseline (T0), post-intervention (T1), and at a 4-week follow-up (T2).

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

Which statistical tests were used to evaluate the normality of the data sets?

The Kolmogorov-Smirnov test was used initially, and the Shapiro-Wilk test was also reported in the results.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

Which statistical tests were used for intergroup comparisons if the data did not meet the normality assumption?

The Kruskal-Wallis test (for multiple groups) or the Mann-Whitney U test (for two groups) were used.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

What was the effect of active anodal tDCS on stress levels (LSSI) from baseline (T0) to post-intervention (T1)?

Active anodal tDCS led to a significant reduction in stress levels at T1, and this reduction was sustained at the 4-week follow-up (T2).

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

How did stress levels (LSSI) change immediately post-treatment (T1) in the sham tDCS group?

The sham group showed an initial increase in stress levels at T1 compared to T0, which then significantly decreased by T2.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

What did the PSS-10 analysis reveal about the active anodal tDCS group's perceived stress?

Participants in the active group showed a significant reduction in perceived stress, particularly noticeable from T1 to T2.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

How did active tDCS affect sleep quality compared to sham tDCS?

Active tDCS led to a gradual, significant improvement in sleep quality, whereas the sham group showed no notable improvement.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

What was the primary finding regarding active taVNS on stress levels (LSSI) between T1 and T0?

Active taVNS led to a significant decrease in stress levels compared to the sham group, indicating gradual stress regulation.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

What change was observed in perceived stress (PSS-10) for the active taVNS group over time?

Active taVNS led to a notable, gradual improvement in perceived stress levels over time, especially from T1 to T2.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

What was the outcome of active taVNS on sleep quality (PSQI) compared to sham?

Active taVNS significantly improved sleep quality over time, showing clear superiority over the sham group.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

How did the effect sizes of tDCS and taVNS compare regarding stress reduction and sleep quality improvement?

tDCS demonstrated larger effect sizes (Cohen's d = 0.72–0.80) than taVNS (Cohen's d = 0.68–0.75).

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

How did the pattern of improvement over time differ between tDCS and taVNS?

tDCS showed larger immediate/short-term effects, whereas taVNS showed a more gradual but sustained improvement in stress regulation over time.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

Why did one participant drop out of the active taVNS group during the study?

The participant experienced a severe headache after receiving three sessions, which led to withdrawal.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

How did the study design attempt to minimize the placebo effect?

By using double-blinding (where neither participants nor researchers knew the assignment) and identical electrode activation protocols for active and sham setups.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

What does the lack of significant differences between T0 and T1 for some measures suggest about these neuromodulation techniques?

It suggests that immediate changes should not be expected after initial sessions, and multiple sessions are required to produce cumulative neural and neurochemical alterations.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified

What were two key methodological limitations of this study noted by the authors?

The study was limited by a relatively small sample size (which limits generalizability) and a short-term follow-up duration.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI

What types of objective physiological measures did the authors suggest adding to future studies to strengthen findings?

They suggested assessing cortisol levels to measure physiological stress and utilizing actigraphy to objectively evaluate sleep.

Source: Effects of multisession prefrontal cortex tDCS or taVNS on stress, perceived stress and sleep quality: a double-blind, randomized controlled study · DOI · quote verified