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.

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.].

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

The fairness of decisions made at various stages of the publication process is an important topic in meta-research. Here, based on an analysis of data on the gender of authors, editors and reviewers for 23,876 initial submissions and 7,192 full submissions to the journal eLife, we report on five stages of the publication process. We find that the board of reviewing editors (BRE) is men-dominant (69%) and that authors disproportionately suggest male editors when making an initial submission. We do not find evidence for gender bias when Senior Editors consult Reviewing Editors about initial submissions, but women Reviewing Editors are less engaged in discussions about these submissions than expected by their proportion. We find evidence of gender homophily when Senior Editors assign full submissions to Reviewing Editors (i.e., men are more likely to assign full submissions to other men (77% compared to the base assignment rate to men RE of 70%), and likewise for women (41% compared to women RE base assignment rate of 30%))). This tendency was stronger in more gender-balanced scientific disciplines. However, we do not find evidence for gender bias when authors appeal decisions made by editors to reject submissions. Together, our findings confirm that gender disparities exist along the editorial process and suggest that merely increasing the proportion of women might not be sufficient to eliminate this bias. Measures accounting for women's circumstances and needs (e.g., delaying discussions until all RE are engaged) and raising editorial awareness to women's needs may be essential to increasing gender equity and enhancing academic publication.

Time perception reflects individual differences in motor and non-motor symptoms of Parkinson's disease.

Decreasing dopaminergic function is at the core of Parkinson's disease (PD) motor symptoms and changes in dopaminergic action are associated with many comorbid non-motor symptoms in PD. Notably, dopaminergic signaling in the striatum has been shown to play a critical role in the perception of time. We hypothesize that patients with PD perceive time differently and in accordance with their specific comorbid non-motor symptoms and clinical state. This means that individual differences in clinical symptoms may be reflected in individual differences in timing behavior. To test this hypothesis, we recruited patients with PD and compared individual differences in patients' clinical state with their ability to judge intervals of time ranging from 500 ms to 1100 ms while on and off their prescribed dopaminergic medications. We show that medication state (on vs. off medications) did not affect timing behavior, but individual differences in timing behavior are able to predict individual differences in comorbid non-motor symptoms, duration of PD diagnosis, and prescribed dopaminergic medications. We show that comorbid impulse control disorder is associated with temporal overestimation; depression is associated with decreased temporal accuracy; and increased PD duration and prescribed levodopa monotherapy are associated with reduced temporal precision and accuracy. Observed differences in time perception are consistent with hypothesized dopaminergic mechanisms thought to underlie the respective motor and non-motor symptoms in PD. In future work, time perception tasks may augment clinical diagnosis strategies, or help disentangle the neural and cognitive mechanisms underlying PD motor and non-motor symptom etiology.

Reassessing referral of touch following peripheral deafferentation: The role of contextual bias.

Some amputees have been famously reported to perceive facial touch as arising from their phantom hand. These referred sensations have since been replicated across multiple neurological disorders and were classically interpreted as a perceptual correlate of cortical plasticity. Common to all these and related studies is that participants might have been influenced in their self-reports by the experimental design or related contextual biases. Here, we investigated whether referred sensations reports might be confounded by demand characteristics (e.g., compliance, expectation, suggestion). Unilateral upper-limb amputees (N = 18), congenital one-handers (N = 19), and two-handers (N = 22) were repeatedly stimulated with computer-controlled vibrations on 10 body-parts and asked to report the occurrence of any concurrent sensations on their hand(s). To further manipulate expectations, we gave participants the suggestion that some of these vibrations had a higher probability to evoke referred sensations. We also assessed similarity between (phantom) hand and face representation in primary somatosensory cortex (S1), using functional Magnetic Resonance Imaging (fMRI) multivariate representational similarity analysis. We replicated robust reports of referred sensations in amputees towards their phantom hand; however, the frequency and distribution of reported referred sensations were similar across groups. Moreover, referred sensations were evoked by stimulation of multiple body-parts and similarly reported on both the intact and phantom hand in amputees. Face-to-phantom-hand representational similarity was not different in amputees' missing hand region, compared with controls. These findings weaken the interpretation of referred sensations as a perceptual correlate of S1 plasticity and reveal the need to account for contextual biases when evaluating anomalous perceptual phenomena.

Online structured dance/movement therapy reduces bodily detachment in depersonalization-derealization disorder.

BACKGROUND: Depersonalization-derealization disorder (DDD) is a dissociative disorder encompassing pronounced disconnections from the self and from external reality. As DDD is inherently tied to a detachment from the body, dance/movement therapy could provide an innovative treatment approach. MATERIALS AND METHODS: We developed two online dance tasks to reduce detachment either by training body awareness (BA task) or enhancing the salience of bodily signals through dance exercise (DE task). Individuals with DDD (n = 31) and healthy controls (n = 29) performed both tasks individually in a cross-over design. We assessed symptom severity (Cambridge Depersonalization Scale), interoceptive awareness (Multidimensional Assessment of Interoceptive Awareness - II), mindfulness (Five Facet Mindfulness Questionnaire), and body vigilance (Body Vigilance Scale) before, during and after the tasks. RESULTS: At baseline, individuals with DDD exhibited elevated depersonalization-derealization symptoms alongside lower levels of interoceptive awareness and mindfulness compared to controls. Both tasks reduced symptoms in the DDD group, though dance exercise was perceived as easier. The DE task increased mindfulness in those with DDD more than the BA task, whereas controls showed the opposite pattern. In the DDD group, within-subject correlations showed that lower levels of symptoms were associated with task-specific elevations in interoceptive awareness and mindfulness. CONCLUSION: Individual and structured dance/movement practice, performed at home without an instructor present, offers an effective tool to reduce symptoms in DDD and can be tailored to address specific cognitive components of a mindful engagement with the body.

Time perception reflects individual differences in motor and non-motor symptoms of Parkinson's disease.

Dopaminergic signaling in the striatum has been shown to play a critical role in the perception of time. Decreasing striatal dopamine efficacy is at the core of Parkinson's disease (PD) motor symptoms and changes in dopaminergic action have been associated with many comorbid non-motor symptoms in PD. We hypothesize that patients with PD perceive time differently and in accordance with their specific comorbid non-motor symptoms and clinical state. We recruited patients with PD and compared individual differences in patients' clinical features with their ability to judge millisecond to second intervals of time (500ms-1100ms) while on or off their prescribed dopaminergic medications. We show that individual differences in comorbid non-motor symptoms, PD duration, and prescribed dopaminergic pharmacotherapeutics account for individual differences in time perception performance. We report that comorbid impulse control disorder is associated with temporal overestimation; depression is associated with decreased temporal accuracy; and PD disease duration and prescribed levodopa monotherapy are associated with reduced temporal precision and accuracy. Observed differences in time perception are consistent with hypothesized dopaminergic mechanisms thought to underlie the respective motor and non-motor symptoms in PD, but also raise questions about specific dopaminergic mechanisms. In future work, time perception tasks like the one used here, may provide translational or reverse translational utility in investigations aimed at disentangling neural and cognitive systems underlying PD symptom etiology. One Sentence Summary: Quantitative characterization of time perception behavior reflects individual differences in Parkinson's disease motor and non-motor symptom clinical presentation that are consistent with hypothesized neural and cognitive mechanisms.

Current Practices, Experiences, and Views in Clinical Hypnosis: Findings of an International Survey.

An online survey of 691 clinicians who use hypnosis was conducted in 31 countries to gain a broad real-world picture of current practices, views, and experiences in clinical hypnosis. Among 36 common clinical uses, stress reduction, wellbeing and self-esteem-enhancement, surgery preparations, anxiety interventions, mindfulness facilitation, and labor and childbirth applications were the most frequently rated as highly effective (each by ≥70% of raters) in the clinicians' own experience. Adverse hypnosis-associated effects had been encountered by 55% of clinicians but were generally short-lived and very rarely judged as serious. The most common hypnosis approaches used were Ericksonian (71%), hypnotic relaxation therapy (55%), and traditional hypnosis (50%). Almost all respondents reported regularly using other therapeutic modalities alongside hypnosis. Among a range of client variables potentially affecting therapy, most clinicians rated hypnotist-client rapport (88%) and client motivation (75%) as very or extremely important factors for successful hypnotherapy. The majority of respondents had conducted hypnosis treatment via teletherapy, and 54% of those estimated it to be as effective as in-person treatment.

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).

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.

Ayahuasca: A review of historical, pharmacological, and therapeutic aspects.

Ayahuasca is a psychedelic plant brew originating from the Amazon rainforest. It is formed from two basic components, the Banisteriopsis caapi vine and a plant containing the potent psychedelic dimethyltryptamine (DMT), usually Psychotria viridis. Here we review the history of ayahuasca and describe recent work on its pharmacology, phenomenological responses, and clinical applications. There has been a significant increase in interest in ayahuasca since the turn of the millennium. Anecdotal evidence varies significantly, ranging from evangelical accounts to horror stories involving physical and psychological harm. The effects of the brew on personality and mental health outcomes are discussed in this review. Furthermore, phenomenological analyses of the ayahuasca experience are explored. Ayahuasca is a promising psychedelic agent that warrants greater empirical attention regarding its basic neurochemical mechanisms of action and potential therapeutic application.

Absorption and dissociation mediate the relationship between direct verbal suggestibility and impulsivity/compulsivity.

Direct verbal suggestibility refers to the capacity for an individual to experience perceptual, motor, affective and cognitive changes in response to verbal suggestions. Suggestibility is characterized by pronounced, yet reliable, inter-individual differences. Previous research and theoretical considerations suggest that greater impulsivity and compulsivity is associated to higher suggestibility, but the characteristics and mediating factors of this association are poorly understood. Using established psychometric measures in an online sample, we found positive correlations between the domain comprising impulsivity, compulsivity and behavioural activation, and the domain of suggestibility, dissociation and absorption. We also observed that dissociation and absorption mediated the link between suggestibility and impulsivity, and between suggestibility and behavioural activation, respectively. These results confirm the positive link between suggestibility and the impulsivity/compulsivity domain and shed new light on the characterisation of traits associated with suggestibility.

Pupillometry tracks errors in interval timing.

Recent primate studies suggest a potential link between pupil size and subjectively elapsed duration. Here, we sought to investigate the relationship between pupil size and perceived duration in human participants performing two temporal bisection tasks in the subsecond and suprasecond interval ranges. In the subsecond task, pupil diameter was greater during stimulus processing when shorter intervals were overestimated but also during and after stimulus offset when longer intervals were underestimated. By contrast, in the suprasecond task, larger pupil diameter was observed only in the late stimulus offset phase prior to response prompts when longer intervals were underestimated. This pattern of results suggests that pupil diameter relates to an error monitoring mechanism in interval timing. These results are at odds with a direct relationship between pupil size and the perception of duration but suggest that pupillometric variation might play a key role in signifying errors related to temporal judgments. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Assessing responsiveness to direct verbal suggestions in depersonalization-derealization disorder.

The dissociative disorders and germane conditions are reliably characterized by elevated responsiveness to direct verbal suggestions. However, it remains unclear whether atypical responsiveness to suggestion is similarly present in depersonalization-derealization disorder (DDD). 55 DDD patients and 36 healthy controls completed a standardised behavioural measure of direct verbal suggestibility that includes a correction for compliant responding (BSS-C), and psychometric measures of depersonalization-derealization (CDS), mindfulness (FFMQ), imagery vividness (VVIQ), and anxiety (GAD-7). Relative to controls, patients did not exhibit elevated suggestibility (g = 0.26, BF10 = .11) but displayed significantly lower mindfulness (g = 1.38), and imagery vividness (g = 0.63), and significantly greater anxiety (g = 1.39). Although suggestibility did not correlate with severity of depersonalization-derealization symptoms in controls, r = -.03 [95% CI: -.36, .30], there was a weak tendency for a positive association in patients, r = .25, [95% CI: -.03, .48]. Exploratory analyses revealed that patients with more severe anomalous bodily experiences were also more responsive to suggestion, an effect not seen in controls. This study demonstrates that DDD is not characterized by elevated responsiveness to direct verbal suggestions. These results have implications for the aetiology and treatment of this condition, as well as its classification as a dissociative disorder in psychiatric nosology.

The temporal context in bayesian models of interval timing: Recent advances and future directions.

Sensory perception, motor control, and cognition necessitate reliable timing in the range of milliseconds to seconds, which implies the existence of a highly accurate timing system. Yet, partly owing to the fact that temporal processing is modulated by contextual factors, perceived time is not isomorphic to physical time. Temporal estimates exhibit regression to the mean of an interval distribution (global context) and are also affected by preceding trials (local context). Recent Bayesian models of interval timing have provided important insights regarding these observations, but questions remain as to how exposure to past intervals shapes perceived time. In this article, we provide a brief overview of Bayesian models of interval timing and their contribution to current understanding of context effects. We then proceed to highlight recent developments in the field concerning precision weighting of Bayesian evidence in both healthy timing and disease and the neurophysiological and neurochemical signatures of timing prediction errors. We further aim to bring attention to current outstanding questions for Bayesian models of interval timing, such as the likelihood conceptualization. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Hypnotic suggestibility in dissociative and related disorders: A meta-analysis.

Elevated responsiveness to verbal suggestions is hypothesized to represent a predisposing factor for the dissociative disorders (DDs) and related conditions. However, the magnitude of this effect has not been estimated in these populations nor has the potential moderating influence of methodological limitations on effect size variability across studies. This study assessed whether patients with DDs, trauma- and stressor-related disorders (TSDs), and functional neurological disorder (FND) display elevated hypnotic suggestibility. A systematic literature search identified 20 datasets. A random-effects meta-analysis revealed that patients displayed greater hypnotic suggestibility than controls, Hedges's g = 0.92 [0.66, 1.18]. This effect was observed in all subgroups but was most pronounced in the DDs. Although there was some evidence for publication bias, a bias-corrected estimate of the group effect remained significant, g = 0.57 [0.30, 0.85]. Moderation analyses did not yield evidence for a link between effect sizes and methodological limitations. These results demonstrate that DDs and related conditions are characterized by elevated hypnotic suggestibility and have implications for the mechanisms, risk factors, and treatment of dissociative psychopathology.

The contribution of latent factors of executive functioning to mind wandering: an experience sampling study.

Accumulating evidence suggests that individuals with greater executive resources spend less time mind wandering. Independent strands of research further suggest that this association depends on concentration and a guilty-dysphoric daydreaming style. However, it remains unclear whether this association is specific to particular features of executive functioning or certain operationalizations of mind wandering, including task-unrelated thoughts (TUTs, comprising external distractions and mind wandering) and stimulus-independent and task-unrelated thoughts (SITUTs, comprising mind wandering only). This study sought to clarify these associations by using confirmatory factor analysis to compute latent scores for distinct executive functions based on nine cognitive tasks and relating them to experience sampling reports of mind wandering. We expected that individuals with greater executive control (specifically updating) would show a stronger reduction in SITUTs as momentary concentration and guilty-dysphoric style increase. A bifactor model of the cognitive battery indicated a general factor (common executive functioning) and ancillary factors (updating and shifting). A significant interaction between updating and concentration on mind wandering was observed with mind wandering defined as TUTs, but not as SITUTs (N = 187). A post hoc analysis clarified this discrepancy by showing that as concentration increases, both external distractions and mind wandering decrease more strongly among people with greater updating. Moreover, common executive functioning predicted a more negative slope of guilty-dysphoric style on SITUTs, whereas updating and shifting predicted more positive slopes. The opposite slopes of these executive functions on daily life mind wandering may reflect a stability-flexibility trade-off between goal maintenance and goal replacement abilities.

Hypnotherapy for procedural pain, itch, and state anxiety in children with acute burns: a feasibility and acceptability study protocol.

BACKGROUND: Burns and related procedures are painful and distressing for children, exposing them to acute and chronic sequelae that can negatively affect their physiological, psychological, and social functions. Non-pharmacological interventions such as distraction techniques are beneficial adjuncts to pharmacological agents for procedural pain, state anxiety, and itch in children with burns but have limitations (e.g. lack of research on burn-related itch, tailoring, and consensus on optimal treatment). Hypnotherapy is a non-pharmacological intervention that can be tailored for varied settings and populations with evidence of benefit for itch and superior effectiveness in comparison to other non-pharmacological interventions for children's procedural pain and state anxiety. Thus, children with burns can benefit from hypnotherapy as an adjunct to pharmacological agents. Yet, in paediatric burns, rigorous studies of effectiveness are limited and no studies have been identified that screen for hypnotic suggestibility, an important predictor of hypnotherapy outcomes. Considering potential barriers to the delivery of hypnotherapy in paediatric burns, the proposed study will examine the feasibility and acceptability of hypnotic suggestibility screening followed by hypnotherapy for procedural pain, state anxiety, and itch in children with acute burns. METHODS: An observational mixed-methods feasibility and acceptability study will be conducted over 15 weeks. Eligible children (N = 30) aged 4 to 16 years presenting to a paediatric burns outpatient centre in a metropolitan children's hospital in Australia with acute burns requiring dressing changes will be included. Eligible parents of children (N = up to 30) and clinicians who perform dressing changes (N = up to 20) will also be included. Child participants screened as having medium to high suggestibility as assessed by behavioural measures will receive hypnotherapy during dressing changes. A process evaluation will target feasibility and acceptability as primary outcomes and implementation (i.e. fidelity in delivery), reach, potential effectiveness, and adoption of evaluation procedures and intervention as secondary outcomes. DISCUSSION: Ethical approval was obtained from the Queensland Children's Hospital and Health Service ethics committee. Results will be published in peer-reviewed publications and conference proceedings. The findings will guide the design of future trials on the effectiveness of hypnotherapy and inform the development of child-centred hypnotic interventions in children with burns. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12620000988954.