Clinical Hypnosis for Procedural Pain and Distress in Children: A Scoping Review.

OBJECTIVE: Pain and distress are common in children undergoing medical procedures, exposing them to acute and chronic biopsychosocial impairments if inadequately treated. Clinical hypnosis has emerged as a potentially beneficial treatment for children's procedural pain and distress due to evidence of effectiveness and potential superiority to other psychological interventions. However, systematic reviews of clinical hypnosis for children's procedural pain and distress have been predominantly conducted in children undergoing oncology and needle procedures and are lacking in broader pediatric contexts. This scoping review maps the evidence of clinical hypnosis for children's procedural pain and distress across broad pediatric contexts while highlighting knowledge gaps and areas requiring further investigation. METHODS: Published databases (PubMed, Cochrane Library, PsycINFO, Embase, CINAHL, Scopus, and Web of Science) and grey literature were searched in addition to hand-searching reference lists and key journals (up to May 2022). Two independent reviewers screened the titles and abstracts of search results followed by a full-text review against eligibility criteria. Articles were included if they involved a clinical hypnosis intervention comprising an induction followed by therapeutic suggestions for pain and distress in children undergoing medical procedures. This review followed the Arksey and O'Malley (2005) methodology and incorporated additional scoping review recommendations by the Joanna Briggs Institute and Preferred Reporting Items for Systematic Reviews and Meta-Analyses. RESULTS: A total of 38 eligible studies involving 2,205 children were included after 4,775 articles were screened. Research on clinical hypnosis for children's procedural pain and distress was marked by a lack of fidelity measures and qualitative data as well as by inadequate intervention reporting and high attrition rates. Evidence regarding the safety of clinical hypnosis, pain unpleasantness outcomes, factors influencing outcomes, as well as barriers and facilitators to implementing hypnosis and study procedures was also lacking. Clinical hypnosis has potential benefits for children's procedural pain and distress based on evidence of superiority to control conditions and nonpharmacological interventions (e.g., distraction, acupressure) with moderate to large effect sizes as reported in 76% of studies. However, heterogeneous interventions, contexts, study designs, and populations were identified, and the certainty of the evidence was not evaluated. CONCLUSIONS: The review suggests potential benefits of clinical hypnosis for children's procedural pain and distress and thus provides a precursor for further systematic reviews and trials investigating the effectiveness of clinical hypnosis. The review also indicates the need to further explore the feasibility, acceptability, implementation, and safety of clinical hypnosis in children undergoing painful procedures. Based on the review, researchers implementing clinical hypnosis should adequately report interventions or use treatment manuals, follow recommended research guidelines, and assess the fidelity of intervention delivery to promote replicating and comparing interventions. The review also highlights common methodological shortcomings of published trials to avoid, such as the lack of implementation frameworks, small sample sizes, inadequate reporting of standard care or control conditions, and limited evidence on pain unpleasantness outcomes.

Introspection confidence predicts EEG decoding of self-generated thoughts and meta-awareness.

The neurophysiological bases of mind wandering (MW)-an experiential state wherein attention is disengaged from the external environment in favour of internal thoughts-and state meta-awareness are poorly understood. In parallel, the relationship between introspection confidence in experiential state judgements and neural representations remains unclear. Here, we recorded EEG while participants completed a listening task within which they made experiential state judgements and rated their confidence. Alpha power was reliably greater during MW episodes, with unaware MW further associated with greater delta and theta power. Multivariate pattern classification analysis revealed that MW and meta-awareness can be decoded from the distribution of power in these three frequency bands. Critically, we show that individual decoding accuracies positively correlate with introspection confidence. Our results reaffirm the role of alpha oscillations in MW, implicate lower frequencies in meta-awareness, and are consistent with the proposal that introspection confidence indexes neurophysiological discriminability of representational states.

Taxometric evidence for a dimensional latent structure of hypnotic suggestibility.

Hypnotic suggestibility denotes a capacity to respond to direct verbal suggestions in an involuntary manner. Most research on responsiveness to hypnotic suggestions has focused on highly suggestible individuals but it remains unclear whether these individuals constitute a discrete subgroup (taxon) characterized by a distinct mode of responding from the remainder of the population or whether hypnotic suggestibility is better modelled as a dimensional ability. In this study, we applied taxometric analysis, a method for distinguishing between dimensional and categorical models of a psychological ability, to behavioural and involuntariness subscale scores of the Harvard Group Scale of Hypnotic Susceptibility Scale: Form A (HGSHS:A) in a non-clinical sample (N = 584). Analyses of HGSHS:A subscale scores with different a priori taxon base rates yielded consistent evidence for a dimensional structure. These results suggest that hypnotic suggestibility is dimensional and have implications for current understanding of individual differences in responsiveness to direct verbal suggestions.

The chemical induction of synaesthesia.

OBJECTIVE: Preliminary research suggests that experiences resembling synaesthesia are frequently reported under the influence of a diverse range of chemical substances although the incidence, chemical specificity, and characteristics of these effects are poorly understood. METHODS: Here we surveyed recreational drug users and self-reported developmental synaesthetes regarding their use of 28 psychoactive drugs from 12 different drug classes and whether they had experienced synaesthesia under the influence of these substances. RESULTS: The drug class of tryptamines exhibited the highest incidence rates of drug-induced synaesthesia in controls and induction rates of novel forms of synaesthesia in developmental synaesthetes. Induction incidence rates in controls were strongly correlated with the corresponding induction and enhancement rates in developmental synaesthetes. In addition, the use of lysergic acid diethylamide (LSD) was the strongest predictor of drug-induced synaesthesia in both controls and developmental synaesthetes. Clear evidence was observed for a clustering of synaesthesia-induction rates as a function of drug class in both groups, denoting non-random incidence rates within drug classes. Sound-colour synaesthesia was the most commonly observed type of induced synaesthesia. Further analyses suggest the presence of synaesthesia-prone individuals, who were more likely to experience drug-induced synaesthesia with multiple drugs. CONCLUSIONS: These data corroborate the hypothesized link between drug-induced synaesthesia and serotoninergic activity, but also suggest the possibility of alternative neurochemical pathways involved in the induction of synaesthesia. They further imply that the induction and modulation of synaesthesia in controls and developmental synaesthetes share overlapping mechanisms and that certain individuals may be more susceptible to experiencing induced synaesthesia with different drugs.

Examining the effect of Libet clock stimulus parameters on temporal binding.

Temporal binding refers to the subjective temporal compression between actions and their outcomes. It is widely used as an implicit measure of sense of agency, that is, the experience of controlling our actions and their consequences. One of the most common measures of temporal binding is the paradigm developed by Haggard, Clark and Kalogeras (2002) based on the Libet clock stimulus. Although widely used, it is not clear how sensitive the temporal binding effect is to the parameters of the clock stimulus. Here, we present five experiments examining the effects of clock speed, number of clock markings and length of the clock hand on binding. Our results show that the magnitude of temporal binding increases with faster clock speeds, whereas clock markings and clock hand length do not significantly influence temporal binding. We discuss the implications of these results.

Symptom variability in depersonalization-derealization disorder: A latent profile analysis.

OBJECTIVE: Depersonalization-derealization disorder (DDD) is characterized by diverse symptomatology overlapping with anxiety and dissociative disorders, but the sources of this variability are poorly understood. This study aims to determine whether symptom heterogeneity is attributable to the presence of latent subgroups. METHOD: We applied latent profile analysis to psychometric measures of anxiety, depersonalization-derealization, and dissociation in 303 DDD patients. RESULTS: The analysis yielded evidence for five discrete subgroups: three of varying severity levels and two moderate-to-severe classes characterized by differential dissociative symptoms. The five classes reliably differed on several nondissociative symptoms, comorbidities, and factors precipitating their diagnosis but did not significantly differ in other symptoms including anxiety. CONCLUSION: These results suggest the presence of three distinct DDD subtypes in the upper severity range that are distinguished by differential expression of detachment and compartmentalization symptoms. Further elucidation of these subtypes has potential implications for the etiology, mechanisms, and treatment of DDD.

Direct Verbal Suggestibility as a Predictor of Placebo Hypoalgesia Responsiveness.

OBJECTIVE: Reliably identifying good placebo responders has pronounced implications for basic research on, and clinical applications of, the placebo response. Multiple studies point to direct verbal suggestibility as a potentially valuable predictor of individual differences in placebo responsiveness, but previous research has produced conflicting results on this association. METHODS: In two double-blind studies, we examined whether behavioral direct verbal suggestibility measures involving a correction for compliance would be associated with individual differences in responsiveness to conditioned and unconditioned placebo hypoalgesia using an established placebo analgesia paradigm. In study 1 (n = 57; mean [standard deviation] age = 23.7 [8.1] years; 77% women), we used behavioral hypnotic suggestibility as a predictor of placebo hypoalgesia induced through conditioning and verbal suggestion, whereas in study 2 (n = 78; mean [standard deviation] = 26.1 [7.4] years; 65% women), we measured nonhypnotic suggestibility and placebo hypoalgesia induced through verbal suggestion without conditioning. RESULTS: In study 1, the placebo hypoalgesia procedure yielded a moderate placebo response (g = 0.63 [95% confidence interval = 0.32 to 0.97]), but the response magnitude did not significantly correlate with hypnotic suggestibility (rs = 0.11 [-0.17 to 0.37]). In study 2, the placebo procedure did not yield a significant placebo response across the full sample (g = 0.11 [-0.11 to 0.33]), but the magnitude of individual placebo responsiveness significantly correlated with nonhypnotic suggestibility (rs = 0.27 [0.03 to 0.48]). CONCLUSIONS: These results suggest that the extent to which direct verbal suggestibility captures variability in placebo responsiveness depends on the use of conditioning and highlights the utility of suggestibility as a potential contributing factor to placebo responding when placebo hypoalgesia is induced through verbal suggestions.

Suggestibility in functional neurological disorder: a meta-analysis.

OBJECTIVE: Responsiveness to direct verbal suggestions (suggestibility) has long been hypothesised to represent a predisposing factor for functional neurological disorder (FND) but previous research has yielded conflicting results. The aim of this study was to quantitatively evaluate whether patients with FND display elevated suggestibility relative to controls via meta-analysis. METHODS: Four electronic databases were searched in November 2019, with the search updated in April 2020, for original studies assessing suggestibility using standardised behavioural scales or suggestive symptom induction protocols in patients with FND (including somatisation disorder) and controls. The meta-analysis followed Cochrane, Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-analyses Of Observational Studies in Epidemiology (MOOSE) guidelines. Data extraction and study quality coding were performed by two independent reviewers. Standardised suggestibility scores and responsiveness to symptom induction protocols were used to calculate standardised mean differences (SMDs) between groups. RESULTS: Of 26 643 search results, 19 articles presenting 11 standardised suggestibility data sets (FND: n=316; control: n=360) and 11 symptom suggestibility data sets (FND: n=1285; control: n=1409) were included in random-effect meta-analyses. Meta-analyses revealed that patients with FND displayed greater suggestibility than controls on standardised behavioural scales (SMD, 0.48 (95% C, 0.15 to 0.81)) and greater responsiveness to suggestive symptom induction (SMD, 1.39 (95% CI 0.92 to 1.86)). Moderation analyses presented mixed evidence regarding the extent to which effect sizes covaried with methodological differences across studies. No evidence of publication bias was found. CONCLUSIONS: These results corroborate the hypothesis that FND is characterised by heightened responsiveness to verbal suggestion. Atypical suggestibility may confer risk for FND and be a cognitive marker that can inform diagnosis and treatment of this condition.

Using adaptive psychophysics to identify the neural network reset time in subsecond interval timing.

State-dependent network models of sub-second interval timing propose that duration is encoded in states of neuronal populations that need to reset prior to a novel timing operation to maintain optimal timing performance. Previous research has shown that the approximate boundary of this reset interval can be inferred by varying the inter-stimulus interval between two to-be-timed intervals. However, the estimated boundary of this reset interval is broad (250-500 ms) and remains under-specified with implications for the characteristics of state-dependent network dynamics sub-serving interval timing. Here, we probed the interval specificity of this reset boundary by manipulating the inter-stimulus interval between standard and comparison intervals in two sub-second auditory duration discrimination tasks (100 and 200 ms) and a control (pitch) discrimination task using adaptive psychophysics. We found that discrimination thresholds improved with the introduction of a 333 ms inter-stimulus interval relative to a 250 ms inter-stimulus interval in both duration discrimination tasks, but not in the control task. This effect corroborates previous findings of a breakpoint in the discrimination performance for sub-second stimulus interval pairs as a function of an incremental inter-stimulus delay but more precisely localizes the minimal inter-stimulus delay range. These results suggest that state-dependent networks sub-serving sub-second timing require approximately 250-333 ms for the network to reset to maintain optimal interval timing.

Towards a neurocognitive approach to dance movement therapy for mental health: A systematic review.

Dance movement therapy (DMT) has become an increasingly recognized and used treatment, though primarily used to target psychological and physical well-being in individuals with physical, medical or neurological illnesses. To contribute to the relative lack of literature within the field of DMT for clinical mental health disorders, using a narrative synthesis, we review the scope of recent, controlled studies of DMT in samples with different psychiatric disorders including depression, schizophrenia, autism and somatoform disorder. A systematic search of electronic databases (PubMed, Science Direct, World of Science and Clinicaltrials.gov) was conducted to identify studies examining the effects of DMT in psychiatric populations. Fifteen studies were eligible for inclusion. After reviewing the principal results of the studies, we highlight strengths and weaknesses of this treatment approach and examine the potential efficacy of using bodily movements as a tool to reduce symptoms. We conclude by placing DMT within the context of contemporary cognitive neuroscience research, drawing out implications of such an orientation for future research and discussing potential mechanisms by which DMT might reduce psychiatric symptoms. DMT has clear potential as a treatment for a range of conditions and symptoms, and thus, further research on its utility is warranted.

Anomalous experiences are more prevalent among highly suggestible individuals who are also highly dissociative.

Introduction: Predictive coding models propose that high hypnotic suggestibility confers a predisposition to hallucinate due to an elevated propensity to weight perceptual beliefs (priors) over sensory evidence. Multiple lines of research corroborate this prediction and demonstrate a link between hypnotic suggestibility and proneness to anomalous perceptual states. However, such effects might be moderated by dissociative tendencies, which seem to account for heterogeneity in high hypnotic suggestibility. We tested the prediction that the prevalence of anomalous experiences would be greater among highly suggestible individuals who are also highly dissociative.Methods: We compared high and low dissociative highly suggestible participants and low suggestible controls on multiple psychometric measures of anomalous experiences.Results: High dissociative highly suggestible participants reliably reported greater anomalous experiences than low dissociative highly suggestible participants and low suggestible controls, who did not significantly differ from each other.Conclusions: These results suggest a greater predisposition to experience anomalous perceptual states among high dissociative highly suggestible individuals.

Trauma and anxious attachment influence the relationship between suggestibility and dissociation: a moderated-moderation analysis.

INTRODUCTION: Hypnotic suggestibility is elevated in the dissociative disorders but the relationship between dissociative tendencies and suggestibility in the general population seems to be constrained by additional factors. The diathesis-stress (DS) model stipulates that suggestibility interacts with trauma exposure to augment the propensity for dissociative states whereas the dual pathway to suggestibility (DPS) model proposes two developmental routes involving either dissociation preceded by trauma, or a healthy cognitive profile characterised by superior imagination. METHODS: This study sought to discriminate between these partially competing accounts and further considered the moderating role of anxious attachment. 209 participants completed psychometric measures of dissociative tendencies, trauma, and attachment, and a behavioural measure of suggestibility. RESULTS: In support of the DS model, trauma moderated the relationship between suggestibility and dissociation and, as predicted by the DPS model, dissociation moderated the relationship between trauma and suggestibility. Anxious attachment additionally moderated both effects. Model comparisons indicated that the DS model consistently provided a superior fit to the data. Further analyses showed that secure attachment independently predicted suggestibility, thereby supporting the non-dissociative pathway in the DPS model. CONCLUSIONS: These results suggest that high suggestibility confers vulnerability to dissociative states in individuals exposed to trauma and displaying an anxious attachment style.

Phosphene Perception Relates to Visual Cortex Glutamate Levels and Covaries with Atypical Visuospatial Awareness.

Phosphenes are illusory visual percepts produced by the application of transcranial magnetic stimulation to occipital cortex. Phosphene thresholds, the minimum stimulation intensity required to reliably produce phosphenes, are widely used as an index of cortical excitability. However, the neural basis of phosphene thresholds and their relationship to individual differences in visual cognition are poorly understood. Here, we investigated the neurochemical basis of phosphene perception by measuring basal GABA and glutamate levels in primary visual cortex using magnetic resonance spectroscopy. We further examined whether phosphene thresholds would relate to the visuospatial phenomenology of grapheme-color synesthesia, a condition characterized by atypical binding and involuntary color photisms. Phosphene thresholds negatively correlated with glutamate concentrations in visual cortex, with lower thresholds associated with elevated glutamate. This relationship was robust, present in both controls and synesthetes, and exhibited neurochemical, topographic, and threshold specificity. Projector synesthetes, who experience color photisms as spatially colocalized with inducing graphemes, displayed lower phosphene thresholds than associator synesthetes, who experience photisms as internal images, with both exhibiting lower thresholds than controls. These results suggest that phosphene perception is driven by interindividual variation in glutamatergic activity in primary visual cortex and relates to cortical processes underlying individual differences in visuospatial awareness.

GABA predicts time perception.

Our perception of time constrains our experience of the world and exerts a pivotal influence over a myriad array of cognitive and motor functions. There is emerging evidence that the perceived duration of subsecond intervals is driven by sensory-specific neural activity in human and nonhuman animals, but the mechanisms underlying individual differences in time perception remain elusive. We tested the hypothesis that elevated visual cortex GABA impairs the coding of particular visual stimuli, resulting in a dampening of visual processing and concomitant positive time-order error (relative underestimation) in the perceived duration of subsecond visual intervals. Participants completed psychophysical tasks measuring visual interval discrimination and temporal reproduction and we measured in vivo resting state GABA in visual cortex using magnetic resonance spectroscopy. Time-order error selectively correlated with GABA concentrations in visual cortex, with elevated GABA associated with a rightward horizontal shift in psychometric functions, reflecting a positive time-order error (relative underestimation). These results demonstrate anatomical, neurochemical, and task specificity and suggest that visual cortex GABA contributes to individual differences in time perception.

Correction: Gender imbalances in the editorial activities of a selective journal run by academic editors.

[This corrects the article DOI: 10.1371/journal.pone.0294805.].

Virtual reality in functional neurological disorder: a theoretical framework and research agenda for use in the real world.

Functional neurological disorder (FND) is a common and disabling condition at the intersection of neurology and psychiatry. Despite remarkable progress over recent decades, the mechanisms of FND are still poorly understood and there are limited diagnostic tools and effective treatments. One potentially promising treatment modality for FND is virtual reality (VR), which has been increasingly applied to a broad range of conditions, including neuropsychiatric disorders. FND has unique features, many of which suggest the particular relevance for, and potential efficacy of, VR in both better understanding and managing the disorder. In this review, we describe how VR might be leveraged in the treatment and diagnosis of FND (with a primary focus on motor FND and persistent perceptual-postural dizziness given their prominence in the literature), as well as the elucidation of neurocognitive mechanisms and symptom phenomenology. First, we review what has been published to date on the applications of VR in FND and related neuropsychiatric disorders. We then discuss the hypothesised mechanism(s) underlying FND, focusing on the features that are most relevant to VR applications. Finally, we discuss the potential of VR in (1) advancing mechanistic understanding, focusing specifically on sense of agency, attention and suggestibility, (2) overcoming diagnostic challenges and (3) developing novel treatment modalities. This review aims to develop a theoretical foundation and research agenda for the use of VR in FND that might be applicable or adaptable to other related disorders.

Sub-second and multi-second dopamine dynamics underlie variability in human time perception.

Timing behaviour and the perception of time are fundamental to cognitive and emotional processes in humans. In non-human model organisms, the neuromodulator dopamine has been associated with variations in timing behaviour, but the connection between variations in dopamine levels and the human experience of time has not been directly assessed. Here, we report how dopamine levels in human striatum, measured with sub-second temporal resolution during awake deep brain stimulation surgery, relate to participants' perceptual judgements of time intervals. Fast, phasic, dopaminergic signals were associated with underestimation of temporal intervals, whereas slower, tonic, decreases in dopamine were associated with poorer temporal precision. Our findings suggest a delicate and complex role for the dynamics and tone of dopaminergic signals in the conscious experience of time in humans.

Pedunculopontine-induced cortical decoupling as the neurophysiological locus of dissociation.

Mounting evidence suggests an association between aberrant sleep phenomena and dissociative experiences. However, no wake-sleep boundary theory provides a compelling explanation of dissociation or specifies its physiological substrates. We present a theoretical account of dissociation that integrates theories and empirical results from multiple lines of research concerning the domain of dissociation and the regulation of rapid eye movement (REM) sleep. This theory posits that individual differences in the circuitry governing the REM sleep promoting Pedunculopontine Nucleus and Laterodorsal Tegmental Nucleus determine the degree of similarity in the cortical connectivity profiles of wakefulness and REM sleep. We propose that a latent trait characterized by elevated dissociative experiences emerges from the decoupling of frontal executive regions due to a REM sleep-like aminergic/cholinergic balance. The Pedunculopontine-Induced Cortical Decoupling Account of Dissociation (PICDAD) suggests multiple fruitful lines of inquiry and provides novel insights. (PsycInfo Database Record (c) 2023 APA, all rights reserved).