Understanding implicit and explicit learning in adolescents with and without anorexia nervosa

Examining anxious temperament in anorexia nervosa: Behavioural inhibition and intolerance of uncertainty and their contribution to trait anxiety in adolescents with anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) is a serious and complex psychiatric disorder yet treatment results are suboptimal. Insight into the etiology of this illness is much needed. Research highlights the implication of anxiety-related traits in the development and maintenance of AN. This study investigates firstly, behavioural inhibition and intolerance for uncertainty (IU) in adolescents with and without AN, and secondly relations between these traits.

METHODS

In a cross-sectional study, 165 adolescent girls (AN = 94, HC = 71) completed questionnaires measuring behavioural inhibition, IU and trait anxiety. ANOVAs tested differences between AN and HC groups, and mediation models with IU as a mediator between behavioural inhibition and trait anxiety were run.

RESULTS

AN adolescents reported significantly higher levels of behavioural inhibition, IU and trait anxiety compared to their peers. In both AN and HC, a direct and a total effect of behavioural inhibition on trait anxiety was found. However, only in the AN group IU partially mediated the relation between behavioural inhibition and trait anxiety.

LIMITATIONS

Data is cross-sectional and longitudinal studies are required. A mean illness duration of nearly 2 years may mean early effects of malnourishment and habituation and future studies should include patients with shorter illness duration.

CONCLUSIONS

Results highlight that behavioural inhibition and IU may contribute to anxiety in AN whilst their peers may have developed better executive and social-emotional skills to manage uncertainty. Adolescents with AN may benefit from interventions targeting behavioural inhibition and IU.

Impaired implicit learning in adults with anorexia nervosa

OBJECTIVE

Cognitive alterations play an important role in the pathophysiology and treatment of anorexia nervosa (AN). Previous studies suggest that some implicit learning processes may be inhibited in AN. However, this has not yet been fully explored. The purpose of this study is to analyze implicit learning in patients with AN in comparison to healthy controls.

METHODS

In this pilot-study, a total of 21 patients diagnosed with AN and 21 matched controls were administered the weather prediction task (WPT), a probabilistic implicit category learning task that consists of two sub-variants. During the feedback (FB) version of the task, participants learn associations between tarot cards and weather outcomes via an operant learning model through which they receive immediate FB on their answers, whereas during the paired associate (PA) variant, participants are directly asked to memorize given associations.

RESULTS

AN patients showed selective impairment on the FB task where they scored significantly lower both in comparison to controls (p = .001) who completed the same task and when compared to their own performance on the PA variant (p = .006). Clinical measures showed no significant correlations with test scores.

DISCUSSION

Our results demonstrate implicit FB learning deficiencies in adult patients with AN. These impairments may have an impact on the effect of psychotherapeutic interventions and could partially explain the lack of treatment response in AN. Further studies are necessary to derive when and through which mechanisms these alterations originate, and to what extent they should be considered during treatment of the disorder.

PUBLIC SIGNIFICANCE

Cognitive impairments pose a challenge in the management of anorexia nervosa. Improved comprehension of cognitive alterations could lead to a greater understanding of the disease and adaptation of psychotherapeutic treatments. In this study, we found that implicit feedback learning in anorexia nervosa is impaired compared to healthy controls. This could indicate the necessity of treatment adaptations in the form of therapy tools without feedback and a larger focus on psychoeducation.

Brain functional alterations in patients with anorexia nervosa: A meta-analysis of task-based functional MRI studies

The goal of this study was to discern the neural activation patterns associated with anorexia nervosa (AN) in response to tasks related to body-, food-, emotional-, cognitive-, and reward- processing. A meta-analysis was performed on task-based fMRI studies, revealing that patients with AN showed increased activity in the left superior temporal gyrus and bilaterally in the ACC during a reward-related task. During cognitive-related tasks, patients with AN also showed increased activity in the left superior parietal gyrus, right middle temporal gyrus, but decreased activity in the MCC. Additionally, patients with AN showed increased activity bilaterally in the cerebellum, MCC, and decreased activity bilaterally in the bilateral precuneus/PCC, right middle temporal gyrus, left ACC when they viewed food images. During emotion-related tasks, patients with AN showed increased activity in the left cerebellum, but decreased activity bilaterally in the striatum, right mPFC, and right superior parietal gyrus. Patients with AN also showed increased activity in the right striatum and decreased activity in the right inferior temporal gyrus and bilaterally in the mPFC during body-related tasks. The present meta-analysis provides a comprehensive overview of the patterns of brain activity evoked by task stimuli, thereby augmenting the current comprehension of the pathophysiology in AN.

Sensory processing in children and adolescents shortly after the onset of anorexia nervosa: a pilot study

BACKGROUND

Alterations in sensory processing, such as vision, taste, and interoceptive sensation, have been reported in adult anorexia nervosa (AN). Whether these symptoms are traits, states, or "scars" due to chronic starvation has not been fully established. Based on the hypothesis that alterations in sensory processing also occur in adolescent AN in the early stages of the disease, the present study was conducted using both self-administered and parent-administered sensory processing questionnaires.

METHODS

Children and adolescents with anorexia nervosa treated at a single tertiary eating disorder treatment center in Japan (AN group) and female junior high school students attending a public junior high school in Saitama Prefecture, Japan (healthy control group: HC group) were included in the study. The Sensory Profile (SP) and Adult/Adolescent Sensory Profile (AASP) were administered to the participants and their caregivers. In addition, we collected demographic data and administered the Children's Eating Attitude Test and Autism-Spectrum Quotient Children's version.

RESULTS

Seventeen children and adolescents were enrolled in the AN group, and 63 were enrolled in the HC group. There was no statistically significant difference between the AN and HC groups in the quadrant scores of the AASP. In the SP, the Sensory Avoiding score and the Emotional/Social response score were higher in the AN group than in the HC group.

CONCLUSION

From the parents' point of view, the patient avoids unexpected sensory stimuli, but the patients are unaware of their own avoiding behavior in the early stages of the disease. The results suggest that sensory sensitivity in AN may be a "scar" symptom due to chronic starvation and a state symptom. Longitudinal studies from shortly after the onset with larger sample sizes are needed to gain insight into the dynamic relation between sensory processing and eating disorder pathology.