Is alexithymia characterised by impaired interoception? Further evidence, the importance of control variables, and the problems with the Heartbeat Counting Task

Potential mechanisms underlying the association between feeding and eating disorders and autism

There is a reliable association between autism and Feeding and Eating Disorders. Concerningly, where these two conditions co-occur, clinical outcomes of Feeding and Eating Disorders are significantly worse, and treatment less effective, than when the Feeding and Eating Disorders occur in neurotypical individuals. Problematically, the reason for the association between autism and Feeding and Eating Disorders is poorly understood, which constrains advances in clinical care. This paper outlines several possible mechanisms that may underlie the observed association and suggests ways in which they may be empirically tested. Mechanisms are split into those producing an artefactual association, and those reflecting a genuine link between conditions. Artefactual associations may be due to conceptual overlap in both diagnostic criteria and measurement, Feeding and Eating Disorders causing transient autistic traits, or the association being non-specific in nature. A genuine association between autism and Feeding and Eating Disorders may be due to common causal factors, autism directly or indirectly causing Feeding and Eating Disorders, and Feeding and Eating Disorders being a female manifestation of autism.

A roadmap to understanding interoceptive awareness and post-traumatic stress disorder: a scoping review

The concept of interoception has existed since the beginning of the 1900s. It is suggested that humans can observe feelings arising from the body that allows them to develop a sense of their emotional status and physical condition. The term interoceptive awareness appears to originate with clinicians working with individuals who had experienced trauma, in particular Post Traumatic Stress Disorder (PTSD). The purpose of this scoping review was to provide an overview of the existing literature surrounding the combination of these two themes: interoceptive awareness and PTSD. A total of 226 articles were initially screened and 52 articles were retained for comprehensive review. Nine articles were excluded, resulting in 43 studies included in the review. The review aimed to answer: (a) how is interoceptive awareness defined? (b) how is interoceptive awareness measured? (c) what is the function of interoceptive awareness? (d) is there/what is the relationship between interoceptive awareness and PTSD? The scoping review identified nine terms that are used synonymously throughout the literature surrounding interoceptive awareness and PTSD, and three primary ways in which interoceptive awareness is measured in relation to PTSD. The primary function documented was the role interoceptive awareness played in an individual's ability to regulate their emotions, and the most common and compelling function emerging was the association with emotion regulation. The evidence supports the utilisation of a definition of interoceptive awareness to include one that includes the quality of cognitive appraisal and focuses on the adaptive mindful approach to internal physical sensations as opposed to the heightened ruminative self-focus. Limitations and future research are suggested.

Probing corporeal awareness in women through virtual reality induction of embreathment illusion

We capitalized on the respiratory bodily illusion that we discovered in a previous study and called 'Embreathment' where we showed that breathing modulates corporeal awareness in men. Despite the relevance of the issue, no such studies are available in women. To bridge this gap, we tested whether the synchronization of avatar-participant respiration patterns influenced females' bodily awareness. We collected cardiac and respiratory interoceptive measures, administered body (dis)satisfaction questionnaires, and tracked participants' menstrual cycles via a mobile app. Our approach allowed us to characterize the 'Embreathment' illusion in women, and explore the relationships between menstrual cycle, interoception and body image. We found that breathing was as crucial as visual appearance in eliciting feelings of ownership and held greater significance than any other cue with respect to body agency in both women and men. Moreover, a positive correlation between menstrual cycle days and body image concerns, and a negative correlation between interoceptive sensibility and body dissatisfaction were found, confirming that women's body dissatisfaction arises during the last days of menstrual cycle and is associated with interoception. These findings have potential implications for corporeal awareness alterations in clinical conditions like eating disorders and schizophrenia.

Case report: Short-term psychotherapy for alexithymia in a patient with generalized anxiety disorder

Alexithymia is common among patients with generalized anxiety disorder (GAD) and may negatively affect the efficacy of treatment. This case report described a sole short-term psychotherapy focusing on alexithymia for a GAD patient. The intervention extends over 3 weekly 50-minute sessions and incorporates components of: (a) understanding the basic categories of emotions and the importance of processing them consciously and building one's own vocabulary of emotions; (b) developing skills in identifying and labeling emotions and learning to register both positive and negative emotions in daily life; (c) observing and interpreting emotion-related body sensations and learning to get in touch with, be empathetic to, and take care of one's own inner feelings in daily life. The Hamilton Rating Scale for Depression (HRSD), Hamilton Anxiety Rating Scale (HAMA), and Toronto Alexithymia Scale (TAS) were used to evaluate depression, anxiety, and alexithymia before and after the sessions. The results suggested that the treatment was not only effective in reducing alexithymia helping the patient to clarify, identify and describe her feelings, but also effective in reducing anxiety and depression.

Heart activity perception: narrative review on the measures of the cardiac perceptual ability

Measures of cardiac perceptual ability (also called cardiac accuracy) are methods of cardiac interoception, the perception of bodily sensation related to heart activity. This narrative review aims to provide an overview of these methods. We differentiate between three main measurement types: (1) change detection, i.e., when the task is to notice the change in the heart rate; also called: heart rate perception tasks, (2) discrimination tasks, i.e., when the task is to compare the internal sensations with external signal(s); also called: heartbeat detection tasks and (3) tracking tasks, i.e., when the task is to follow and report heartbeats via tapping or counting. We describe some of the new methods under "mixed methods," as they share features with more than one of the large measurement types described above. Specific measures differ in various aspects, such as their focus (heart rhythm vs. single beats), their sensitivity to non-conscious sensations and the calculated indices (e.g., whether significance level by hypothesis test is provided). When a measure of cardiac perceptual ability is chosen, it is advisable to take its characteristics into consideration in light of the planned research.

Irritable bowel syndrome (IBS): could we decide what is behind?

Functional visceral problems are frequently present nowadays in the medical practice probably due to the significant mental and emotional load on people. Although physicians and psychophysiologists are active on the field, still we are far from a complete knowledge, despite the fact that scientists like the Hungarian Professor György Ádám already had initiated a new approach called visceral psychophysiology already a long time ago. In this article, we commemorate Professor Ádám by analyzing one of the most frequent functional disorders, irritable bowel syndrome (IBS), calling psychophysiology for help. First, we try to give a definition, then show the general descriptions and characteristics of IBS. Factors like stress, gender, and gastrointestinal pain are followed by the potential role of the immune system and the neuronal factors as well as the supposed brain mechanisms. We hope that this overview of the IBS-history would show how significant scientists can be decisive in certain fields of the science and practice.

Recognition of others' interoceptive states in those with and without eating disorders

BACKGROUND

The ability to recognize one's own emotions is associated with one's ability to recognize others' emotions. Beyond the domain of emotion, however, the relationship between recognition of one's own internal states (interoception) and others' interoceptive states has not been investigated, either in the typical population or clinical groups with interoceptive difficulties (e.g. eating disorders; EDs).

METHOD

This study investigated recognition of one's own and others' internal states in adults with and without eating disorders, using a high frequency visual noise paradigm. Participants completed self-report measures of interoception, alexithymia (difficulties recognising one's own emotional internal states) and ED symptomatology, and the Heartbeat Counting Task measure of cardiac interoceptive accuracy.

RESULTS

Alexithymia was significantly negatively correlated with recognition of others' interoceptive states. EDs were not associated with difficulties recognising others' interoceptive states.

CONCLUSIONS

The ability to recognise one's own emotional internal states is associated with the recognition of others' interoceptive states, which may contribute to social skills and the ability to care for others.

Basolateral Amygdala Functional Connectivity in Alexithymia: Linking Interoceptive Sensibility and Cognitive Empathy

Emotions rely on bodily states, and perceiving the emotions of others depends on awareness of one's own emotional state. However, the intercorrelations among interoception, alexithymia, and empathy are not well understood, and the neural mechanisms behind this connection are also largely unknown. To address these issues, 297 college students participated in this study, completing measures of interoceptive sensibility (IS), empathy and alexithymia and undergoing resting-state fMRI scans. The functional connectivity of the amygdala was analysed to identify the neural substrates of alexithymia, and mediation analyses were conducted to examine the mediation effect of alexithymia and alexithymia-specific amygdala functional connectivity on the relationship between IS and empathy. The results showed that higher levels of IS were associated with increased cognitive empathy through weakened alexithymia. Functional connectivity analysis indicated that right basolateral amygdala (BLA)-left precuneus connectivity was negatively related to alexithymia, while right BLA-left precentral gyrus connectivity was positively related to alexithymia. Furthermore, right BLA-left precuneus connectivity was found to mediate the impact of interoception on cognitive empathy. In conclusion, this study provides valuable insights into the relationships among IS, alexithymia, and empathy. The right BLA-left precuneus connectivity may serve as a shared neural substrate between interoception and cognitive empathy.

Interoception: Where do we go from here?

In recent years, there has been a significant rise in interest in interoception, the processing of internal bodily signals. This interest has been coupled by increased concerns regarding the measurement and conceptualisation of interoception. Focusing on cardiac interoceptive accuracy, I outline what I believe to be the most pressing issues in the field of interoception-specifically the continued reliance on the heartbeat counting task. I then provide an overview of what I believe to be more general limitations concerning how we measure and conceptualise individual differences in interoception and suggestions for a way forward. Specifically, I believe that by moving beyond single measurements, establishing optimal levels of interoceptive accuracy, and refocusing from accuracy to propensity, we may be able to uncover the real-life relevance of interoceptive abilities.

Challenges and opportunities for conceptualizing intuitive eating in autistic people

Although intuitive eating (IE) has become an increasingly adopted intervention target, current conceptualisations of IE have yet to pivot away from (neuro)normative physiology and phenomenology. Autistic individuals commonly report disordered eating behaviours and/or poorer well-being but appear to benefit from adaptive interventions using an affirmative approach. This article uses autism as a case example to summarise challenges related to IE's prevailing conceptualisation, before proposing how future research and current practice can be extended to the autistic population. Scholars are encouraged to evaluate the full 10-principal IE framework while utilising a participatory-led approach. We argue that research using a mixed methods design is urgently needed to comprehensively explore the (re)conceptualisation of IE in autistic people. While IE shows promise for producing positive outcomes in the autistic population, we discuss the potential challenges for research and practice due to its current emphasis on accurate interoception, emotional awareness and processing, and executive functioning. This suggests the need for research and practice to integrate autistic needs and experiences into future developments with an affirmative approach. Public Significance: IE is an effective intervention for reducing disordered eating behaviours. Autistic individuals commonly present disordered eating behaviours and have unique nutritional needs which often require intervention. However, there is limited understanding of IE among the autistic population. Research-informed definitions involving autistic perspectives will support translating the IE framework to this underrepresented population.

Pain and related suffering reduce attention toward others

BACKGROUND

It has been proposed that the expression of pain-related suffering may lead to an enhanced focus on oneself and reduced attention toward the external world. This study aimed at investigating whether experimentally induced painrelated suffering may lead persons to withdraw into themselves, causing a reduced focus on external stimuli as reflected by impaired performance in a facial recognition task and heightened perception of internal stimuli measured by interoceptive awareness.

METHODS

Thirty-two participants had to recognize different emotional facial expressions (neutral, sad, angry, happy), or neutral geometrical figures under conditions of no pain, low, and high prolonged pain intensities. Interoceptive accuracy was measured using a heartbeat-detection task prior to and following the pain protocol.

RESULTS

Males but not females were slower to recognize facial expressions under the condition of high painful stimulation compared to the condition of no pain. In both, male and female participants, the difficulty in recognizing another person's emotions from a facial expression was directly related to the level of suffering and unpleasantness experienced during pain. Interoceptive accuracy was higher after the pain experiment. However, neither the initial interoceptive accuracy nor the change were significantly related to the pain ratings.

CONCLUSIONS

Our results suggest that long-lasting and intense painful stimuli, which induce suffering, lead to attentional shifts leading to withdrawal from others. These findings contribute to a better understanding of the social dynamics of pain and pain-related suffering.

Increasing familiarity with the heartbeat counting task does not affect performance

BACKGROUND

Interoception is typically defined as the processing and perception of internal signals. A common evaluation of interoceptive abilities is the heartbeat counting task, during which participants count their heartbeats over a period of time. It has been argued recently, however, that performance in this task may reflect processes other than cardiac sensation.

OBJECTIVE

This study aimed to: 1) observe heartbeat counting task performance changes across multiple repetitions of the task; and 2) compare performance in the heartbeat counting task with that for a visual counting task to investigate generalised propensities for how uncertain stimuli are reported.

METHODS

Seventy-nine healthy participants performed seven blocks each of the heartbeat and visual counting tasks. Scores for each of the tasks were compared across blocks to identify any change in performance. Performance in the two tasks was then correlated. The study was preregistered at https://doi.org/10.17605/OSF.IO/GWAB7.

RESULTS

Heartbeat counting task performance did not change over blocks. In contrast, scores for the visual counting task reduced over time. A positive correlation was seen between performance in the two tasks (ρ(79) = .27).

CONCLUSION

Heartbeat counting task performance is stable across repetitions of the task, not changing with increasing familiarity. This suggests that non-interoceptive factors, such as beliefs, may be involved. The correlation between the heartbeat and visual counting tasks may point to a general propensity in counting uncertain stimuli across sensory domains. Together, these results raise questions about the interpretation of the heartbeat counting task as a measure of interoception.

Perception of facial expressions involves emotion specific somatosensory cortex activations which are shaped by alexithymia

Somatosensory cortex (SCx) has been shown to crucially contribute to early perceptual processes when judging other's emotional facial expressions. Here, we investigated the specificity of SCx activity to angry, happy, sad and neutral emotions and the role of personality factors. We assessed participants' alexithymia (TAS-20) and depression (BDI) levels, their cardioceptive abilities and recorded changes in neural activity in a facial emotion judgment task. During the task, we presented tactile probes to reveal neural activity in SCx which was then isolated from visual carry-over responses. We further obtain SCx emotion effects by subtracting SCx activity elicited by neutral emotion expressions from angry, happy, and sad expressions. We find preliminary evidence for distinct modulations of SCx activity to angry and happy expressions. Moreover, the SCx anger response was predicted by individual differences in trait alexithymia. Thus, emotion expressions of others may be distinctly presented in the observer's neural body representation and may be shaped by their personality trait.

Interoception, alexithymia, and anxiety among individuals with alcohol use disorder

Background

Interoception (i.e., the ability to recognize bodily signals), alexithymia (i.e., the inability to recognize emotional states) and negative affect (i.e., unpleasant feelings such as anxiety) have been associated with alcohol use disorder (AUD). Previous research suggests that interoception may underlie alexithymia, which in turn may be associated with negative affectivity. However, this remains to be empirically tested. This study investigates whether alexithymia mediates the association between interoception and anxiety and whether this association differs across individuals with AUD and a healthy control (HC) comparison group.

Methods

The AUD group consisted of 99 participants enrolled in an 8-week abstinence-based inpatient treatment program. The HC group included 103 healthy individuals. The heartbeat counting task (HCT) was used to assess interoception (cardiac interoceptive accuracy). The Toronto Alexithymia Scale (TAS-20) was used to assess alexithymia. The Brief Symptom Inventory (BSI) was used to assess anxiety.

Results

The moderated mediation model with interoception as the predictor, alexithymia as the mediator, and negative affect (i.e., state anxiety) as the dependent variable was tested. The analysis showed that the conditional indirect effect of interoception on anxiety via alexithymia was significant for individuals with AUD [ab = -0.300, bootstrap 95% CI = (-0.618, -0.088)], as well as for HCs [ab = -0.088, bootstrap 95% CI = (-0.195, -0.014)]; however, the conditional indirect effect significantly differed across HCs and individuals with AUD. Namely, the mediated effect was greater among individuals with AUD compared to the HC group.

Conclusion

The results suggests that interoceptive impairment contributes to greater negative affect (i.e., state anxiety) via alexithymia especially for individuals with AUD. Improving emotion recognition via therapeutic methods focused on strengthening interoceptive abilities could improve outcomes for individuals receiving treatment for AUD.

Interoception in functional motor symptoms and functional seizures: Preliminary evidence of intact accuracy alongside reduced insight and altered sensibility

Altered interoception may be a pathophysiological mechanism in functional neurological disorder (FND). However, findings have been inconsistent across interoceptive dimensions in FND including functional motor symptoms (FMS) and seizures (FS). Here, individuals with FMS/FS (n = 17) and healthy controls (HC, n = 17) completed measures of interoceptive accuracy and insight (adapted heartbeat tracking task [HTT] with confidence ratings), a time estimation control task (TET) and the Multidimensional Assessment of Interoceptive Awareness-2 (MAIA-2) to assess interoceptive sensibility. The groups did not differ in interoceptive accuracy (p = 1.00, g = 0.00) or confidence (p = .99, g = 0.004), although the FMS/FS group displayed lower scores on the "Not-Distracting" (p < .001, g = 1.42) and "Trusting" (p = .005, g = 1.17) MAIA-2 subscales, relative to HCs. The groups did not differ in TET performance (p = .82, g = 0.08). There was a positive relationship between HTT accuracy and confidence (insight) in HCs (r = .61, p = .016) but not in FMS/FS (r = 0.11, p = .69). HTT confidence was positively correlated with MAIA-2 "Self-Regulation" (r = 0.77, p = .002) and negatively correlated with FND symptom severity (r = -0.84, p < .001) and impact (r = -0.86, p < .001) in FMS/FS. Impaired interoceptive accuracy may not be a core feature in FMS/FS, but reduced insight and altered sensibility may be relevant. Reduced certainty in self-evaluations of bodily experiences may contribute to the pathogenesis of FND symptoms.

The impact of interoceptive accuracy and stimulation type on the out-of-body experience

People tend to perceive a virtual body standing in front of them as their own if it is either stroked or moving synchronously with their own real body-the out-of-body experience (OBE). We combined synchrony manipulation with two other factors of theoretical interest: the kind of stimulation, visuotactile stimuli or visuomotor correlations, being synchronised and the interoceptive accuracy (IA) of participants, assessed by means of the heartbeat counting task. Results showed that explicit measures of embodiment were systematically affected by synchrony, and this synchrony effect was more pronounced for visuomotor than for visuotactile conditions. The walking drift was affected by IA: In visuotactile conditions, the synchrony effect was pronounced in individuals with low IA, presumably reflecting a stronger impact of the visual information. In visuomotor conditions, however, the synchrony effect was stronger in individuals with high IA, presumably reflecting a stronger impact of re-afferent information generated by the participants' own movements.

Feeling difficult to identify: Alexithymia is inversely associated with positive body image in adults from the United Kingdom

BACKGROUND

Research has increasingly examined the ways in which internal bodily experiences influence body image, including the relationship between alexithymia - the reduced ability to identify and describe one's own emotional feelings and bodily sensations - and negative body image. However, relationships between facets of alexithymia and positive body image remain unexplored.

METHODS

To bridge this gap in the literature, we assessed relationships between facets of alexithymia and multiple, core indices of positive body image in an online sample of adults from the United Kingdom. A total of 395 participants (226 women, 169 men) aged 18 to 84 years completed measures of alexithymia, body appreciation, functionality appreciation, body image flexibility, body acceptance by others, and positive rational acceptance.

RESULTS

Once the effects of age had been accounted for, alexithymia was significantly and negatively associated with all five body image constructs in hierarchical multiple regressions. In the final models, the alexithymia facet of Difficulties Identifying Feeling emerged as a significant and negative predictor of all indices of positive body image.

LIMITATIONS

The use of cross-sectional data limits the causal conclusions that can be drawn.

CONCLUSIONS

These findings extend previous work by demonstrating the unique relationship between alexithymia and positive body image, providing important implications for body image research and practice.

Alexithymia and Alcohol Use: Evaluating the Role of Interoceptive Sensibility with the Revised Multidimensional Assessment of Interoceptive Awareness

Alexithymia has been linked to risky or problematic alcohol use, with a common interpretation invoking deficient emotion regulation and use of alcohol to cope with distress. An alternative explanation positing a general deficit of interoception in alexithymia suggested that poor awareness of internal cues of overconsumption may promote excessive drinking. The present study assessed predictions based on these hypotheses in 337 young adult alcohol users recruited online. Participants completed validated questionnaire indices of alcohol use, alexithymia, emotion regulation, interoceptive sensibility, and sensitivity to reward and punishment. Alcohol use was positively correlated with alexithymia and reward sensitivity, and negatively correlated with emotion regulation as expected, but was uncorrelated with interoceptive sensibility. Alexithymia was not significantly correlated with most dimensions of interoceptive sensibility but was highly negatively correlated with emotion regulation. Hierarchical regression controlling for demographic variables indicated that alexithymia, emotion regulation, sex, and sensitivity to reward and punishment were significant predictors of alcohol use levels. Bootstrapped mediation test controlling for all other variables indicated mediation of the association between alexithymia and alcohol use by deficient emotion regulation but not interoceptive sensibility. Results supported the emotion regulation deficit interpretation of the association of alexithymia with alcohol use. Limitations concerning interoception measurement, online samples, self-report measures, cross-sectional designs, and collection of data during the COVID-19 pandemic are discussed. Future research could follow up on these findings by testing interoceptive accuracy in addition to interoceptive sensibility in relation to alexithymia and alcohol use.

Effects of DBT-based interventions on alexithymia: a systematic review

While dialectical behavior therapy (DBT) appears effective for some psychiatric conditions commonly associated with alexithymia, it is unclear whether DBT improves difficulties experienced by alexithymic individuals. This review investigated the current evidence on the effectiveness of DBT-based interventions in improving alexithymia. A qualitative synthesis of studies that investigated the efficacy of DBT on self-reported alexithymia was performed, identifying eligible studies using EBSCO/Essentials, Google Scholar, PubMed, Web of Science, and PsychINFO databases. Eight studies were identified. Overall, the results were inconclusive due to the heterogeneity of the studies but suggest that DBT-based interventions may be associated with self-reported decreases in alexithymia and increases in the ability to identify emotional states. The literature is limited by significant methodological problems, such as the low number of controlled trials, small samples, and high variability between DBT programs, which increases the risk of bias across study outcomes. More research is needed to reach conclusions regarding the effectiveness of DBT in improving alexithymia. Future studies should conduct randomized controlled trial designs (primarily with active treatment control conditions), greater standardization of DBT-based interventions, and a more in-depth examination of the level of participant involvement in long-term DBT-based interventions may help to understand whether DBT improves alexithymia difficulties.

The relationship between brain neural correlates, self-objectification, and interoceptive sensibility

Interoceptive sensibility refers to the tendency to focus on internal bodily states and the capacity to detect them. As the subjective dimension of interoception, interoceptive sensibility plays a key role in individuals' health. Self-objectification, a process by which individuals tend to adopt a third-person's perspective of their physical self, leads to decreased interoceptive sensibility. However, few studies regarding the neural basis of interoceptive sensibility and the underlying mechanism of the relationship between self-objectification and interoceptive sensibility have been conducted. In this study, we assessed the resting-state brain activity (fractional amplitude of low-frequency fluctuation, fALFF) and connectivity (resting-state functional connectivity, RSFC) of 442 college students. Whole-brain correlation analyses revealed that a higher level of interoceptive sensibility was linked to higher fALFF in the right inferior frontal gyrus (IFG) and left cerebellum and to lower fALFF in the left paracentral lobule and left superior/middle temporal gyrus. Interoceptive sensibility also was negatively associated with the RSFC between the right IFG and the right secondary somatosensory cortex (S2) and the right IFG and the ventral premotor cortex (VPC). These brain regions and connections are mainly responsible for switching attention to internal/external information and processing body-related somatosensory as well as sensory information. Mediation analyses suggested that the fALFF of the right IFG and the RSFC of IFG-S2 and IFG-VPC mediated the relationship between self-objectification and interoceptive sensibility. Overall, these results suggest that the IFG may be the neural marker of interoceptive sensibility and reveal several potential mediation models of the relationship between brain neural correlates and self-objectification and interoceptive sensibility.

Interoceptive attention facilitates emotion regulation strategy use

Background

Method

Results

Conclusions

From Virtual Reality to Regenerative Virtual Therapy: Some Insights from a Systematic Review Exploring Inner Body Perception in Anorexia and Bulimia Nervosa

Despite advances in our understanding of the behavioral and molecular factors that underlie the onset and maintenance of Eating Disorders (EDs), it is still necessary to optimize treatment strategies and establish their efficacy. In this context, over the past 25 years, Virtual Reality (VR) has provided creative treatments for a variety of ED symptoms, including body dissatisfaction, craving, and negative emotions. Recently, different researchers suggested that EDs may reflect a broader impairment in multisensory body integration, and a particular VR technique-VR body swapping-has been used to repair it, but with limited clinical results. In this paper, we use the results of a systematic review employing PRISMA guidelines that explore inner body perception in EDs (21 studies included), with the ultimate goal to analyze the features of multisensory impairment associated with this clinical condition and provide possible solutions. Deficits in interoception, proprioception, and vestibular signals were observed across Anorexia and Bulimia Nervosa, suggesting that: (a) alteration of inner body perception might be a crucial feature of EDs, even if further research is needed and; (b) VR, to be effective with these patients, has to simulate/modify both the external and the internal body. Following this outcome, we introduce a new therapeutic approach-Regenerative Virtual Therapy-that integrates VR with different technologies and clinical strategies to regenerate a faulty bodily experience by stimulating the multisensory brain mechanisms and promoting self-regenerative processes within the brain itself.

Anterior Insula Activation During Cardiac Interoception Relates to Depressive Symptom Severity in HIV-Positive and HIV-Negative Postmenopausal Women

OBJECTIVE

This study aimed to determine whether subclinical symptoms of depression in postmenopausal women are associated with blood oxygen level-dependent (BOLD) activity within the anterior insula during cardiac interoceptive awareness and whether this association differs for persons living with the human immunodeficiency virus (PWH).

METHOD

Twenty-three postmenopausal (mean [standard deviation] age = 56.5 [4.8] years) and 27 HIV-negative women (mean [standard deviation] age = 56.4 [8.0]) underwent functional magnetic resonance imaging while performing a heartbeat detection task. BOLD activation within the bilateral anterior insula based on the contrast of a heartbeat detection condition with and without a distracting tone was entered along with age, HIV status, and psychological stress into two multivariate regression models with self-reported depressive symptom severity as the outcome.

RESULTS

Depressive symptoms did not vary by HIV status, nor was there a main effect or interaction for PWH on insula BOLD activation. Depressive symptoms were positively associated with psychological stress for the left ( β = 0.310, t (49) = 2.352, p = .023) and right brain models ( β = 0.296, t (49) = 2.265, p = .028) as well as the magnitude of BOLD activation in the left insula ( β = 0.290, t (49) = 2.218, p = .032) and right insula ( β = 0.318, t (49) = 2.453, p = .018), respectively. Exploratory analyses revealed that greater magnitude of BOLD activation attributed to exteroceptive noise (tone) was also correlated with self-reported distrust and preoccupation with interoceptive sensations.

CONCLUSIONS

Results support an active interference model for interoceptive awareness wherein greater BOLD signal in the anterior insula in the presence of distracting exteroceptive stimuli may reflect greater prediction error, a feature of depression.

Furthering the language hypothesis of alexithymia: An integrated review and meta-analysis

Alexithymia, including the inability to identify and express one's own feelings, is a subclinical condition responsible for some of the socioemotional symptoms seen across a range of psychiatric conditions. The language hypothesis of alexithymia posits a language-mediated disruption in the development of discrete emotion concepts from ambiguous affective states, exacerbating the risk of developing alexithymia in language-impaired individuals. To provide a critical evaluation, a systematic review and meta-analysis of 29 empirical studies of language functioning in alexithymia was performed. A modest association was found between alexithymia and multi-domain language deficits (r = -0.14), including structural language, pragmatics, and propensity to use emotional language. A more theoretically-relevant subsample analysis comparing alexithymia levels in language-impaired and typical individuals revealed larger effects, but a limited number of studies adopted this approach. A synthesis of 11 emotional granularity studies also found an association between alexithymia and reduced emotional granularity (r = -0.10). Language impairments seem to increase the risk of alexithymia. Heterogeneous samples and methods suggest the need for studies with improved alexithymia assessments.

Shared and unique interoceptive deficits in high alexithymia and neuroticism

Interoception is the perception of internal bodily signals. It is considered fundamental to developing emotional awareness. For this reason, interoceptive deficits are often associated with alexithymia, a condition characterized by difficulty identifying feelings (DIF), difficulty describing feelings (DDF), and an externally-oriented style of thinking (EOT). Yet, the atypical interoception found in alexithymia might be of a similar type and/or more serious than those found in other partially overlapping constructs that entail emotional difficulties and behavioural patterns associated with specific emotional styles. Our study explores this issue by examining the relationship between the interoceptive deficits associated with alexithymia and the Big Five personality traits. A non-clinical sample (N = 504) completed the Toronto Alexithymia Scale, the Big Five Inventory and the Multidimensional Assessment of Interoceptive Awareness. Data were analysed using a network analytic approach that conceives psychological traits as networks of interacting symptoms. The estimated network highlighted that EOT is the alexithymia component least associated with interoception and most associated with lower Openness to Experience. Conversely, DIF and Neuroticism are, respectively, the dimensions of alexithymia and the Big Five most highly associated with interoception. We also compared interoceptive abilities in the four groups of participants whose scores were a) high for both alexithymia and neuroticism, b) high only for alexithymia c), high only for neuroticism, and d) low for both. High alexithymia was especially associated with the tendency to ignore sensations of pain or discomfort, while neuroticism was more indicative of the tendency to worry about these sensations. These results suggest that while high alexithymia and neuroticism share some interoceptive deficits, others are unique to alexithymia and contribute to overall lower interoceptive ability in this condition. Our findings suggest that interventions to enhance awareness of bodily sensations can be beneficial especially for profiles who present high neuroticism and alexithymia.

Brain-heart interactions are modulated across the respiratory cycle via interoceptive attention

Respiration and heartbeat continuously interact within the living organism at many different levels, representing two of the main oscillatory rhythms of the body and providing major sources of interoceptive information to the brain. Despite the modulatory effect of respiration on exteroception and cognition has been recently established in humans, its role in shaping interoceptive perception has been scarcely investigated so far. In two independent studies, we investigated the effect of spontaneous breathing on cardiac interoception by assessing the Heartbeat Evoked Potential (HEP) in healthy humans. In Study 1, we compared HEP activity for heartbeats occurred during inhalation and exhalation in 40 volunteers at rest. We found higher HEP amplitude during exhalation, compared to inhalation, over fronto-centro-parietal areas. This suggests increased brain-heart interactions and improved cortical processing of the heartbeats during exhalation. Further analyses revealed that this effect was moderated by heart rate changes. In Study 2, we tested the respiratory phase-dependent modulation of HEP activity in 20 volunteers during Exteroceptive and Interoceptive conditions of the Heartbeat Detection (HBD) task. In these conditions, participants were requested to tap at each heartbeat, either listened to or felt, respectively. Results showed higher HEP activity and higher detection accuracy at exhalation than inhalation in the Interoceptive condition only. Direct comparisons of Interoceptive and Exteroceptive conditions confirmed stronger respiratory phase-dependent modulation of HEP and accuracy when attention was directed towards the interoceptive stimuli. Moreover, HEP changes during the Interoceptive condition were independent of heart physiology, but were positively correlated with higher detection accuracy at exhalation than inhalation. This suggests a link between optimization of cortical processing of cardiac signals and detection of heartbeats across the respiratory cycle. Overall, we provide data showing that respiration shapes cardiac interoception at the neurophysiological and behavioural levels. Specifically, exhalation may allow attentional shift towards the internal bodily states.

What counts when heartbeats are counted

Schandry's mental heartbeat tracking task is a widely used measure of interoception, assessing heartbeat perception. We classify the factors that contribute to performance on the task as (i) trait-like characteristics, (ii) expectation-related factors, and (iii) factors showing participants' task set. We recommend conducting further research to better understand what exactly the task measures.

Alexithymia, reward sensitivity and excessive exercise in non-binge-eaters versus severe binge eaters: Implications for primary and secondary exercise dependence

A distinction has been made between primary and secondary exercise dependence, with the latter defined as excessive exercise secondary to disordered eating and weight concerns. Based on theoretical considerations from research on the roles of trait factors in addictions, the present study used validated scales to assess alexithymia, sensitivity to reward and punishment, emotion regulation and interoception in relation to exercise dependence symptoms in Australian male and female non-binge eaters (n = 228) and severe binge eaters (n = 126) aged 18-30 yr. In both groups, exercise dependence symptoms were significantly positively associated with reward sensitivity and interoceptive awareness, with the latter two variables predicting exercise dependence symptoms in hierarchical regression models; punishment sensitivity was significantly negatively related to such symptoms. Alexithymia was significantly associated with exercise dependence symptoms only in non-binge eaters; in severe binge eaters, alexithymia explained 0% of unique variance. Male sex was associated with more exercise dependence symptoms in severe binge eaters only. Participants in the severe binge group scored significantly higher on measures of exercise dependence, alexithymia, risky alcohol use, and sensitivity to reward and punishment, and significantly lower on emotion regulation, compared to those in the non-binge group. Hierarchical regression models explained 25% of variance in exercise dependence symptoms in non-binge-eaters and 43% in severe binge eaters. Findings are discussed in terms of the distinction between primary and secondary exercise dependence, the role of alexithymia, study limitations including data collection during the COVID-19 pandemic in Australia, and suggestions for future research.

Alexithymia and binge eating: Maladaptive emotion regulation strategy or deficient interoception?

Alexithymia has been linked to various excessive behaviors as a likely risk factor, including binge eating. Such relationships are often attributed to deficient emotional self-regulation in alexithymia, ostensibly leading to the use of maladaptive, externalized behaviors as strategies for coping with distress. An alternative view is that alexithymia reflects a fundamental deficit of interoceptive awareness that, in the case of binge eating, would suggest that internal satiety cues are poorly recognized, promoting overconsumption. The present study assessed the relationship between alexithymia and binge eating in the context of these competing hypotheses. A large online sample of young adults (n = 532) completed validated measures of alexithymia, emotion regulation, interoception, binge eating, emotional eating motivation, and sensitivity to reward and punishment. Correlations were as expected except for interoception, which showed minimal association with alexithymia or binge eating. In a hierarchical regression controlling for age, gender, education level and student status as covariates, binge eating was predicted by emotional eating motivation, emotion regulation (a negative predictor), alexithymia, and reward sensitivity, with the final model explaining 53% of variance in binge eating. Bootstrapped path analyses controlling for all other variables indicated that the relationship between alexithymia and binge eating was mediated by deficient emotion regulation but not deficient interoception, and that the relationships of both alexithymia and emotion regulation with binge eating were mediated by emotional eating motivation. Results are consistent with the notion that the association of alexithymia with binge eating reflects deficient emotion regulation in alexithymia, which can lead to adoption of maladaptive, externalized behaviors such as binge eating for coping with distress.

Interindividual differences in interoception modulate behavior and brain responses in emotional inference

Emotional experiences are proposed to arise from contextualized perception of bodily responses, also referred to as interoceptive inferences. The recognition of emotions benefits from adequate access to one's own interoceptive information. However, direct empirical evidence of interoceptive inferences and their neural basis is still lacking. In the present fMRI study healthy volunteers performed a probabilistic emotion classification task with videotaped dynamically unfolding facial expressions. In a first step, we aimed to determine functional areas involved in the processing of dynamically unfolding emotional expressions. We then tested whether individuals with higher interoceptive accuracy (IAcc), as assessed by the Heartbeat detection task (HDT), or higher interoceptive sensitivity (IS), as assessed by the Multidimensional Assessment of Interoceptive Awareness, Version 2 (MAIA-2), benefit more from the contextually given likelihood of emotional valence and whether brain regions reflecting individual IAcc and/or IS play a role in this. Individuals with higher IS benefitted more from the biased probability of emotional valence. Brain responses to more predictable emotions elicited a bilateral activity pattern comprising the inferior frontal gyrus and the posterior insula. Importantly, individual IAcc scores positively covaried with brain responses to more surprising and less predictable emotional expressions in the insula and caudate nucleus. We show for the first time that IAcc score is associated with enhanced processing of interoceptive prediction errors, particularly in the anterior insula. A higher IS score seems more likely to be associated with a stronger weighting of attention to interoceptive changes processed by the posterior insula and ventral prefrontal cortex.

Self-Reported Body Awareness: Validation of the Postural Awareness Scale and the Multidimensional Assessment of Interoceptive Awareness (Version 2) in a Non-clinical Adult French-Speaking Sample

Body awareness refers to the individual ability to process signals originating from within the body, which provide a mapping of the body’s internal landscape (interoception) and its relation with space and movement (proprioception). The present study aims to evaluate psychometric properties and validate in French two self-report measures of body awareness: the Postural Awareness Scale (PAS), and the last version of the Multidimensional Assessment of Interoceptive Awareness questionnaire (version 2, MAIA-2). We collected data in a non-clinical, adult sample (N = 308; 61% women, mean age 35 ± 12 years) using online survey, and a subset of the original sample (n = 122; 62% women, mean age 44 ± 11 years) also completed the retest control. Factor analyses and reliability analyses were conducted. Construct validity of the PAS and the MAIA-2 were examined by testing their association with each other, and with self-report measures of personality (Big Five Inventory), alexithymia (Toronto Alexithymia Scale) and dispositional trait mindfulness (Freiburg Mindfulness Inventory). Factor analyses of the PAS supported the same two-factor structure as previously published versions (in other languages). For the MAIA-2, factor analyses suggested that a six-factor structure, excluding Not-Worrying and Not-Distracting factors, could successfully account for a common general factor of self-reported interoception. We found satisfactory internal consistency, construct validity, and reliability over time for both the PAS and the MAIA-2. Altogether, our findings suggest that the French version of the PAS and the MAIA-2 are reliable self-report tools to assess both components of body awareness (proprioception and interoception dimension, respectively).

Interoceptive pathways to understand and treat mental health conditions

An increasing recognition that brain and body are dynamically coupled has enriched our scientific understanding of mental health conditions. Peripheral signals interact centrally to influence how we think and feel, generating our sense of the internal condition of the body, a process known as interoception. Disruptions to this interoceptive system may contribute to clinical conditions, including anxiety, depression, and psychosis. After reviewing the nature of interoceptive disturbances in mental health conditions, this review focuses on interoceptive pathways of existing and putative mental health treatments. Emerging clinical interventions may target novel peripheral treatment mechanisms. Future treatment development requires forward- and back-translation to uncover and target specific interoceptive processes in mental health to elucidate their efficacy relative to interventions targeting other factors.

A heartbeat away from a valid tracking task. An empirical comparison of the mental and the motor tracking task

Individuals' ability to perceive their heartbeats, called cardioceptive accuracy, is assessed with various paradigms. Performance in the mental and a novel motor tracking task that eliminates disturbing tactile sensations was assessed at rest and during walking with the participation of 45 young people. Significantly higher scores in the mental tracking task than in the motor tracking task were found. Scores obtained at rest were consistently higher than their walking counterparts. Motor responses showed no temporal association with heartbeats for 84% of participants at rest and 95% during walking. Overall, participants' cardioceptive accuracy at rest and under slight physical activity was poor. Even if people rely on their heartbeat-related sensations during their daily activity, it is either not the ability that is assessed by the tracking tasks, or it is a relatively poor source of information about the actual state of the body.

The role of interoception in the overlap between eating disorders and autism: Methodological considerations

Significant comorbidity has been demonstrated between feeding and eating disorders and autism. Atypical interoception (perception of bodily signals) may, at least in part, be responsible for this association, as it has been implicated in the aetiology of both conditions. However, significant methodological limitations are impeding progress in this area. This paper provides a brief overview of how interoception has been linked to autism and feeding and eating disorders in both adolescent and adult populations before identifying several issues with current measures of interoception. We suggest that methodological issues may be contributing to the inconsistency in the empirical literature, and provide suggestions for future research.

Atypical interoception is linked to both feeding and eating disorders, and autism and may contribute to the comorbidity between the two.

Existing measures of interoception across cardiac, gastric and respiratory domains are severely limited.

Novel and better‐validated measures of interoception will allow us to better understand the clinical potential of interoceptive training.

The process of emotion identification: Considerations for psychiatric disorders

Emotional regulation is important for mental health and behavioral regulation. A relevant precursor to emotional regulation may involve identification of one's emotions. Here, we propose a model of seven components that may provide a foundation for emotion identification. These factors include baseline mood, monitoring, physiological responses, interoception, past personal experiences regarding emotions/metacognition, context, and labeling. We additionally examine how deficits in different components may contribute to the concept of alexithymia, which is defined by difficulty identifying and describing one's own emotions. Ultimately, we explore how the model may support a relationship between specific psychiatric disorders and alexithymia. The proposed model may help explain emotional identification impairment in multiple psychiatric disorders and guide future research and treatment development efforts.

Alexithymia and Athletic Performance: Beneficial or Deleterious, Both Sides of the Medal? A Systematic Review

Background: Numerous studies have been published on alexithymia among athletes in the last decades. The objective, here, is to provide a critical review on alexithymia in sport and identify elements demonstrating that alexithymic athletes can attain a competitive advantage. Methods: The Center for Reviews and Dissemination guidelines were used. The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines served as the template for reporting the present systematic review. We searched PubMed, Embase, Science Direct, and PsycINFO, without language or date restrictions. Results: Within 72 eligible studies, 23 articles fulfilling the selection criteria were included in the review. Alexithymia is associated with various pathologies and considered to be counter-performing. However, despite considerable suspicion of an advantageous performance effect of alexithymia, there is a lack of data to quantify this effect. Studies identified are heterogeneous (different scales of measurement of alexithymia used or outcomes, different sports), that do not allow us to conclude on an observed causal relationship, because the studies are mostly observational. Conclusion: This systematic review opens a new search field on alexithymia, as possibly promoting performance.

A network analysis of interoception, self-awareness, empathy, alexithymia, and autistic traits

Altered interoception has been consistently found in people with autism spectrum disorder (ASD), and this impairment may contribute to social cognitive dysfunctions. However, little is known regarding the intercorrelations between interoceptive sensibility, autistic, alexithymic, empathic, and self-related traits. We recruited 1360 non-clinical college students and adults to investigate the complex inter-relationship between these variables using network analysis. The resultant network revealed patterns connecting autistic traits to interoceptive sensibility, empathy, alexithymia, and self-awareness, with reasonable stability and test-retest consistency. The node of alexithymia exhibited the highest centrality and expected influence. As revealed by the network comparison test, networks constructed in high- and low-autistic subgroups were comparable in global strength and structure. Our findings suggested that alexithymia serves as an important node, bridging interoceptive deficits, self-awareness, and empathic impairments of autism spectrum disorder. The co-morbidity of alexithymia should be considered carefully in future studies of interoceptive impairments and social deficits in ASD.

Clarifying the relationship between alexithymia and subjective interoception

The long-standing hypothesis that emotions rely on bodily states is back in the spotlight. This has led some researchers to suggest that alexithymia, a personality construct characterized by altered emotional awareness, reflects a general deficit in interoception. However, tests of this hypothesis have relied on heterogeneous assessment methods, leading to inconsistent results. To shed some light on this issue, we administered a battery of self-report questionnaires of interoception and alexithymia to three samples from Italy, the U.S., and Singapore (N = 814). Correlation and machine learning analyses showed that alexithymia was associated with deficits in both subjective interoceptive accuracy and attention. Alexithymics' interoceptive deficits were primarily related to difficulty identifying and describing feelings. Interoception showed a weaker association with externally-oriented thinking as operationalized by the Toronto Alexithymia Scale (TAS-20) and no association with the affective dimension of alexithymia later introduced by the Bermond-Vorst Alexithymia Questionnaire (BVAQ). We discuss our results with reference to the theoretical and psychometric differences between these two measures of alexithymia and their shortcomings. Overall, our results support the view that interoceptive deficits are a core component of alexithymia, although the latter cannot be reduced to the former.

Sex differences in interoceptive accuracy: A meta-analysis

Interoceptive accuracy, the ability to correctly perceive internal signals arising from the body, is thought to be disrupted in numerous mental and physical health conditions. Whilst evidence suggests poorer interoceptive accuracy in females compared to males, raising the possibility that interoceptive differences may relate to sex differences in mental and physical health, results concerning sex differences in interoceptive accuracy are mixed. Given such ambiguity, this meta-analysis aimed to establish the presence or absence of sex differences in interoceptive accuracy across cardiac, respiratory, and gastric domains. A review of 7956 abstracts resulted in 93 eligible studies. Results demonstrated superior accuracy in males across cardiac, but not gastric, tasks, while findings on respiratory tasks were mixed. Effect sizes were consistent across cardiac tasks, but instability and/or moderate heterogeneity was observed across other domains, likely due to the small number of eligible studies. Despite such limitations, results indicate the possibility of sex differences across interoception tasks and domains. Methodological limitations concerning the influence of physiological factors, and directions for future research are discussed.

Do interoception and attending to the upper limbs affect body ownership and body representation in the grasp illusion?

Passively grasping an unseen artificial finger induces ownership over this finger and an illusory coming together of one's index fingers: a grasp illusion. Here we determine how interoceptive ability and attending to the upper limbs influence this illusion. Participants passively grasped an unseen artificial finger with their left index finger and thumb for 3 min while their right index finger, located 12 cm below, was lightly clamped. Experiment 1 (n = 30) investigated whether the strength of the grasp illusion (perceived index finger spacing and perceived ownership) is related to a person's level of interoceptive accuracy (modified heartbeat counting task) and sensibility (Noticing subscale of the Multidimensional Assessment of Interoceptive Awareness). Experiment 2 (n = 30) investigated the effect of providing verbal or tactile cues to guide participants' attention to their upper limbs. On their own, neither interoceptive accuracy and sensibility or verbal and tactile cueing had an effect on the grasp illusion. However, verbal cueing increased the strength of the grasp illusion in individuals with lower interoceptive ability. Across the observed range of interoceptive accuracy and sensibility, verbal cueing decreased perceived index spacing by 5.6 cm [1.91 to 9.38] (mean [95%CI]), and perceived ownership by ∼3 points on a 7-point Likert scale (slope -0.93 [-1.72 to -0.15]). Thus, attending to the upper limbs via verbal cues increases the strength of the grasp illusion in a way that is inversely proportional to a person's level of interoceptive accuracy and sensibility.

Atypical interoception as a common risk factor for psychopathology: A review

The inadequacy of a categorial approach to mental health diagnosis is now well-recognised, with many authors, diagnostic manuals and funding bodies advocating a dimensional, trans-diagnostic approach to mental health research. Variance in interoception, the ability to perceive one's internal bodily state, is reported across diagnostic boundaries, and is associated with atypical functioning across symptom categories. Drawing on behavioural and neuroscientific evidence, we outline current research on the contribution of interoception to numerous cognitive and affective abilities (in both typical and clinical populations), and describe the interoceptive atypicalities seen in a range of psychiatric conditions. We discuss the role that interoception may play in the development and maintenance of psychopathology, as well as the ways in which interoception may differ across clinical presentations. A number of important areas for further research on the role of interoception in psychopathology are highlighted.

Mindfulness and Behavior Change

Initiating and maintaining behavior change is key to the prevention and treatment of most preventable chronic medical and psychiatric illnesses. The cultivation of mindfulness, involving acceptance and nonjudgment of present-moment experience, often results in transformative health behavior change. Neural systems involved in motivation and learning have an important role to play. A theoretical model of mindfulness that integrates these mechanisms with the cognitive, emotional, and self-related processes commonly described, while applying an integrated model to health behavior change, is needed. This integrative review (1) defines mindfulness and describes the mindfulness-based intervention movement, (2) synthesizes the neuroscience of mindfulness and integrates motivation and learning mechanisms within a mindful self-regulation model for understanding the complex effects of mindfulness on behavior change, and (3) synthesizes current clinical research evaluating the effects of mindfulness-based interventions targeting health behaviors relevant to psychiatric care. The review provides insight into the limitations of current research and proposes potential mechanisms to be tested in future research and targeted in clinical practice to enhance the impact of mindfulness on behavior change.

The effect of aerobic exercise on interoception and cognitive function in healthy university students: a non-randomized controlled trial

BACKGROUND

Interoception refers to the body's physiological responses that occur in response to emotions. This phenomenon influences decision-making, an important cognitive ability that affects the maintenance of an exercise routine. However, it is controversial whether interoception is a reliable measure of an individual's traits or their response to emotion. Given this evidence, we hypothesized that performing an exercise with positive feelings could improve interoception and that the rational decision-making capabilities acquired by improved interoception would, in turn, help in maintaining an exercise routine. Persistent aerobic exercise is essential for improving cognitive and musculoskeletal function in the long term. Therefore, we aimed to investigate changes in interoception during moderate-intensity aerobic exercise at a level that might potentially improve cognitive function.

METHODS

We devided 48 healthy university students into an exercise group (n = 37) and a control group (n = 11). The control group did not perform any exercises, while the exercise group performed bench step exercises at an intensity of 50% of heart rate reserve for 30 min a day, three times a week, for three months. We assessed their cognitive function by measuring their auditory information/working memory processing speed using a paced auditory serial addition task (PASAT) and evaluated their interoceptive accuracy (IA) using a heartbeat tracking task at baseline and 1, 2, and 3 months after the start of the exercise intervention.

RESULTS

There was a significant positive correlation between IA and PASAT scores at baseline. However, exercise did not lead to a significant increase in PASAT scores of the exercise group as compared with the control group. IA scores increased at 2 and 3 months after the start of exercise only in the exercise group.

CONCLUSIONS

This preliminary study showed an improvement in interoception after persistent moderate-intensity aerobic exercise. We believe that exercise-induced improvement of interoception may facilitate exercise maintenance through improved cognitive function. Statistical analysis did not explain the non-uniformity of sample sizes, therefore, future studies should have larger sample sizes with equal subjects in each group to allow for better comparability and generalizability.

TRIAL REGISTRATION

UMIN, UMIN000042891. 04/01/2021, retrospectively registered.

On the construct validity of interoceptive accuracy based on heartbeat counting: Cardiovascular determinants of absolute and tilt-induced change scores

Interoceptive accuracy (IAcc) as assessed with the heartbeat counting task (IAcc_HBCT) may be affected by a range of factors including (1.) the ability to adequately detect cardiac signals, indicated by IAcc in a heartbeat discrimination task (IAcc_HBDT), (2.) cardiac signal properties, affected by sympathetic and parasympathetic tone, and (3.) non-interoceptive processes, including time estimation accuracy (TEAcc). In the current study we investigated the contribution of these factors to absolute and Δ IAcc_HBCT scores, induced by passive head-up and head-down tilt in 49 healthy individuals. A set of hierarchical regression models showed IAcc_HBDT scores as the strongest and, across different orthostatic (tilt) conditions, most stable (positive) predictor of absolute and Δ IAcc_HBCT scores. Neither indicators of cardiac signal properties (except for HR in head-down-tilt), nor TEAcc predicted absolute or Δ IAcc_HBCT scores. These findings support the convergent and discriminant validity of absolute and Δ IAcc_HBCT scores.

Measuring interoception: The phase adjustment task

Interoception, perception of one's bodily state, has been associated with mental health and socio-emotional processes. However, several interoception tasks are of questionable validity, meaning associations between interoception and other variables require confirmation with new measures. Here we describe the novel, smartphone-based Phase Adjustment Task (PAT). Tones are presented at the participant's heart rate, but out of phase with heartbeats. Participants adjust the phase relationship between tones and heartbeats until they are synchronous. Data from 124 participants indicates variance in performance across participants which is not affected by physiological or strategic confounds. Associations between interoception and anxiety, depression and stress were not significant. Weak associations between interoception and mental health variables may be a consequence of testing a non-clinical sample. A second study revealed PAT performance to be moderately stable over one week, consistent with state effects on interoception.