Neural correlates of eating disorders: translational potential

Abnormal Spontaneous Regional Brain Activity in Young Patients With Anorexia Nervosa

OBJECTIVE

Functional magnetic resonance imaging (fMRI) studies have repeatedly shown alterations in patients with anorexia nervosa (AN). These alterations might be driven by baseline signal characteristics such as the (fractional) amplitude of low frequency fluctuations (fALFF/ALFF), as well as regional signal consistency (ie, regional homogeneity [ReHo]) within circumscribed brain regions. Previous studies have also demonstrated gray matter (pseudo-) atrophy in underweight individuals with AN. Here we study fALFF/ALFF and ReHo in predominantly adolescent patients with AN, while taking gray matter changes into consideration.

METHOD

Resting state fMRI data were acquired from a sample of 148 female volunteers: 74 underweight patients with AN and 74 age-matched female healthy controls (HC).

RESULTS

Group differences for fALFF and ReHo measures were found in several AN-relevant brain regions, including networks related to cognitive control, habit formation, and the ventral visual stream. Furthermore, the magnitude of correlation between gray matter volume/thickness and fALFF and ReHo were reduced in AN compared to HC.

CONCLUSION

Abnormal local resting state characteristics in AN-related brain-networks as well as reduced structure-function relationships may help to explain previously reported task-related and classical resting state neural alterations in underweight AN. Patients with AN may serve as a valuable population for investigating dynamic changes in the relationships between brain structure and function.

Assessment of Family Functioning and Eating Disorders - The Mediating Role of Self-Esteem

The aim of the study was to measure whether people at increased risk for eating disorders (EDs) and people without an increased risk of EDs differ from each other in the assessment of family functioning (FF) and self-esteem (SE) dimensions. Moreover, the correlations between FF, EDs, and SE were verified, looking for the mediating role of SE in the context of the FF and EDs. The research was conducted on the group of 160 people aged from 18 to 47 years, including 74 people at increased risk for EDs. We used: The Family APGAR (Adaptability, Partnership, Growth, Affection, and Resolve); The SCOFF Questionnaire; The Multidimensional Self-Esteem Inventory, MSEI. Analyses indicate that the compared groups differ significantly in terms of EDs, assessment of FF, and all components of SE, in such a way that people without an increased risk of EDs are characterized by a more positive assessment of FF and higher SE in all its dimensions. All SE dimensions, except defensive high SE, are mediators in the relationship of FF with EDs. In therapeutic interactions, it is worth focusing on the SE dimensions, as they are one of the mediation elements in the relationship between the assessment of FF and EDs.

The improvement in neurocognitive functioning in anorexia nervosa adolescents throughout the integrative model of psychotherapy including cognitive remediation therapy

BACKGROUND

Patients with anorexia nervosa (AN) experience difficulties in neurocognitive functioning in the acute phase of illness which might be related to clinical presentation, but also in the apparently remitted state after weight recovery. Among the most commonly reported persistent deficits is cognitive inflexibility, which can be interpreted as a vulnerability trait or a "neuropsychological scar" reflecting the detrimental effect of prolonged semi-starvation in patients with a long duration of illness. Studies of adolescent samples with a relatively short clinical course may enable avoiding the effect of prolonged illness and help to determine whether neuropsychological deficits are trait or state dependent. The aim of this study is to assess cognitive functioning in adolescents with AN before and after the inpatient treatment programme, including cognitive remediation therapy (CRT).

METHODS

Forty-seven adolescent female inpatients with AN diagnosed according to DSM-5 and fifty healthy female adolescents matched for the education level and age were recruited. The patients underwent a multimodal treatment including a ten-week CRT. The standardized and cross-validated neuropsychological (Trail Making Test - TMT A and B, Color-Word Stroop Task - CWST, Ruff Figural Fluency Test - RFFT) and clinical measurements (Beck Depression Inventory - BDI, Eating Attitude Test - EAT-26, Yale-Brown Obsessive Compulsive Scale - Y-BOCS) were used to assess both clinical (in the acute phase and after partial weight recovery) and control subjects.

RESULTS

Initially, AN patients performed significantly worse compared to the controls, but afterwards, inpatient treatment improvement was noted on all examined measures. In a few subtests (TMT, CWST) performance of AN patients after the programme was still significantly poorer than in HC.

CONCLUSIONS

Cognitive inflexibility in adolescent AN patients, as measured with TMT, CWST, and RFFT tends to improve after therapy. Nevertheless, a few neuropsychological subtests which did not show complete normalization may warrant attention in subsequent studies. Further research including control intervention is needed to conclude whether CRT intervention affects the outcome.

Development of a methodology to combine fMRI and EMG to measure emotional responses in patients with anorexia nervosa

OBJECTIVE

Individuals with eating disorders are theorized to have basic impairments in affective appraisal and social-emotional processing that contribute to pathogenesis of the disease. We aimed to determine if facial electromyography could be used to discriminate between happy and disgust emotions during simultaneous acquisition of an fMRI BOLD sequence in efforts to establish a novel tool for investigating emotion-driven hypotheses about eating pathology. In line with standards for rigor and reproducibility, we provide detailed protocols and code to support each step of this project.

METHOD

Sixteen adolescents with low-weight eating disorders viewed emotional faces (Happy or Disgust) and were asked to mimic their facial expression during simultaneous BOLD and EMG (Corrugator supercilli, Lavator lavii, Zygomaticus major) acquisition. Trials were repeated with the scanner off and again with scanner on (i.e., fatigue).

RESULTS

The Levator and Zygomaticus activation patterns discriminated disgust and happy faces successfully. The pattern held between scanner on and off conditions, but muscle activation attenuated in the Fatigue condition, especially for the Zygomaticus.

DISCUSSION

Simultaneous fMRI-EMG is a new tool capable of discriminating specific emotions based on muscle activation patterns and can be leveraged to answer emotion-driven hypotheses about clinical populations characterized by difficulty labeling or processing emotions.

Advances in the treatment of anorexia nervosa: a review of established and emerging interventions

BACKGROUND

Anorexia nervosa (AN) is a disabling, deadly and costly mental disorder. Until recently, treatment recommendations were based on expert opinion and limited evidence. The aim of this systematic review is to synthesise recent evidence on established and emerging AN treatments and to forecast trends for future developments.

METHODS

We systematically review trials of established treatments and associated process outcome studies from the last 5 years, published since a previous review in this journal. 'Established' treatments were those that are widely used in AN, recommended by guidelines and/or have been tested in at least one large randomised controlled trial. Secondly, we summarise emerging treatments for AN, i.e. those that have only been (or are currently being) tested in proof-of concept, feasibility or pilot trials.

RESULTS

We identified 19 published trials of established treatments (15 of high or moderate quality), mostly assessing psychological therapies (n = 17). We also found 11 published trials of emerging treatments, and a total of 34 registered, as yet unpublished trials. Promising emerging treatments include cognitive remediation therapy, exposure therapy and non-invasive neuromodulation.

CONCLUSIONS

Evidence generation on the treatment of AN has dramatically accelerated, with our understanding of the role of family-based approaches for adolescents more nuanced and a range of psychological approaches available for the treatment of adults. Evidence on emerging treatments and from forthcoming trials suggests that there is a shift towards more targeted brain-based interventions. Future studies need to focus on elucidating mechanisms of action of treatments and what works best for whom.

Mentalization and the left inferior frontal gyrus and insula

OBJECTIVE

To determine if an interpersonal attribution bias associated with self-perception, the externalizing bias, was related to neural activations during mentalization.

METHODS

A functional magnetic resonance imaging task involving verbal appraisals measured neural activations when thinking about oneself and others in 59 adults, including healthy women as well as women with and recovered from anorexia nervosa. Whole-brain regressions correlated brain function during mentalization with the externalizing bias measured using the Internal, Personal, and Situational Attributions Questionnaire.

RESULTS

Women with anorexia nervosa had a lower externalizing bias, demonstrating a tendency to self-attribute more negative than positive social interactions, unlike the other groups. The externalizing bias was correlated with activation of the left inferior frontal gyrus and posterior insula, when comparing thinking about others evaluating oneself with direct self-evaluation.

DISCUSSION

Externalizing biases may provide an office-based assay reflecting neurocognitive disturbances in social self-perception that are common during anorexia nervosa.

Blunted neural response to implicit negative facial affect in anorexia nervosa

BACKGROUND

People with anorexia nervosa (AN) have difficulties in a wide range of social-emotional processes. Previous work suggests atypical involvement of the prefrontal cortex (PFC), amygdala, insula, and fusiform gyri during social-emotional processing in AN.

METHODS

Twenty women with AN and twenty healthy comparison (HC) women were presented with happy, fearful, and neutral faces during a functional magnetic resonance imaging study. Group differences were investigated in the following regions of interest: lateral PFC, amygdala, insula, and fusiform gyri.

RESULTS

The HC participants showed significantly increased recruitment of the ventrolateral PFC and amygdala in the fearful > neutral contrast relative to the AN participants. The AN participants showed a significantly increased recruitment of a small cluster in the right posterior insula in the happy > neutral contrast.

CONCLUSIONS

These findings are in line with the hypothesis that people with AN have a blunted response to negative and atypical exaggerated response to positive emotionally provoking stimuli.

FMRI Study of Neural Responses to Implicit Infant Emotion in Anorexia Nervosa

Difficulties in social–emotional processing have been proposed to play an important role in the development and maintenance of anorexia nervosa (AN). Few studies, thus far, have investigated neural processes that underlie these difficulties, including processing emotional facial expressions. However, the majority of these studies have investigated neural responses to adult emotional display, which may be confounded by elevated sensitivity to social rank and threat in AN. Therefore, the aim of this study was to investigate the neural processes underlying implicit processing of positively and negatively valenced infant emotional display in AN. Twenty-one adult women with AN and twenty-six healthy comparison (HC) women were presented with images of positively valenced, negatively valenced, and neutral infant faces during a fMRI scan. Significant differences between the groups in positive > neutral and negative > neutral contrasts were investigated in a priori regions of interest, including the bilateral amygdala, insula, and lateral prefrontal cortex (PFC). The findings revealed that the AN participants showed relatively increased recruitment while the HC participants showed relatively reduced recruitment of the bilateral amygdala and the right dorsolateral PFC in the positive > neutral contrast. In the negative > neutral contrast, the AN group showed relatively increased recruitment of the left posterior insula while the HC groups showed relatively reduced recruitment of this region. These findings suggest that people with AN may engage in implicit prefrontal down-regulation of elevated limbic reactivity to positively social–emotional stimuli.