Cognitive style of patients with anorexia nervosa and bulimia nervosa

Anorexia Nervosa, Body Image Perception and Virtual Reality Therapeutic Applications: State of the Art and Operational Proposal

Anorexia Nervosa (AN) patients exhibit distorted body representation. The purpose of this study was to explore studies that analyze virtual reality (VR) applications, related to body image issues, to propose a new tool in this field. We conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, EMBASE, Scopus, and Web of Science databases were explored; the review included 25 studies. Research has increased over the last five years. The selected studies, clinical observational studies (n = 16), mostly concerning patients' population with AN (n = 14) or eating disorders (EDs) diagnosis, presented multiple designs, populations involved, and procedures. Some of these studies included healthy control groups (n = 7). Studies on community sample populations were also selected if oriented toward clinical applications (n = 9). The VR technologies in the examined period (about 20 years) have evolved significantly, going from very complex and bulky systems, requiring very powerful computers, to agile systems. The advent of low-cost VR devices has given a big boost to research works. Moreover, the operational proposal that emerges from this work supports the use of biofeedback techniques aimed at evaluating the results of therapeutic interventions in the treatment of adolescent patients diagnosed with AN.

Short-Term Fasting Selectively Influences Impulsivity in Healthy Individuals

Previous research has shown that short-term fasting in healthy individuals is associated with changes in risky decision-making. The current experiment was designed to examine the influence of short-term fasting in healthy individuals on four types of impulsivity: reflection impulsivity, risky decision-making, delay aversion, and action inhibition. Participants were tested twice, once when fasted for 20 h, and once when satiated. Participants demonstrated impaired action inhibition when fasted; committing significantly more errors of commission during a food-related Affective Shifting Task. Participants also displayed decreased reflection impulsivity when fasted, opening significantly more boxes during the Information Sampling Task (IST). There were no significant differences in performance between fasted and satiated sessions for risky decision-making or delay aversion. These findings may have implications for understanding eating disorders such as Bulimia Nervosa (BN). Although BN has been characterized as a disorder of poor impulse control, inconsistent findings when comparing individuals with BN and healthy individuals on behavioral measures of impulsivity question this characterization. Since individuals with BN undergo periods of short-term fasting, the inconsistent findings could be due to differences in the levels of satiation of participants. The current results indicate that fasting can selectively influence performance on the IST, a measure of impulsivity previously studied in BN. However, the results from the IST were contrary to the original hypothesis and should be replicated before specific conclusions can be made.

Neuropsychology of eating disorders: 1995-2012

Eating disorders are considered psychiatric pathologies that are characterized by pathological worry related to body shape and weight. The lack of progress in treatment development, at least in part, reflects the fact that little is known about the pathophysiologic mechanisms that account for the development and persistence of eating disorders. The possibility that patients with eating disorders have a dysfunction of the central nervous system has been previously explored; several studies assessing the relationship between cognitive processing and certain eating behaviors have been conducted. These studies aim to achieve a better understanding of the pathophysiology of such diseases. The aim of this study was to review the current state of neuropsychological studies focused on eating disorders. This was done by means of a search process covering three relevant electronic databases, as well as an additional search on references included in the analyzed papers; we also mention other published reviews obtained by handsearching.

Decision-making and planning in full recovery of anorexia nervosa

OBJECTIVE

Based on findings of persisting neuropsychological impairments in women recovered from anorexia nervosa (rec AN), this study examined decision-making and planning, for achieving a desired goal, as central executive functions in a large sample of rec AN. The definition of recovery included physiological, behavioral, and psychological variables.

METHOD

A total of 100 rec AN women were compared to 100 healthy women, 1:1 matched for age and educational level. Decision-making was assessed with the Iowa Gambling Task and planning with the Tower of London. Expert interviews and self-ratings were used for assessing the inclusion/exclusion criteria and control variables.

RESULTS

Compared to healthy controls, rec AN women were better in decision-making and worse in planning even after considering control variables.

DISCUSSION

This study does not support results from other studies showing that rec AN participants perform better in decision-making. Results from this study show that planning is impaired even after full recovery from AN.

Measuring state trait properties of detail processing and global integration ability in eating disorders

OBJECTIVES

Women with eating disorders (EDs) are reported to have strengths in local or detailed information processing and difficulties with coherence or global processing/integration.

METHODS

This study aimed to replicate these findings and additionally explore a global integration task which has not previously been reported for an ED group, the Fragmented Pictures Task (FPT). Two hundred and twenty-two women (50 with anorexia nervosa (AN), 48 with bulimia nervosa (BN), 35 recovered from AN and 89 controls (HC)) completed the Rey-Osterrieth Complex Figure Task (RCFT) to measure global/local processing strategies, the Group Embedded Figures Task (GEFT) to measure local processing and the FPT to measure global integration.

RESULTS

Superior detail processing skills (GEFT) and a tendency to utilise detail processing strategies (RCFT) were associated with having AN, BN and being in recovery from AN. Global integration difficulties (FPT) were only observed in acute AN, whereas participants in the BN and recovered group performed similarly to HCs.

CONCLUSIONS

People currently ill with, and recovered from EDs are skilled at detail processing. The acute phase of AN is associated with difficulties in global integration.

Assessment of executive functions in obese individuals with binge eating disorder

OBJECTIVE: The aim of this study was to assess executive functions of obese individuals with binge eating disorder. METHOD: Thirty-eight obese individuals with binge eating disorder were compared to thirty-eight obese controls without binge eating disorder in terms of their executive functions. All individuals were assessed using the following instruments: Digit Span, Trail Making Tests A and B, Stroop Test and the Wisconsin Card Sorting Test. In addition, four subtests from the Behavioral Assessment of the Dysexecutive Syndrome Battery were also used, namely the Zoo Map Test, the Modified Six Elements Test, the Action Program Test and the Rule Shift Cards Test. RESULTS: When compared to obese controls, obese individuals with binge eating disorder presented significant impairment in the following tests: Digit Span backward, Zoo Map Test, Modified Six Elements Test, and Action Program Test. Subjects with binge eating disorder also showed significant more set shifting and perseverative errors in the Wisconsin Card Sorting Test. In other measures such as the Digit Span Forward, the Trail Making Test, the Stroop Test and the Rule Shift Cards Test, obese subjects with binge eating disorder did not differ significantly from obese subjects without binge eating disorder. CONCLUSION: These results suggest that, in the present sample, obese individuals with binge eating disorder presented executive deficits, especially impairments relating to problem-solving, cognitive flexibility and working memory.

Preliminary evidence for a role for impulsivity in cognitive disinhibition in bulimia nervosa

The present study investigated cognitive disinhibition in bulimia nervosa (BN) and examined whether impulsivity could account for this neuropsychological deficiency. Inhibitory processing of 13 women with BN (16-29 years) was compared against that of 13 healthy control participants matched for age, education, and socioeconomic status on a battery of widely used tasks: Stroop task, Haylings sentence completion test, excluded letter fluency, and Matching Familiar Figures Test. The women were also administered the Barratt Impulsiveness Scale (BIS-11). The BN patients displayed significant impairments on all inhibition measures and posited significantly higher impulsivity scores than the controls. Moreover, controlling for impulsivity reduced the group differences in Stroop color naming and excluded letter fluency to nonsignificance, indicating that poor inhibitory control in BN is at least partly attributable to an impulsive disposition.

Deficient activity in the neural systems that mediate self-regulatory control in bulimia nervosa

CONTEXT

Disturbances in neural systems that mediate voluntary self-regulatory processes may contribute to bulimia nervosa (BN) by releasing feeding behaviors from regulatory control.

OBJECTIVE

To study the functional activity in neural circuits that subserve self-regulatory control in women with BN.

DESIGN

We compared functional magnetic resonance imaging blood oxygenation level-dependent responses in patients with BN with healthy controls during performance of the Simon Spatial Incompatibility task.

SETTING

University research institute.

PARTICIPANTS

Forty women: 20 patients with BN and 20 healthy control participants. Main Outcome Measure We used general linear modeling of Simon Spatial Incompatibility task-related activations to compare groups on their patterns of brain activation associated with the successful or unsuccessful engagement of self-regulatory control.

RESULTS

Patients with BN responded more impulsively and made more errors on the task than did healthy controls; patients with the most severe symptoms made the most errors. During correct responding on incongruent trials, patients failed to activate frontostriatal circuits to the same degree as healthy controls in the left inferolateral prefrontal cortex (Brodmann area [BA] 45), bilateral inferior frontal gyrus (BA 44), lenticular and caudate nuclei, and anterior cingulate cortex (BA 24/32). Patients activated the dorsal anterior cingulate cortex (BA 32) more when making errors than when responding correctly. In contrast, healthy participants activated the anterior cingulate cortex more during correct than incorrect responses, and they activated the striatum more when responding incorrectly, likely reflecting an automatic response tendency that, in the absence of concomitant anterior cingulate cortex activity, produced incorrect responses.

CONCLUSIONS

Self-regulatory processes are impaired in women with BN, likely because of their failure to engage frontostriatal circuits appropriately. These findings enhance our understanding of the pathogenesis of BN by pointing to functional abnormalities within a neural system that subserves self-regulatory control, which may contribute to binge eating and other impulsive behaviors in women with BN.

Central coherence in eating disorders: a systematic review

BACKGROUND

This review systematically appraised the research evidence for local versus global information processing to test the hypothesis that people with eating disorders (ED) had weak central coherence.

METHOD

Searches on Medline, EMBASE, PsycINFO and ISI Web of Science databases were conducted in November 2006 and subsequently updated in September 2007. Each search was conducted in two steps: (1) neuropsychological tasks measuring central coherence and (2) words related to cognitive functioning in eating disorders. Data were summarized in a meta-analysis if the number of studies for a given test was >5.

RESULTS

Data were extracted from 16 studies. Meta-analyses were conducted for four tasks obtaining moderate effect sizes. The majority of studies found global processing difficulties across the ED spectrum. The results are less clear regarding local processing.

CONCLUSIONS

People with ED have difficulties in global processing. It is less certain as to whether they have superior local processing. Currently, there is insufficient evidence to refute the weak central coherence hypothesis.

Information processing bias in anorexia nervosa

The aim of this study was to investigate preferential information processing style in Eating Disorders (ED). We compared the performance of participants with EDs against healthy controls in a task that measures cognitive style (reflection-impulsivity) and cognitive efficiency (inefficient-efficient). Sixty non-medicated female participants (healthy controls n=26, anorexia nervosa n=20, bulimia nervosa n=14) took part in the Matching Familiar Figures Test (MFFT), a difficult visual search paradigm with high response uncertainty. Participants with anorexia scored significantly higher on the efficiency dimension score than the control group. No significant differences were found across groups on the dimension 'reflection-impulsivity'. Participants with anorexia are more efficient (quicker response latencies in conjunction with fewer errors) in this visual search task that requires an analytic approach. This supports the hypothesis that individuals with anorexia have a positive bias toward local detail processing, indicative of weak central coherence.

Central coherence in women with bulimia nervosa

OBJECTIVE

To examine the concept of central coherence in women with bulimia nervosa (BN) and address similarities and difference with those with anorexia nervosa (AN) METHOD: Forty two women with BN and 42 matched healthy women, completed neuropsychological testing measuring aspects of central coherence: Rey-Osterrieth Complex Figure (RCFT), Embedded Figures Test (EFT), Block Design Test (BD), Homograph Reading Test (HRT), and Sentence Completion Task (SCT).

RESULTS

The BN group showed superiority in local processing as measured by EFT and lesser relative advantage from segmentation in BD, and difficulties in global processing in both visual and verbal domains as examined by RCFT, HRT, and SCT. Anxiety levels were associated with low central coherence indices in RCFT.

CONCLUSION

People with BN displayed a profile consistent with the weak central coherence hypothesis. Their pattern of cognitive performance resembles that seen in AN although some differences are apparent.

Phenotypes, endophenotypes, and genotypes in bulimia spectrum eating disorders

OBJECTIVES

To review the main phenomenological variants observed among bulimia spectrum syndromes and the factors believed to act etiologically for them and also to generate an etiologic model that accommodates known heterogeneities within the population suffering bulimic syndromes.

METHOD

Defining bulimic syndromes broadly, we address threshold and subthreshold forms of bulimia nervosa (BN) and also the provisional or newly proposed diagnoses of binge eating disorder (BED) and purging disorder (PD). We review evidence bearing on the validity of these diagnostic entities and on the place of sociocultural, family-developmental, neurobiological, and genetic factors in a multidimensional etiologic model for these classifications.

RESULTS

Available data validate certain bulimic phenotypes and subphenotypes that are characterized by such traits as impulsivity or affective instability. Findings associate subphenotypic, or trait-based, variations with putative endophenotypes, such as reduced serotonin transporter activity, and with candidate genotypes affecting the serotonin system; the data also indicate intriguing correspondences between gene environment interactions and subphenotypic variations along such dimensions as novelty seeking.

CONCLUSIONS

Bulimic syndromes sometimes reflect a primary disruption of controls over mood, impulses, and appetite in individuals showing marked psychopathology; at other times, they reflect a more circumscribed erosion of appetitive controls in relatively intact individuals, following prolonged dieting. We argue that dimensional perspectives involving careful attention to comorbid personality traits and symptoms are needed to accommodate existing heterogeneities within the population suffering from bulimia and to characterize the etiologic roles of familial-developmental, neurobiological, and genetic variables (and of interactions among these variables) in bulimic syndromes.

Action monitoring and perfectionism in anorexia nervosa

To study action monitoring in anorexia nervosa, behavioral and EEG measures were obtained in underweight anorexia nervosa patients (n=17) and matched healthy controls (n=19) while performing a speeded choice-reaction task. Our main measures of interest were questionnaire outcomes, reaction times, error rates, and the error-related negativity ERP component. Questionnaire and behavioral results indicated increased perfectionism in patients with anorexia nervosa. In line with their perfectionism and controlled response style patients made significantly less errors than controls. However, when controlling for this difference in error rates, the EEG results demonstrated a reduced error-related negativity in the patient group. These seemingly contradictory outcomes of improved performance and reduced error monitoring are discussed in relation with indications of anterior cingulate cortex hypoactivity in anorexia nervosa patients.

Psychomotor performance and sequence planning in anorexia nervosa before and after weight restoration

BACKGROUND

In the study of psychomotor performance in anorexia nervosa (AN), motor control has not been studied extensively. The present study explores sequence planning in a sample of AN patients.

METHOD

A group of 26 female restricting AN inpatients, aged 14 to 25, was compared with 24 healthy women matched for age and educational level. During the performance of a simple copying task, in which movement planning, but not working capacity, was challenged, the ease with which generally favored graphic production rules could be applied was manipulated. Computerized recordings of the drawing movements allowed detailed analyses of reaction and movement times and of drawing sequences. Fifteen patients were retested after weight restoration, as were 15 controls.

RESULTS

Copying patterns that normally elicit a conflict between preferred graphic production rules induced significantly less slowing in the reaction times of the anorexia nervosa patients than in the controls, both before and after weight restoration. There were no group differences as regards the consistency with which the implicit production rules were applied.

DISCUSSION

AN patients seem to show a fast response style combined with good sequence planning capacity.

Neuropsychological function in bulimia with comorbid borderline personality disorder and depression

BACKGROUND

In bulimia nervosa (BN), borderline personality disorder (BPD) and major depression (MDD) are frequently comorbid conditions. Executive function has been found to be impaired in BPD and MDD, but the impact of comorbidity on neuropsychological function has rarely been investigated.

OBJECTIVE

To investigate neuropsychological function in BN with a focus on comorbid BPD and MDD.

METHODS

One hundred forty-four medication-free female patients entering a study of psychological treatments for BN performed a brief battery of neuropsychological tests. Comorbid MDD and BPD were systematically identified using standard interviews. Neuropsychological test results were compared.

RESULTS

Forty-one subjects had comorbid BPD and 35 had comorbid MDD, while 15 had both. There was no effect of comorbid MDD, but there was a significant effect of BPD and a significant interaction between the diagnosis of MDD and BPD on executive tasks (trail making and Stroop). Thus, compared with subjects without BPD, subjects with BPD performed significantly worse on tests of executive function, while the group with both comorbidities performed even worse.

CONCLUSIONS

There appears to be an additive effect of BPD and MDD resulting in impaired executive neuropsychological function. Future studies on either disorder and on BN should examine and account for the effect of comorbidity.

Neuropsychologische Beeinträchtigungen und kognitive Verarbeitung von Essensreizen bei Anorexia nervosa

Zusammenfassung. Essstörungen stellen eine wichtige psychiatrische Behandlungsindikation dar. Es ist bekannt, dass bei diesen Erkrankungen auch klinisch relevante kognitive Defizite und Auffälligkeiten in der Informationsverarbeitung bestehen, die im Alltag der PatientInnen zu Beeinträchtigungen führen. Insbesondere im Hinblick auf die schwierige und langwierige Behandlung und hohen Rückfallquoten dieser Patientengruppe ist die Berücksichtigung dieser kognitiven Besonderheiten in der Therapie von Essstörungen wichtig. Der vorliegende Artikel beschreibt neurokognitive Auffälligkeiten bei Anorexia nervosa (AN) in verschiedenen relevanten Funktionsbereichen. Im zweiten Teil der Arbeit werden aktuelle Verhaltens- und Bildgebungsstudien zur Verarbeitung von nahrungsrelevanten Stimuli dargestellt.

The relationship between two-dimensional self-esteem and problem solving style in an anorexic inpatient sample

OBJECTIVE

Research examining cognitive and behavioural determinants of anorexia is currently lacking. This has implications for the success of treatment programmes for anorexics, particularly, given the high reported dropout rates. This study examines two-dimensional self-esteem (comprising of self-competence and self-liking) and social problem-solving in an anorexic population and predicts that self-esteem will mediate the relationship between problem-solving and eating pathology by facilitating/inhibiting use of faulty/effective strategies.

METHOD

Twenty-seven anorexic inpatients and 62 controls completed measures of social problem solving and two-dimensional self-esteem.

RESULTS

Anorexics scored significantly higher than the non-clinical group on measures of eating pathology, negative problem orientation, impulsivity/carelessness and avoidance and significantly lower on positive problem orientation and both self-esteem components. In the clinical sample, disordered eating correlated significantly with self-competence, negative problem-orientation and avoidance. Associations between disordered eating and problem solving lost significance when self-esteem was controlled in the clinical group only. Self-competence was found to be the main predictor of eating pathology in the clinical sample while self-liking, impulsivity and negative and positive problem orientation were main predictors in the non-clinical sample.

DISCUSSION

Findings support the two-dimensional self-esteem theory with self-competence only being relevant to the anorexic population and support the hypothesis that self-esteem mediates the relationship between disordered eating and problem solving ability in an anorexic sample. Treatment implications include support for programmes emphasising increasing self-appraisal and self-efficacy.

Cognitive flexibility in anorexia nervosa and bulimia nervosa

The aim of this study was to determine if there are differences in cognitive flexibility in anorexia nervosa and bulimia nervosa. Fifty-three patients with an eating disorder (34 with anorexia nervosa and 19 with bulimia nervosa) and 35 healthy controls participated in the study. A battery of neuropsychological tests for cognitive flexibility was used, including Trail Making B, the Brixton Test, Verbal Fluency, the Haptic Illusion Test, a cognitive shifting task (CatBat) and a picture set test. Using exploratory factor analysis, four factors were obtained: 1: Simple Alternation; 2: Mental Flexibility; 3: Perseveration; and 4: Perceptual Shift. Patients with anorexia nervosa had abnormal scores on Factors 1 and 4. Patients with bulimia nervosa showed a different pattern, with significant impairments in Factors 2 and 4. These findings suggest that differential neuropsychological disturbance in the domain of mental flexibility/rigidity may underlie the spectrum of eating disorders.

Neuropsicologia dos transtornos alimentares: revisão sistemática da literatura

ANTECEDENTES: A etiologia dos transtornos alimentares (TA) ainda não se encontra estabelecida. Dentre os diversos fatores envolvidos, a hipótese de uma disfunção do sistema nervoso central tem sido explorada de diversas maneiras. Assim, a avaliação neuropsicológica de pacientes com TA tem por finalidade investigar a ocorrência de déficits cognitivos associados a estas patologias. OBJETIVOS: O objetivo deste artigo é avaliar o estado atual das investigações sobre a avaliação neuropsicológica em pacientes com TA. MÉTODOS: Foi realizada uma pesquisa bibliográfica - utilizando as seguintes bases de dados como estratégias de procura: MedLINE, PsychoINFO, LILACS e Cochrane Data Bank -, procurando artigos relacionados ao tema e publicados até o ano de 2004. RESULTADOS: A anorexia nervosa é o transtorno alimentar que conta com mais estudos neuropsicológicos e, de uma forma geral, os resultados apontam para déficits de atenção, déficits viso-espaciais e de viso-construção. Na bulimia nervosa, as alterações mais encontradas são déficits de atenção seletiva e das funções executivas. O transtorno da compulsão alimentar periódica ainda não conta com estudos neuropsicológicos até o momento. Após um tratamento bem-sucedido do transtorno alimentar, embora haja uma diminuição dos déficits cognitivos, algumas alterações cognitivas parecem persistir. CONCLUSÕES: Os transtornos alimentares parecem estar associados a algum grau de disfunção neuropsicológica, muito embora as funções específicas que se apresentam deficitárias variem entre os estudos encontrados, talvez em decorrência de variações metodológicas. O fato de que, após o tratamento, alguns pacientes apresentem uma melhora no funcionamento cognitivo poderia indicar que, em alguns casos, os déficits seriam funcionais. A ausência de melhora no funcionamento cognitivo de alguns pacientes, após diversas formas de intervenção, pode sugerir que estes déficits antecederiam o desenvolvimento dos transtornos alimentares, podendo, assim, contribuir para seu desenvolvimento ou para um pior prognóstico. O melhor delineamento do perfil cognitivo dos pacientes com transtorno alimentar torna-se importante para orientar abordagens terapêuticas mais seletivas.

Cognitive processing of anorexic patients in recognition tasks: an event-related potentials study

OBJECTIVE

We used event-related potentials (ERPs) to test whether anorexic subjects have difficulties in filtering out irrelevant stimuli in controlled information processing tasks.

METHODS

ERPs from 12 anorexic patients were recorded during recognition of simple and complex body images and simple and complex geometrical shapes.

RESULTS

Anorexic subjects had larger P300 amplitudes for frequent stimuli during body images and simple geometrical shape recognition tasks. Longer P300 latencies were also found in simple geometrical shape recognition tasks, although task complexity had no effect on the P300 latency and amplitude.

DISCUSSION

These results are explained in terms of nonspecific hyperarousal in mental anorexia and relative inability to filter out irrelevant stimuli leading to working memory saturation.

Laxative misuse and behavioral disinhibition in bulimia nervosa

OBJECTIVE

Various reports suggest that purging with laxatives is associated with greater behavioral impulsivity in bulimia nervosa (BN) patients. We investigated the extent to which laxative misuse corresponds to specific impulse-control problems.

METHOD

Participants included bulimic women who misuse laxatives (BNL+; n = 12), bulimic women who do not misuse laxatives (BNL-; n = 33), and healthy normal eaters (NE; n = 26). Participants completed the Go/No-Go discrimination task (a well-validated computerized measure of response disinhibition), as well as self-report questionnaires of impulsivity, eating symptoms, and general psychopathology.

RESULTS

Compared with the other groups, the BNL+ group made more commission errors on the Go/No-Go under cues for punishment, indicating they were more disinhibited when faced with possible negative outcomes. Compared with the BNL- group, the BNL+ group was also more likely to differ from the NE group on self-reported impulsivity. There were no differences between the two bulimic groups on eating symptoms and the three groups did not differ in terms of general psychopathology.

DISCUSSION

Findings suggest that, controlling for eating symptoms and psychopathology, laxative misuse among BN patients is associated with difficulty inhibiting incorrect responses in the face of perceived threats.

Causes of eating disorders

Anorexia nervosa and bulimia nervosa have emerged as the predominant eating disorders. We review the recent research evidence pertaining to the development of these disorders, including sociocultural factors (e.g., media and peer influences), family factors (e.g., enmeshment and criticism), negative affect, low self-esteem, and body dissatisfaction. Also reviewed are cognitive and biological aspects of eating disorders. Some contributory factors appear to be necessary for the appearance of eating disorders, but none is sufficient. Eating disorders may represent a way of coping with problems of identity and personal control.

Perceptual illusions in eating disorders: rigid and fluctuating styles

This study investigated perceptual styles in anorexia nervosa (AN) and bulimia nervosa (BN) using a perceptual set task. We hypothesised that, consistent with personality style research. AN patients might be more rigid in style than those with BN or no eating disorder. We found that once an illusion had been established, participants with AN and BN showed more illusions than non-ED women. However, while AN patients responded rigidly, giving the same response repeatedly, BN patients were more likely to change their responses. The study suggests interesting differences to be followed up in future research. Differences in rigid and fluctuating perceptual styles may have implications for understanding the phenomenology of eating disorders, and have implications for treatment.

[Haptic perception and EEG changes in anorexia nervosa]

OBJECTIVES

We predicted that due to diminished somatosensory integrative ability, the anorectic patients would have problems reproducing haptic stimuli. In addition we sought to determine whether EEGs from anorectic patients (AN) and the healthy controls (CO) would show discrepancies between the two groups during haptic explorations in theta-power over the right parietal region.

METHOD

EEG power (theta-power) data of AN (n = 13) and CO (n = 13) were analyzed during haptic exploration tasks and rest intervals. The haptic explorations consisted of palpating the structure of six sunken reliefs in sequence with both hands, eyes closed. After each exploration the structure was drawn on a piece of paper.

RESULTS

The reproductions of haptic stimuli submitted by the anorectic patients were of notably poorer quality than those of the healthy controls. During rest intervals and haptic explorations, spectral power was generally lower in the AN group in comparison to the healthy controls. Significant theta-power differences between groups showed over the right parietal cortex during haptic explorations. The decrease in EEG power in the anorectic patients in the theta bands across the right parietal region during haptic exploration tasks could be interpreted as a minor activation of visuo-spatial regions. The results of the haptic explorations as well as the EEG-power changes indicate a cortical dysfunction and deficits in somatosensory integration processing in anorexia nervosa patients.

Differential hemispheric involvement in anorexia nervosa

Hemispheric function was assessed in 22 restricting anorexia nervosa (AN) female subjects and 22 normal female controls. Two verbal and two visuospatial tasks and a set of psychopathological tests were administered. The failure of the "classic" lateralization tests to reveal the expected left hemisphere dominance or a right hemisphere deficit in AN group, as compared to controls, is counterbalanced by the tendency of the psychopathological tests to prove the neuropsychological hypothesis of the present study. Neuropsychological interpretation of psychopathological data, however, does not constitute direct evidence and so further studies and more sophisticated techniques are needed.