On the Relationship Between Interoceptive Awareness and Alexithymia: Is Interoceptive Awareness Related to Emotional Awareness?

Alexithymia: a general deficit of interoception

Alexithymia is a sub-clinical construct, traditionally characterized by difficulties identifying and describing one's own emotions. Despite the clear need for interoception (interpreting physical signals from the body) when identifying one's own emotions, little research has focused on the selectivity of this impairment. While it was originally assumed that the interoceptive deficit in alexithymia is specific to emotion, recent evidence suggests that alexithymia may also be associated with difficulties perceiving some non-affective interoceptive signals, such as one's heart rate. It is therefore possible that the impairment experienced by those with alexithymia is common to all aspects of interoception, such as interpreting signals of hunger, arousal, proprioception, tiredness and temperature. In order to determine whether alexithymia is associated with selectively impaired affective interoception, or general interoceptive impairment, we investigated the association between alexithymia and self-reported non-affective interoceptive ability, and the extent to which individuals perceive similarity between affective and non-affective states (both measured using questionnaires developed for the purpose of the current study), in both typical individuals (n = 105 (89 female), mean age = 27.5 years) and individuals reporting a diagnosis of a psychiatric condition (n = 103 (83 female), mean age = 31.3 years). Findings indicated that alexithymia was associated with poor non-affective interoception and increased perceived similarity between affective and non-affective states, in both the typical and clinical populations. We therefore suggest that rather than being specifically associated with affective impairment, alexithymia is better characterized by a general failure of interoception.

Uncomfortably numb: new evidence for suppressed emotional reactivity in response to body-threats in those predisposed to sub-clinical dissociative experiences

INTRODUCTION

Depersonalisation and derealisation disorders refer to feelings of detachment and dissociation from one's "self" or surroundings. A reduced sense of self (or "presence") and emotional "numbness" is thought to be mediated by aberrant emotional processing due to biases in self-referent multi-sensory integration. This emotional "numbing" is often accompanied by suppressed autonomic arousal to emotionally salient stimuli.

METHODS

118 participants completed the Cambridge Depersonalisation scale [Sierra, & Berrios, 2000. The Cambridge Depersonalisation Scale: A new instrument for the measurement of depersonalisation. Psychiatry Research, 93, 153-164)] as an index of dissociative anomalous experience. Participants took part in a novel "Implied Body-Threat Illusion" task; a pantomimed injection procedure conducted directly onto their real body (hand). Objective psychophysiological data were recorded via standardised threat-related skin conductance responses and finger temperature measures.

RESULTS

Individuals predisposed to depersonalisation/derealisation revealed suppressed skin conductance responses towards the pantomimed body-threat. Although the task revealed a reliable reduction in finger temperature as a fear response, this reduction was not reliably associated with measures of dissociative experience.

CONCLUSIONS

The present findings significantly extend previous research by revealing emotional suppression via a more direct body-threat task, even for sub-clinical groups. The findings are discussed within probabilistic and predictive coding frameworks of multi-sensory integration underlying a coherent sense of self.

Normal interoceptive accuracy in women with bulimia nervosa

Previous studies suggest that patients suffering from bulimia nervosa (BN) have difficulties in perceiving internal bodily signals, mostly assessed by self-report questionnaires. Whether interoception is, in this case, attenuated or not remains an open question. Therefore, interoceptive processes were examined in twenty-three patients with current BN and were compared to healthy participants. We investigated Interoceptive Accuracy (IAc) assessed by the heartbeat detection task and Interoceptive Awareness (IA) assessed by the Eating Disorder Inventory-2. Patients with BN and healthy participants did not differ in terms of IAc when controlling for BMI, depression and anxiety, whereas IA among BN patients was found to have decreased. Although IAc and IA were not related among controls, we observed an inverse correlation in BN, suggesting that an abnormal overlap between these two levels of interoceptive signal processing is present in BN. The current study introduces a new perspective concerning the role of interoceptive processes in BN and generates further questions regarding the therapeutic utility of methods targeting the interaction between different levels of interoception in the treatment of BN.

Links among emotional awareness, somatic awareness and autonomic homeostatic processing

Emotional awareness and somatic interoceptive awareness are essential processes for human psychosomatic health. A typical trait of lacking emotional awareness related to psychosomatic symptoms is alexithymia. In contrast, alexisomia refers to the trait of lacking somatic awareness. Links between emotional and somatic awareness and homeostatic processing are also significant for the psychosomatic health. The purpose of the present paper is to review the links among emotional awareness, somatic interoceptive awareness and autonomic homeostatic processing. On the basis of the collected evidence, the following arguments were presented¹: (1) The main subcortical neural substrates for these processes are limbic-related systems, which are also responsible for autonomic functions for optimization of homeostatic efficiency. (2) Considerable studies have shown that autonomic activity and/or reactivity to stress correlate with both emotional and interoceptive awareness. A hypothesis was advocated about the links between the two types of awareness and autonomic function: Autonomic dysfunction, especially high sympathetic tone at baseline and/or attenuated reactivity or variability to stress, appears to be involved in disturbance of emotional and interoceptive awareness. (3) Several studies suggest that a link or a cooperative relationship exists between emotional and somatic awareness, and that somatic awareness is the more fundamental of the two types of awareness. Emotional awareness, somatic awareness and autonomic homeostatic processing generally occur in parallel or concurrently. However, some complex features of pathologies include coexistence of reduced interoceptive awareness and somatosensory amplification. The autonomic homeostatic process is fundamentally involved in emotional and somatic awareness. Investigation of these types of awareness with both neuroimaging evaluations and estimation of peripheral autonomic function are required as next steps for exploration of the relationship between awareness and human somatic states including somatic symptoms as well as general psychosomatic health.

Alexithymia, not autism, is associated with impaired interoception

It has been proposed that Autism Spectrum Disorder (ASD) is associated with difficulties perceiving the internal state of one's body (i.e., impaired interoception), causing the socio-emotional deficits which are a diagnostic feature of the condition. However, research indicates that alexithymia - characterized by difficulties in recognizing emotions from internal bodily sensations - is also linked to atypical interoception. Elevated rates of alexithymia in the autistic population have been shown to underpin several socio-emotional impairments thought to be symptomatic of ASD, raising the possibility that interoceptive difficulties in ASD are also due to co-occurring alexithymia. Following this line of inquiry, the present study examined the relative impact of alexithymia and autism on interoceptive accuracy (IA). Across two experiments, it was found that alexithymia, not autism, was associated with atypical interoception. Results indicate that interoceptive impairments should not be considered a feature of ASD, but instead due to co-occurring alexithymia.

Respiratory sinus arrhythmia as a potential measure in substance use treatment--outcome studies

BACKGROUND AND AIMS

Dysfunction of physiological regulation systems may underlie the disrupted emotional and self-regulatory processes among people with substance use disorder (SUD). This paper reviews evidence as to whether or not respiratory sinus arrhythmia (RSA), as a psychophysiological index of emotional regulation, could provide useful information in treatment-outcome research to provide insights into recovery processes.

METHODS

We reviewed the use of RSA in clinical research and studies on SUD treatment. Search terms for the review of RSA in clinical research included respiratory sinus arrhythmia, heart rate variability, vagal, cardiac vagal control, psychophysiology, intervention, treatment, mindfulness, mind-body, mental health, substance use, chemical dependence, regulation and emotion regulation. For the review of RSA in intervention studies, we included only those that provided adequate description of psychophysiological methods, and examined RSA in the context of an intervention study.

RESULTS

RSA appears to be able to provide an index of self-regulatory capacity; however, it has been little used in either intervention or treatment research. Of the four intervention studies included in this review, all were mindfulness-based interventions. Two studies were with substance-using samples, and both showed pre-post increases in RSA and related improved substance use outcomes. Two of the three studies were randomized controlled trials (RCTs), and both showed significant increases in RSA in the experimental compared to comparison condition.

CONCLUSION

Respiratory sinus arrhythmia may be a useful index of emotional regulation in people with substance use disorder, and a potential measure of underlying mechanisms for SUD treatment studies, particularly mindfulness-based interventions.

Neural connectivity of alexithymia: Specific association with major depressive disorder

BACKGROUND

Alexithymia has been frequently associated with major depression disorders (MDD). Yet little is known about the exact relationship of alexithymia and MDD. In order to explore this subject matter, the neural connectivity associated with alexithymia in people with MDD and matched nonclinical controls were compared.

METHODS

Twenty-two females diagnosed with first-episode MDD and twenty-one matched nonclinical controls were MRI brain-scanned with diffusion-tensor-imaging and resting-state-functional-imaging methods, and self-reported the Chinese 20-item Toronto Alexithymia Scale.

RESULTS

Voxel-wise multiple regression analysis showed a group interaction effect regarding the correlation between white-matter-connectivity and alexithymia. Significant correlations were observed at the corpus-callosum in MDDs and at the right superior-longitudinal-fasciculus in the controls. These findings were then used to derive seeds for analyzing resting-state-functional-connectivity in each group separately. The results further revealed that alexithymia in MDDs were associated with reduced functional-connectivity in the right precentral-gyrus and several regions of the brain on the right which are associated with cognitive regulation in the default-mode-network. In contrast, among the control subjects, alexithymia was correlated with increased functional-connectivity between the right inferior-frontal-gyrus-triangularis and the right superior-occipital-lobe, which is associated with emotional response to external stimuli.

LIMITATIONS

Better participant selection, especially recruitment of medication-free samples, and the engagement of additional alexithymia assessments, should be considered in future investigations.

CONCLUSIONS

These findings supported our a priori hypothesis that MDDs and controls have distinct white-matter correlates of alexithymia, and these corresponded to the existing proposed neural correlates for the cognitive and affective characteristics of alexithymia respectively. Extended impacts of these microstructural changes on remote functional networks might help explain the distinct behavioral characteristics of alexithymia for these groups, as well as implications for therapeutic intervention of MDD.

Evaluation of Interoceptive Awareness in Alcohol-Addicted Patients

INTRODUCTION

Interoceptive awareness (IA) is defined as an ability to accurately perceive interoceptive processes, which comprise receiving, processing, and integrating body-relevant signals together with external stimuli. Interoceptive processes affect the motivated approach or avoidance behavior toward stimuli. Alcohol and other substances have effects on the autonomic system that result in altered interoceptive processes. Individuals who have disturbed IA may be at a higher risk of addiction because they are not able to utilize sufficiently body-relevant signals to guide their decision-making. The hypothesis that IA in alcohol-addicted patients would be affected and that the disturbed IA would be associated with alcohol craving was tested in this study.

METHODS

The study was conducted with 55 patients diagnosed with alcohol addiction according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) criteria and who had been sober for at least two weeks and 52 non-addicted healthy controls. IA measurements were performed using the heartbeat perception performance method, which determines participants' awareness of their own heartbeat by comparing the number of subjectively perceived heartbeats with an objective heart rate measure recorded with ECG during four separate intervals. In addition, the Alcohol Use Disorders Identification Test (AUDIT), Penn Alcohol Craving Scale (PACS), and Obsessive Compulsive Drinking Scale (OCDS) were performed on the alcohol-addicted patient group.

RESULTS

IA scores were significantly lower in the alcohol-addicted patients than the control subjects. IA scores of alcohol-addicted patients were negatively correlated with the levels of alcohol craving sensations according to the PACS results.

CONCLUSION

Our results corroborate the suggestion that IA in alcohol-addicted patients would be affected and that poor IA would be associated with alcohol craving and could be a maintaining factor for drinking behavior.

Touching the Lived Body in Patients with Medically Unexplained Symptoms. How an Integration of Hands-on Bodywork and Body Awareness in Psychotherapy may Help People with Alexithymia

Medically unexplained symptoms (MUS) are a considerable presenting problem in general practice. Alexithymia and difficulties with mental elaboration of bodily arousal are hypothesized as a key mechanism in MUS. In turn, this inability influences the embodied being and participating of these patients in the world, which is coined as 'the lived body' and underlies what is mostly referred to as body awareness (BA). The present article explores a more innovative hypothesis how hands-on bodywork can influence BA and serve as a rationale for a body integrated psychotherapeutic approach of MUS. Research not only shows that BA is a bottom-up 'bodily' affair but is anchored in a interoceptive-insular pathway (IIP) which in turn is deeply connected with autonomic and emotional brain areas as well as verbal and non-verbal memory. Moreover, it is emphasized how skin and myofascial tissues should be seen as an interoceptive generator, if approached in the proper manual way. This article offers supportive evidence explaining why a 'haptic' touch activates this IIP, restores the myofascial armored body, helps patients rebalancing their window of tolerance and facilitates BA by contacting their bodily inner-world. From a trans-disciplinary angle this article reflects on how the integration of bodywork with non-directive verbal guidance can be deeply healing and resourcing for the lived body experience in MUS. In particular for alexithymic patients this approach can be of significance regarding their representational failure of bodily arousal.

Acquired alexithymia following damage to the anterior insula

Alexithymia is a subclinical condition characterized by impaired awareness of one's emotional states, which has profound effects on mental health and social interaction. Despite the clinical significance of this condition, the neurocognitive impairment(s) that lead to alexithymia remain unclear. Recent theoretical models suggest that impaired anterior insula (AI) functioning might be involved in alexithymia, but conclusive evidence for this hypothesis is lacking. We measured alexithymia levels in a large sample of brain-injured patients (N=129) and non-brain-injured control participants (N=33), to determine whether alexithymia can be acquired after pronounced damage to the AI. Alexithymia levels were first analysed as a function of group, with patients separated into four groups based on AI damage: patients with >15% damage to AI, patients with <15% damage to AI, patients with no damage to AI, and healthy controls. An ANOVA revealed that alexithymia levels varied across groups (p=0.009), with >15% AI damage causing higher alexithymia relative to all other groups (all p<0.01). Next, a multiple linear regression model was fit with the degree of damage to AI, the degree of damage to a related region (the anterior cingulate cortex, ACC), and the degree of damage to the whole brain as predictor variables, and alexithymia as the dependent variable. Critically, increased AI damage predicted increased alexithymia after controlling for the other two regressors (ACC damage; total lesion volume). Collectively, our results suggest that pronounced AI damage causes increased levels of alexithymia, providing critical evidence that this region supports emotional awareness.

Understanding the role of personality and alexithymia in food preferences and PROP taste perception

Taste perception and food preferences are influenced by a variety of factors, including personality characteristics. The aims of this study were to examine the role of personality characteristics, such as alexithymia (a personality construct characterized by inability to identify, describe, and work with one's own feelings), in: 1) taste responses to the bitter genetic taste-marker PROP and 2) food liking. We studied 649 healthy subjects residing in six genetically-isolated villages of Northeast Italy. Data on PROP taste responsiveness, food liking, personality characteristics and TAS2R28 genotypes were collected. Results showed that PROP non-tasters had higher alexithymia scores than PROP tasters. Moreover, the presence of alexithymia in heterozygous individuals for the rs1726886 polymorphism of the TAS2R38 gene was associated with a reduction in the perceived intensity of PROP. Finally, higher alexithymia scores were associated with liking of alcohol, sweets and fats/meats whereas lower alexithymia scores were related to liking of vegetables, condiments and strong cheeses, Measures of temperament, character, anxiety and depression were also related to food liking. Our findings suggest that: 1) alexithymia, in addition to the TAS2R38 polymorphism, may play a role in responsiveness to the aversive and bitter taste of PROP; and 2) alexithymia, in combination with other personality traits, may provide important insights for better understanding food liking.

Interoceptive awareness in patients with functional neurological symptoms

Historically, emotional factors, such as trauma or psychological conflict, have been suggested as causal factors of functional motor disorders (FMD). More recent approaches have instead stressed potential neural and cognitive abnormalities in the allocation and maintenance of attention. Yet these studies have mostly focused on how attention is allocated to exteroceptive signals about the state of the body. Given the proposed important role of interoception for emotion, the study of FMD patients' ability to monitor their interoceptive signals may serve as a useful, mechanistic link between studies that aim to identify key emotional factors in FMD, and those that examine specific sensorimotor or cognitive abnormalities. In the current study, we compared the interoceptive awareness of a group of individuals with FMD (N=16) with a group of healthy controls (N=17). We employed a commonly used heartbeat detection task which tracks the level of concordance between one's heart rate and its subjective perception, as a proxy for interoceptive awareness more generally. We found that FMD patients have lower interoceptive accuracy than healthy subjects, and such reduced interoceptive accuracy was predictive of their depressive symptoms, as well as their tendency to focus on the external features of their body (self-objectification). Contary to our predictions, interoceptive accuracy was not predictive of alexithymia. These results suggest a potental trade-off between the allocation of attention to internal versus external aspects of the body in FMD. More generally, they warrant further investigation of interoceptive awareness in this population, as a means to understand their emotional abnormalities at a more mechanistic level than studies concentrating on traumatic life events and related risk factors.

The Relevance of Interoception in Chronic Tinnitus: Analyzing Interoceptive Sensibility and Accuracy

In order to better understand tinnitus and distress associated with tinnitus, psychological variables such as emotional and cognitive processing are a central element in theoretical models of this debilitating condition. Interoception, that is, the perception of internal processes, may be such a psychological factor relevant to tinnitus. Against this background, 20 participants suffering from chronic tinnitus and 20 matched healthy controls were tested with questionnaires, assessing interoceptive sensibility, and participated in two tasks, assessing interoceptive accuracy: the Schandry task, a heartbeat estimation assignment, and a skin conductance fluctuations perception task assessing the participants' ability to perceive phasic increases in sympathetic activation were used. To test stress reactivity, a construct tightly connected to tinnitus onset, we also included a stress induction. No differences between the groups were found for interoceptive accuracy and sensibility. However, the tinnitus group tended to overestimate the occurrence of phasic activation. Loudness of the tinnitus was associated with reduced interoceptive performance under stress. Our results indicate that interoceptive sensibility and accuracy do not play a significant role in tinnitus. However, tinnitus might be associated with a tendency to overestimate physical changes.

Dissociation between Emotional Remapping of Fear and Disgust in Alexithymia

There is growing evidence that individuals are able to understand others' emotions because they "embody" them, i.e., re-experience them by activating a representation of the observed emotion within their own body. One way to study emotion embodiment is provided by a multisensory stimulation paradigm called emotional visual remapping of touch (eVRT), in which the degree of embodiment/remapping of emotions is measured as enhanced detection of near-threshold tactile stimuli on one's own face while viewing different emotional facial expressions. Here, we measured remapping of fear and disgust in participants with low (LA) and high (HA) levels of alexithymia, a personality trait characterized by a difficulty in recognizing emotions. The results showed that fear is remapped in LA but not in HA participants, while disgust is remapped in HA but not in LA participants. To investigate the hypothesis that HA might exhibit increased responses to emotional stimuli producing a heightened physical and visceral sensations, i.e., disgust, in a second experiment we investigated participants' interoceptive abilities and the link between interoception and emotional modulations of VRT. The results showed that participants' disgust modulations of VRT correlated with their ability to perceive bodily signals. We suggest that the emotional profile of HA individuals on the eVRT task could be related to their abnormal tendency to be focalized on their internal bodily signals, and to experience emotions in a "physical" way. Finally, we speculated that these results in HA could be due to a enhancement of insular activity during the perception of disgusted faces.

Alexithymic Trait, Painful Heat Stimulation, and Everyday Pain Experience

BACKGROUND

Alexithymia was found to be associated with a variety of somatic complaints, including somatoform pain symptoms. This study addressed the question of whether the different facets of alexithymia are related to responses in heat pain stimulation and its interrelations with levels of everyday pain as assessed by self-report.

METHODS

In the study, sensitivity to heat pain was assessed in 50 healthy female participants. Alexithymia facets were assessed by the Toronto Alexithymia Scale. Pain threshold and tolerance were determined using a testing the limits procedure. Participants, furthermore, rated subjective intensities and unpleasantness of tonic heat stimuli (45.5-47.5°C) on visual analog scales and on a questionnaire. Possible confounding with temperature sensitivity and mood was controlled. Everyday pain was assessed by self-report addressing everyday pain frequency, intensity, and impairment experienced over the last 2 months.

RESULTS

Main results were that the facets of alexithymia were differentially associated with pain perception. The affective scale "difficulties in describing feelings" was associated with hyposensitivity to pain as indicated by higher pain tolerance scores. Furthermore, everyday pain frequency was related to increased alexithymia values on the affective scale "difficulties in identifying feelings," whereas higher values on the cognitive alexithymia scale "externally oriented thinking" were related to lower pain impairment and intensity.

CONCLUSION

We conclude that the different facets of alexithymia are related to alternations in pain processing. Further research on clinical samples is necessary to elucidate whether different aspects of alexithymia act as a vulnerability factor for the development of pain symptoms.

Methodological recommendations for a heartbeat detection-based measure of interoceptive sensitivity

Heartbeat detection tasks are often used to measure cardiac interoceptive sensitivity-the ability to detect sensations from one's heart. However, there is little work to guide decisions on the optimum number of trials to use, which should balance reliability and power against task duration and participant burden. Here, 174 participants completed 100 trials of a widely used heartbeat detection task where participants attempt to detect whether presented tones occurred synchronously or asynchronously with their heartbeats. First, we quantified measurement reliability of the participant's accuracy derived from differing numbers of trials of the task using a correlation metric; we found that at least 40-60 trials were required to yield sufficient reliability. Next, we quantified power by simulating how the number of trials influenced the ability to detect a correlation between cardiac interoceptive sensitivity and other variables that differ across participants, including a variable measured from our sample (body mass index) as well as simulated variables of varying effect sizes. Using these simulations, we quantified the trade-offs between sample size, effect size, and number of trials in the heartbeat detection task such that a researcher can easily determine any one of these variables at given values of the other two variables. We conclude that using fewer than 40 trials is typically insufficient due to poor reliability and low power in estimating an effect size, although the optimal number of trials can differ by study.

The Relation of Alexithymic Traits to Affective Theory of Mind

Little research has focused on the contributors to adult theory of mind (ToM) even though there is reason to suspect individual differences in performance in neurotypical samples. Alexithymia, a term that references an impaired ability to attend to and verbally label emotions via ongoing introspection, is a useful construct through which to explore how socially relevant dimensions of emotion processing enable ToM. As 1 study has explored alexithymia vis-à-vis cognitive ToM, this study examined the relationships between facets of alexithymia and affective ToM while controlling for the potential confounds of empathy, verbal ability, and negative affect. A nonclinical sample of adults (N = 86) completed the Toronto Alexithymia Scale, the Reading the Mind in the Eyes Test, the Mehrabian and Epstein Scale of Emotional Empathy, the Profile of Mood States, and the Wechsler Abbreviated Scale of Intelligence. Hierarchical regression analysis showed that externally oriented thinking contributed unique variance to affective ToM, confirming an inverse relationship between alexithymia and affective ToM but highlighting the need to parse alexithymia into discrete facets when exploring its relevance to social cognition.

The relationships between interoception and alexithymic trait. The Self-Awareness Questionnaire in healthy subjects

Interoception is the basic process enabling evaluation of one's own bodily states. Several previous studies suggested that altered interoception might be related to disorders in the ability to perceive and express emotions, i.e., alexithymia, and to defects in perceiving and describing one's own health status, i.e., hypochondriasis. The main aim of the present study was to investigate the relationships between alexithymic trait and interoceptive abilities evaluated by the “Self-Awareness Questionnaire” (SAQ), a novel self-report tool for assessing interoceptive awareness. Two hundred and fifty healthy subjects completed the SAQ, the Toronto Alexithymia Scale-20 items (TAS-20), and a questionnaire to assess hypochondriasis, the Illness Attitude Scale (IAS). The SAQ showed a two-factor structure, with good internal consistency (Cronbach's alpha = 0.88). We observed significant direct correlations between SAQ, TAS-20 and two of its subscales, and the IAS. Regression analysis confirmed that the difficulty in identifying and expressing emotions is significantly related with awareness for one's own interoceptive feelings and with a tendency to misinterpret and amplify bodily sensations. From a clinical point of view, the assessment of interoceptive awareness by the SAQ could be pivotal in evaluating several psychopathological conditions, such as the somatoform disorders.

Alexithymia modulates the experience of the rubber hand illusion

Alexithymia is associated with lower awareness of emotional and non-emotional internal bodily signals. However, evidence suggesting that alexithymia modulates body awareness at an external level is scarce. This study aimed to investigate whether alexithymia is associated with disrupted multisensory integration by using the rubber hand illusion task. Fifty healthy individuals completed the Toronto Alexithymia Scale and underwent the rubber hand illusion measure. In this measure, one watches a rubber hand being stroked synchronously or asynchronously with one’s own hand, which is hidden from view. Compared to the asynchronous stimulation, the synchronous stimulation results in the illusion that the rubber hand and the participant’s hand are closer together than they really are and that the rubber hand belongs to them. Results revealed that higher levels of alexithymia are associated with a lower ownership illusion over the rubber hand. In conclusion, our findings demonstrate that high alexithymia scorers integrate two simultaneous sensory and proprioceptive events into a single experience (lower multisensory integration) to a lesser extent than low alexithymia scorers. Higher susceptibility to the illusion in high alexithymia scorers may indicate that alexithymia is associated with an abnormal focus of one’s own body.

The association between alexithymia as assessed by the 20-item Toronto Alexithymia Scale and depression: A meta-analysis

Patients with depression exhibit high rates of alexithymia, representing a major public health concern. We sought to examine relationships between depression severity and alexithymia as assessed by the Toronto Alexithymia Scale (TAS-20) and the TAS-20 subscales of difficulty identifying feelings (DIF), difficulty describing feelings (DDF), and externally oriented thinking (EOT). Potentially relevant studies were obtained independently by two reviewers. Chi-square statistics based on the Q-test and I(2) index assessed statistical heterogeneity between studies. Subgroup analyses were mainly used to explore sources of heterogeneity. Begg׳s test and Duval and Tweedie' trim and fill were used to assess potential publication bias. Altogether, 3572 subjects from 20 study groups across 19 studies were included. Medium relationships were observed between depression and TAS-total score (TAS-TS), DIF, and DDF. There was also a weak relationship between EOT and depression. Subgroup analyses showed a stronger correlation between TAS-TS and depression assessed by self-reported tools than that assessed by the Hamilton Rating Scale for Depression. The heterogeneity significantly decreased only in the subgroup analysis by depression tool. We conclude that alexithymia, as assessed by the TAS-20 and its subscales DIF and DDF, is closely related to depression. These relationships were affected by depression measurement tools.

Neural activity during interoceptive awareness and its associations with alexithymia-An fMRI study in major depressive disorder and non-psychiatric controls

OBJECTIVE

Alexithymia relates to difficulties recognizing and describing emotions. It has been linked to subjectively increased interoceptive awareness (IA) and to psychiatric illnesses such as major depressive disorder (MDD) and somatization. MDD in turn is characterized by aberrant emotion processing and IA on the subjective as well as on the neural level. However, a link between neural activity in response to IA and alexithymic traits in health and depression remains unclear.

METHODS

A well-established fMRI task was used to investigate neural activity during IA (heartbeat counting) and exteroceptive awareness (tone counting) in non-psychiatric controls (NC) and MDD. Firstly, comparing MDD and NC, a linear relationship between IA-related activity and scores of the Toronto Alexithymia Scale (TAS) was investigated through whole-brain regression. Secondly, NC were divided by median-split of TAS scores into groups showing low (NC-low) or high (NC-high) alexithymia. MDD and NC-high showed equally high TAS scores. Subsequently, IA-related neural activity was compared on a whole-brain level between the three independent samples (MDD, NC-low, NC-high).

RESULTS

Whole-brain regressions between MDD and NC revealed neural differences during IA as a function of TAS-DD (subscale difficulty describing feelings) in the supragenual anterior cingulate cortex (sACC; BA 24/32), which were due to negative associations between TAS-DD and IA-related activity in NC. Contrasting NC subgroups after median-split on a whole-brain level, high TAS scores were associated with decreased neural activity during IA in the sACC and increased insula activity. Though having equally high alexithymia scores, NC-high showed increased insula activity during IA compared to MDD, whilst both groups showed decreased activity in the sACC.

CONCLUSIONS

Within the context of decreased sACC activity during IA in alexithymia (NC-high and MDD), increased insula activity might mirror a compensatory mechanism in NC-high, which is disrupted in MDD.

The Contributions of Interoceptive Awareness to Cognitive and Affective Facets of Body Experience

Experience of one’s own body relies on signals arising within the body as well as on exteroceptive information, and on appraisal of cognitive and affective aspects of these signals. The present study investigated the impact of sensitivity to internal signals, that is, interoceptive awareness, on interindividual differences in cognitive and emotional aspects of body experience. Subjects with accurate (n = 30) versus poor (n = 30) interoceptive awareness, classified via a heartbeat perception task, completed the Body Consciousness Questionnaire and the Body Appraisal Inventory. Possible effects of emotional state on body experience were controlled for using measures of mood and anxiety. While the groups did not differ in their emotional state, individuals with accurate cardiac interoceptive awareness exhibited higher subjective sensitivity to bodily sensations and a more positive body image, characterized by stronger body-related self-confidence, greater satisfaction with physical appearance, greater perceived bodily self-control, as well as reduced hypochondriacal concerns, sexual discontent, and shame. The present findings extend earlier research on the importance of perception of physical cues for emotion, cognition, and behavior regulation. Our results underline the contribution of interoceptive information to body experience, where interindividual differences in the accessibility of such information modulate cognitive and affective facets of body image.

Towards multiple interactions of inner and outer sensations in corporeal awareness

Under normal circumstances, different inner- and outer-body sources are integrated to form coherent and accurate mental experiences of the state of the body, leading to the phenomenon of corporeal awareness. How these processes are affected by changes in inner and outer inputs to the body remains unclear. Here, we aim to present empirical evidence in which people with a massive sensory and motor disconnection may continue to experience feelings of general body state awareness without complete control of their inner and outer states. In these clinical populations, the activity of the neural structures subserving inner and outer body processing can be manipulated and tuned by means of body illusions that are usually based on multisensory stimulation. We suggest that a multisensory therapeutic approach could be adopted in the context of therapies for patients suffering from deafferentation and deefferentation. In this way, these individuals could regain a more complete feeling and control of the sensations they experience, which vary widely depending on their neurological condition.

Differential changes in self-reported aspects of interoceptive awareness through 3 months of contemplative training

Interoceptive body awareness (IA) is crucial for psychological well-being and plays an important role in many contemplative traditions. However, until recently, standardized self-report measures of IA were scarce, not comprehensive, and the effects of interoceptive training on such measures were largely unknown. The Multidimensional Assessment of Interoceptive Awareness (MAIA) questionnaire measures IA with eight different scales. In the current study, we investigated whether and how these different aspects of IA are influenced by a 3-months contemplative intervention in the context of the ReSource project, in which 148 subjects engaged in daily practices of "Body Scan" and "Breath Meditation." We developed a German version of the MAIA and tested it in a large and diverse sample (n = 1,076). Internal consistencies were similar to the English version (0.56-0.89), retest reliability was high (rs: 0.66-0.79), and the MAIA showed good convergent and discriminant validity. Importantly, interoceptive training improved five out of eight aspects of IA, compared to a retest control group. Participants with low IA scores at baseline showed the biggest changes. Whereas practice duration only weakly predicted individual differences in change, self-reported liking of the practices and degree of integration into daily life predicted changes on most scales. Interestingly, the magnitude of observed changes varied across scales. The strongest changes were observed for the regulatory aspects of IA, that is, how the body is used for self-regulation in daily life. No significant changes were observed for the Noticing aspect (becoming aware of bodily changes), which is the aspect that is predominantly assessed in other IA measures. This differential pattern underscores the importance to assess IA multi-dimensionally, particularly when interested in enhancement of IA through contemplative practice or other mind-body interventions.

Interoceptive sensitivity, body image dissatisfaction, and body awareness in healthy individuals

Relationships among interoceptive sensitivity (IS), body image dissatisfaction, body mass index (BMI), and self-reported body awareness were investigated in a cross-sectional study. Eighty-two Norwegian high school students and 70 Hungarian undergraduate university students participated in the study. Subjects completed two questionnaires (Body Image Ideals Questionnaire - BIQ; Body Awareness Questionnaire - BAQ) followed by the assessment of interoceptive sensitivity using the Mental Tracking Method (MTM). An inverse, medium-level relationship between body image dissatisfaction and IS was found in both the Norwegian and the Hungarian samples. The relationships between IS and self-reported body awareness, and between body image dissatisfaction and BMI were uniformly non-significant in both samples. Predictors of body image dissatisfaction were resting heart rate, gender, and IS in the regression analysis after controlling for BMI, age, and nationality. The negative relationship between IS and body image dissatisfaction described in patients with anorexia nervosa also exists in healthy individuals. There is no direct connection between IS and self-reported body awareness.

Recognition of facially expressed emotions in patients with fibromyalgia syndrome

The study investigated the ability to identify facially expressed emotions in fibromyalgia syndrome (FMS) and its association with clinical parameters. Thirty-five FMS patients and 35 healthy controls accomplished a face recognition task. Additionally, pain severity, alexithymia, depression, anxiety, psychiatric co-morbidity and medication use were assessed. The patients displayed reduced task performance in terms of more misclassifications of emotional expressions than controls. Pain severity, alexithymia, depression and anxiety were inversely related to recognition performance, with pain severity accounting for the largest portion of test score variance. Psychiatric co-morbidity and medication had no impact on performance. The study documented impaired emotion recognition in FMS, which may contribute to the interpersonal difficulties and reduced social functioning related to this condition. As potential mechanisms mediating the occurrence of the deficits, altered affective processing due to interoceptive impairment as well as interference of central nervous nociceptive activity with cognitive and emotional processing are discussed.

Conflict adaptation is predicted by the cognitive, but not the affective alexithymia dimension

Stimulus-induced response conflict (e.g., in Simon or Stroop tasks) is often reduced after conflict trials—the Gratton effect. It is generally assumed that this effect is due to a strengthening of the representation of the current intention or goal, which in turn increases the degree of stimulus and/or response control. Recent evidence suggests that the motivational signal driving the Gratton effect might be affective in nature. If so, individual differences in either the strength of affective signals and/or the ability to interpret such signals might explain individual differences in cognitive-control adjustments as reflected in the Gratton effect. We tested this hypothesis by relating individual sizes of the Gratton effect in a Simon task to scores on the affective and the cognitive dimension of the Bermond/Vorst Alexithymia Questionnaire (BVAQ)—which we assumed to assess individual differences in affective-signal strength and ability to interpret affective signals, respectively. Results show that the cognitive, but not the affective dimension predicted control adjustment, while the accuracy of heartbeat detection was only (and only weakly) related to online control. This suggests that the motivation to fine-tune one's cognitive-control operations is mediated by, and may depend on one's ability to interpret one's own affective signals.

Eye contact elicits bodily self-awareness in human adults

Eye contact is a typical human behaviour known to impact concurrent or subsequent cognitive processing. In particular, it has been suggested that eye contact induces self-awareness, though this has never been formally proven. Here, we show that the perception of a face with a direct gaze (that establishes eye contact), as compared to either a face with averted gaze or a mere fixation cross, led adult participants to rate more accurately the intensity of their physiological reactions induced by emotional pictures. Our data support the view that bodily self-awareness becomes more acute when one is subjected to another's gaze. Importantly, this effect was not related to a particular arousal state induced by eye contact perception. Rejecting the arousal hypothesis, we suggest that eye contact elicits a self-awareness process by enhancing self-focused attention in humans. We further discuss the implications of this proposal.

Biofeedback-based training for stress management in daily hassles: an intervention study

BACKGROUND

The day-to-day causes of stress are called daily hassles. Daily hassles are correlated with ill health. Biofeedback (BF) is one of the tools used for acquiring stress-coping skills. However, the anatomical correlates of the effects of BF with long training periods remain unclear. In this study, we aimed to investigate this.

METHODS

PARTICIPANTS WERE ASSIGNED RANDOMLY TO TWO GROUPS: the intervention group and the control group. Participants in the intervention group performed a biofeedback training (BFT) task (a combination task for heart rate and cerebral blood flow control) every day, for about 5 min once a day. The study outcomes included MRI, psychological tests (e.g., Positive and Negative Affect Schedule, Center for Epidemiologic Studies Depression Scale, and Brief Job Stress Questionnaire), and a stress marker (salivary cortisol levels) before (day 0) and after (day 28) the intervention.

RESULTS

We observed significant improvements in the psychological test scores and salivary cortisol levels in the intervention group compared to the control group. Furthermore, voxel-based morphometric analysis revealed that compared to the control group, the intervention group had significantly increased regional gray matter (GM) volume in the right lateral orbitofrontal cortex, which is an anatomical cluster that includes mainly the left hippocampus, and the left subgenual anterior cingulate cortex. The GM regions are associated with the stress response, and, in general, these regions seem to be the most sensitive to the detrimental effects of stress.

CONCLUSIONS

Our findings suggest that our BFT is effective against the GM structures vulnerable to stress.

Striking discrepancy of anomalous body experiences with normal interoceptive accuracy in depersonalization-derealization disorder

Background

Disembodiment is a core feature of depersonalization disorder (DPD). Given the narratives of DPD patients about their disembodiment and emotional numbing and neurobiological findings of an inhibition of insular activity, DPD may be considered as a mental disorder with specific impairments of interoceptive awareness and body perception.

Methods

We investigated cardioceptive accuracy (CA) of DPD patients (n = 24) as compared to healthy controls (n = 26) with two different heartbeat detection tasks (“Schandry heartbeat counting task” and “Whitehead heartbeat discrimination task”). Self-rated clearness of body perception was measured by questionnaire.

Results

Contrary to our hypothesis, DPD patients performed similarly to healthy controls on the two different heartbeat detection tasks, and they had equal scores regarding their self-rated clearness of body perception. There was no correlation of the severity of “anomalous body experiences” and depersonalization with measures of interoceptive accuracy. Only among healthy controls CA in the Schandry task was positively correlated with self-rated clearness of body perception. Depersonalization was unrelated to severity of depression or anxiety, while depression and anxiety were highly correlated. Anxiety and depression did not modify the associations of depersonalization with interoceptive accuracy.

Conclusions

Our main findings highlight a striking discrepancy of normal interoception with overwhelming experiences of disembodiment in DPD. This may reflect difficulties of DPD patients to integrate their visceral and bodily perceptions into a sense of their selves. This problem may be considered an important target for psychotherapeutic treatment approaches.