Digital mindfulness training and cognitive functions: A preregistered systematic review of neuropsychological findings

Traditional mindfulness interventions have been frequently reported to be effective in improving cognitive functions. In recent years, however, traditional programs are being increasingly replaced by technology-enabled mindfulness training programs. The aim of the present systematic review (PROSPERO ID: CRD42021289480) is to evaluate the research evidence on their effects on cognitive functions. Empirical training studies in the realm of digital mindfulness training that fulfilled the inclusion criteria led to 19 studies and 1654 participants being included in this review from among the papers searched in PubMed, Scopus, and Web of Knowledge. Results support previous assumptions on the potential of digital mindfulness training, with the most robust effect on attention control, followed by executive regulation, memory, cognitive flexibility, and other cognitive functions. However, the number of studies that did not find significant changes at least equaled, if not exceeded, the number of studies that found increases. The heterogeneity of identified studies prompted us to discuss several aspects in order to help the future development of digital applications.

Mindfulness induction and executive function after high-intensity interval training with and without mindful recovery intervals

OBJECTIVES

Determine the effect of incorporating mindfulness-based activities into the recovery intervals of high-intensity interval training (HIIT) on mindfulness induction and subsequent executive function performance.

DESIGNS

A within-subject crossover trial.

METHODS

Forty adults participated in two experimental conditions, including a 30-min bout of HIIT involving mindfulness recovery intervals (Mindful) and a 30-min bout of HIIT without mindfulness recovery intervals (Non-mindful), on two separate days in counterbalanced order. Before and after each condition, participants completed the flanker task, switch-flanker task, and n-back task to measure inhibitory control, cognitive flexibility, and working memory, respectively.

RESULTS

A higher level of mindfulness state was observed following the Mindful condition than the Non-mindful condition. Dispositional mindfulness was positively correlated with the level of the mindful state only during the Mindful condition but not the Non-mindful condition. The switch-flanker response accuracy was improved from the pretest to posttest during the Non-mindful condition but remained unchanged over time during the Mindful condition. Time-related improvements in the flanker and n-back task outcomes were observed for both the Mindful and Non-mindful conditions and did not differ between conditions.

CONCLUSION

Although incorporating mindfulness-based activities during the recovery intervals of HIIT successfully led to greater state-related mindfulness, such a heightened mindful state did not correspond with additional modulation in inhibitory control and working memory performance while attenuating HIIT-related positive changes in task performance requiring cognitive flexibility.

Effects of short mindful breathing meditations on executive functioning in two randomized controlled double-blinded experiments

While current models of mindfulness propose benefits to the executive functions of inhibition, updating and shifting through mindful breathing meditations, empirical findings on the effects of short mindful breathing meditations are inconclusive regarding their specificity and dose-response relations. Therefore, we compared short mindful breathing meditations (Experiment 1, 45 min over three sessions; Experiment 2, 80 min over four sessions) with relaxation trainings (progressive muscle relaxation; active control) and listening to podcasts (passive control) in two randomized controlled double-blinded trials. Reaction time tasks were used to assess the executive functions of updating (N-Back), inhibition (CPT-II), and shifting (Number-Letter Task). Results of both experiments suggest no mindfulness-specific improvements in executive functions. We conclude that effects following the first stages of mindfulness training may not be specific to the practice or too transient to be reliably measured in pre-post intervention designs. Implications for research in the field are discussed.

App-Based Mindfulness Meditation Training and an Audiobook Intervention Reduce Symptom Severity but Do Not Modify Backward Inhibition in Adolescent Obsessive-Compulsive Disorder: Evidence from an EEG Study

(1) Background: 1–2% of children and adolescents are affected by Obsessive-Compulsive Disorder (OCD). The rigid, repetitive features of OCD and an assumed disability to inhibit recent mental representations are assumed to have led to a paradoxical advantage in that the Backward Inhibition (BI) effect was recently found to be lower in adolescents with OCD as compared to healthy controls. It was hypothesized that app-based mindfulness meditation training could reduce the disability to inhibit recent mental representations and thus increase the BI-effect by adapting cognitive flexibility and inhibition abilities according to healthy controls. (2) Methods: 58 adolescents (10–19 years) with OCD were included in the final sample of this interviewer-blind, randomized controlled study. Participants were allocated to an intervention group (app-based mindfulness meditation training) or an (active) control group (app-based audiobook) for eight weeks. Symptom (CY-BOCS), behavioral (reaction times and mean accuracy), and neurophysiological changes (in EEG) of the BI-effect were analyzed in a pre-post design. (3) Results: The intervention and the control group showed an intervention effect (Reliable Change Index: 67%) with a significant symptom reduction. Contrary to the hypothesis, the BI-effect did not differ between pre vs. post app-based mindfulness meditation training. In addition, as expected the audiobook application showed no effects. Thus, we observed no intervention-specific differences with respect to behavioral (reaction times and mean accuracy) or with respect to neurophysiological (perceptual [P1], attentional [N1], conflict monitoring [N2] or updating and response selection [P3]) processes. However, in an exploratory approach, we revealed that the BI-effect decreased in participants who did not benefit from using an app, regardless of group. (4) Conclusions: Both listening to an app-based mindfulness meditation training and to an audiobook reduce symptom severity in adolescent OCD as measured by the CY-BOCS; however, they have no specific effect on BI. The extent of the baseline BI-effect might be considered as an intra-individual component to predict the benefit of both mindfulness meditation training and listening to an audiobook.

Event-related synchronization/desynchronization and functional neuroanatomical regions associated with fatigue effects on cognitive flexibility

Cognitive flexibility is an essential prerequisite for goal-directed behavior, and daily observations already show that it deteriorates when one is engaged in a task for a (too) long time. Yet, the neural mechanisms underlying such fatigability effect in cognitive flexibility are poorly understood. We examined how theta, alpha, and beta frequency event-related synchronization and desynchronization processes during cued memory-based task switching are modulated by time-on-task effects. We put special emphasis on the examination of functional neuroanatomical regions being associated with these modulations, using EEG beamforming. We show clear declines in task switching performance (increased switch costs) with time on task. For processes occurring before rule switching or repetition processes, we show that anticipatory attentional sampling and selection mechanisms associated with fronto-parietal structures are modulated by time-on-task effects but sensory areas (occipital cortex) also show fatigability-dependent modulations. After target stimulus presentation, the allocation of processing resources for response selection as reflected by theta-related activity in parietal cortices is compromised with time on task and similarly a concomitant increase in alpha and beta band-related attentional processing or gating mechanisms in frontal and occipital regions. Yet, considering the behavioral data showing an apparent decline in performance, this probably compensatory increase is still insufficient to allow reasonable performance. The same is likely the case for processes occurring before rule switching or repetition processes. Comparative analyses show that modulations of alpha band activity are as strongly modulated by fatigability as theta band activity. Implications of these findings for theoretical concepts on fatigability are discussed.NEW & NOTEWORTHY We examine the neurophysiological and functional neuroanatomical basis of fatigability in cognitive flexibility. We show that alpha and theta modulations in fronto-parietal and primary sensory areas are central for the understanding of fatigability effects in cognitive flexibility.

Task Switching and the Role of Motor Reprogramming in Parietal Structures

Human behaviour amazes with extraordinary flexibility and the underlying neural mechanisms have often been studied using task switching. Despite extensive research, the relative importance of "cognitive" and "motor" aspects during switching is unclear. In the current study we examine this question combining EEG analysis techniques and source localization to examine whether the selection of the response, or processes during the execution of the response, contribute most to switching effects. A clear dissociation was observed in the signal decomposition, since codes relating to motor aspects play a significant role in task switching and the scope of the switching costs. This was not the case for signals that denote reaction selection or decision processes that respond to selection or basic stimulus processing codes. On a functional neuroanatomical level, these modulations in motor processes showed a clear temporal sequence in that motor codes are processed primarily in superior parietal regions (Brodman area 7) and only then in premotor regions (Brodman area 6). The observed modulations may reflect motor reprogramming processes. The study shows how EEG signal analysis in combination with brain mapping methods can inform debates on theories of human cognitive flexibility.