Abnormalities of visual processing and frontostriatal systems in body dysmorphic disorder

Abstract

Context: Body dysmorphic disorder (BDD) is a psychiatric disorder in which individuals are preoccupied with perceived defects in their appearance, often related to their face. Little is known about its pathophysiology, although early research provides evidence of abnormal visual processing.

Objective: To determine whether patients with BDD have abnormal patterns of brain activation when visually processing their own face with high, low, or normal spatial resolution.

Design: Case-control study.

Setting: A university hospital.

Participants: Seventeen right-handed medication-free subjects with BDD and 16 matched healthy control subjects. Intervention Functional magnetic resonance imaging while viewing photographs of face stimuli. Stimuli were neutral-expression photographs of the patient's own face and a familiar face (control stimuli) that were unaltered, altered to include only high spatial frequency (fine spatial resolution), or altered to include only low spatial frequency (low spatial resolution).

Main outcome measure: Blood oxygen level-dependent signal changes in the BDD and control groups during each stimulus type.

Results: Subjects with BDD showed relative hyperactivity in the left orbitofrontal cortex and bilateral head of the caudate for the unaltered own-face vs familiar-face condition. They showed relative hypoactivity in the left occipital cortex for the low spatial frequency faces. Differences in activity in frontostriatal systems but not visual cortex covaried with aversiveness ratings of the faces. Severity of BDD symptoms correlated with activity in frontostriatal systems and visual cortex.

Conclusions: These results suggest abnormalities in visual processing and frontostriatal systems in BDD. Hypoactivation in the occipital cortex for low spatial frequency faces may indicate either primary visual system abnormalities for configural face elements or top-down modulation of visual processing. Frontostriatal hyperactivity may be associated both with aversion and with symptoms of obsessive thoughts and compulsive behaviors.

Figure 1

Example of own-face stimuli. HSF indicates high spatial frequency; LSF, low spatial frequency; and NSF, normal spatial frequency.

Figure 2

Mean aversiveness ratings of own-face stimuli on a Likert scale of 0 to 10. There was a significant group effect (F_1,31=29.24; P < .001) but a nonsignificant stimulus type effect (F_2,62=0.15; P =.86) and a nonsignificant group × stimulus interaction effect (F_2,62=2.41; P =.10). Error bars indicate standard errors of the mean; BDD, body dysmorphic disorder; NSF, normal spatial frequency; HSF, high spatial frequency; and LSF, low spatial frequency.

Figure 3

Significant differences in regional brain activity between groups. A, Regional brain activity is greater for subjects with body dysmorphic disorder than for control subjects for normal spatial frequency own-face vs familiar-face contrast in the caudate and left orbitofrontal cortex. B, Regional brain activity is greater for control subjects than for subjects with body dysmorphic disorder for low spatial frequency own-face vs oval contrast in the left visual cortex. L indicates left; R, right.

Figure 4

Signal change percentages for normal spatial frequency (A) and low spatial frequency (B) own-face and familiar-face stimuli in brain regions found to be different between groups, each contrasted to the low-level baseline (oval). P values indicate significant differences between groups, which were evident for own-face vs familiar-face contrasts (A) and own-face vs oval contrasts (B). *P<.005; †P<.05. A, Effect sizes for significant normal spatial frequency own-face vs familiar-face contrasts are as follows: right caudate, 0.40; left caudate, 0.11; and left orbitofrontal cortex (OFC), 0.16. B, Effect sizes for significant low spatial frequency own-face vs oval contrasts are as follows: left lingual gyrus, −1.37; left occipital pole, −1.45; and left occipital fusiform gyrus, −1.37. Error bars indicate standard errors of the mean; BDD, body dysmorphic disorder.

Figure 5

Regions positively correlated with body dysmorphic disorder symptom severity as measured by the body dysmorphic disorder version of the Yale-Brown Obsessive Compulsive Scale. Representative slices depict activations in the right visual cortex (A), right caudate (B), right precentral and postcentral gyri (C), right anterior cingulate gyrus (D), and right orbitofrontal cortex (E). R indicates right; L, left; P, posterior; and A, anterior.

Figure 6

Scatter plots representing signal change percentage as a function of scores on the body dysmorphic disorder version of the Yale-Brown Obsessive Compulsive Scale (BDD-YBOCS) in regions found to be positively correlated with symptom severity (normal spatial frequency own-face vs familiar-face contrast). OFC indicates orbitofrontal cortex.