Evaluation of Enhanced Attention to Local Detail in Anorexia Nervosa Using the Embedded Figures Test; an fMRI Study

Abstract

The behavioural literature in anorexia nervosa and autism spectrum disorders has indicated an overlap in cognitive profiles. One such domain is the enhancement of local processing over global processing. While functional imaging studies of autism spectrum disorder have revealed differential neural patterns compared to controls in response to tests of local versus global processing, no studies have explored such effects in anorexia nervosa. This study uses functional magnetic resonance imaging in conjunction with the embedded figures test, to explore the neural correlates of this enhanced attention to detail in the largest anorexia nervosa cohort to date. On the embedded figures tests participants are required to indicate which of two complex figures contains a simple geometrical shape. The findings indicate that whilst healthy controls showed greater accuracy on the task than people with anorexia nervosa, different brain regions were recruited. Healthy controls showed greater activation in the precuneus whilst people with anorexia nervosa showed greater activation in the fusiform gyrus. This suggests that different cognitive strategies were used to perform the task, i.e. healthy controls demonstrated greater emphasis on visuospatial searching and people with anorexia nervosa employed a more object recognition-based approach. This is in accordance with previous findings in autism spectrum disorder using a similar methodology and has implications for therapies addressing the appropriate adjustment of cognitive strategies in anorexia nervosa.

Cognitive remediation, brain function and central coherence: an anorexia nervosa pilot study

“…As such, the paradigm requires participants to switch their attention between two stimuli to search for the simple shape and utilize a more global strategy to successfully perform the task. Our previous cross-sectional fMRI findings on the EFT reported poorer performance in AN alongside greater task-related activation in the fusiform gyrus and greater task-related deactivation in the posterior cingulate cortex [19]. Their poorer performance was in line with previous literature on central coherence [6,7], and the changes in BOLD response suggested that those with AN do not direct their neural effort as efficiently as controls.…”

“…On the Embedded Figures Tests (described in detail in [19]), the participants were required to indicate which of two figures contained a simple geometrical shape by moving a joystick to the left or to the right. The level of difficulty varied, and the figures were either simple (SEF) or complex (CEF) in composition (see [25] for further details).…”

“…Details of the MRI acquisition and of the image analysis are described in detail in earlier reports from our group [19]. Group × time interaction analyses were performed to assess if there was a difference in improvement over time between the two groups on either the SEF or the CEF.…”

“…Central coherence, as measured by a variant of the embedded figures test (EFT), was chosen as a previous cross-sectional investigation of this paradigm found better performance in healthy controls (HC) with less neural effort, indicative of utilizing a more global approach on this paradigm [19]. Many of the exercises in CRT focus on teaching patients to adopt a more global approach [20,21], but their effects have not been evaluated using fMRI.…”

Disruption of brain white matter microstructure in women with anorexia nervosa

“…44 These abnormalities are thought to rely on alterations of long-range connections between prefrontal and parieto-occipital areas in other disorders, 45 and these same areas also seem to be implicated in weak central coherence in patients with anorexia nervosa. 46 However, the specific role of the SLF in these deficits in patients with anorexia nervosa remains to be further investigated.…”