Distorted Self-image In Body Image Disorder Due To Visual Brain Glitch?
Although they look normal, people suffering from body dysmorphic disorder (BDD) perceive themselves as ugly and disfigured. New imaging research reveals that the brains of people with BDD look normal, but function abnormally when processing visual details. The UCLA findings are the first to demonstrate a biological reason for patients’ distorted body image.
MRI scans of the brains of BDD patients show predominant activity on the left side of the brain. (Credit: Image courtesy of University of California – Los Angeles)
“Our discovery suggests that the BDD brain’s hardware is fine, but there’s a glitch in the operating software that prevents patients from seeing themselves as others do,” explained Dr. Jamie Feusner, principal investigator and assistant professor of psychiatry at UCLA’s Semel Institute. “Now that we’ve identified a possible physical cause, down the road we may be able to pinpoint ways that patients’ brains can be retrained to perceive faces more accurately.”
Individuals with BDD fixate on an imagined flaw in appearance or a slight physical abnormality. To fix their “problem,” they tend to pursue plastic surgery — sometimes repeatedly. They often feel ashamed, depressed and anxious, increasing their risk of suicide.
Affecting an estimated two percent of the population, BDD tends to run in families and is especially common in persons with obsessive-compulsive disorder (OCD). Thirty percent of people with BDD suffer from eating disorders, which are also linked to a distorted self-image.
Feusner was curious whether BDD patients’ brains interfered with the interpretation of visual input, and if so, whether this glitch occurred when looking at faces other than their own.
“We hoped that asking patients to focus on others’ faces would allow them to be less emotionally engaged during the experiment,” he said.
For the first time, functional magnetic resonance imaging (fMRI) was used to reveal how the patients’ brains processed visual input. The UCLA team outfitted 12 BDD patients with special goggles that enabled them to view digital photos of various faces as they underwent a brain scan.
Each volunteer viewed three types of images. The first type was an untouched photo. The second type was a photo altered to eliminate facial details that appear frequently, such as freckles, wrinkles and scars. This “low frequency” technique blurred the final image.
The third type of image essentially subtracted the blurred second image from the untouched photo. This “high frequency” technique resulted in a finely detailed line drawing.
Feusner’s team compared the BDD patients’ responses to 12 control subjects matched by age, gender, education and handedness. What the scientists observed surprised them.
“We saw a clear difference in how the right and left sides of the brain worked in people with BDD versus those without the disorder,” noted Feusner.
The limited number of BDD patients in this study more often used their brain’s left side — the analytic side attuned to complex detail — even when processing the less intricate, low-frequency images. In contrast, the left sides of the control subjects’ brains activated only to interpret the more detailed high-frequency information. Their brains processed the untouched and low-frequency images on the right side, which is geared toward seeing things in their entirety.
“We don’t know why BDD patients analyze all faces as if they are high frequency,” said Feusner. “The findings suggest that BDD brains are programmed to extract details — or fill them in where they don’t exist. It’s possible they are thinking of their own face even when they are looking at others.”
Feusner also recently discovered that the more severe the BDD patient’s symptoms, the more strongly the brain’s left side activates during visual processing. He is currently studying how BDD patients process their own faces in order to explore how emotional arousal may influence visual processing.
“All of these findings indicate that BDD has a biological link and can no longer be attributed solely to our society’s focus on appearance,” he concluded… as much as can be derrived from anecdotical evidence provided by a typical fMRI study, one should add cautiously.
Arch Gen Psychiatry. 2007 Dec;64(12):1417-25.
Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at the University of California, Los Angeles, 300 UCLA Medical Plaza, Ste 2345, Los Angeles, CA 90024, USA. email@example.com
CONTEXT: Body dysmorphic disorder (BDD) is a severe psychiatric condition in which individuals are preoccupied with perceived appearance defects. Clinical observation suggests that patients with BDD focus on details of their appearance at the expense of configural elements. This study examines abnormalities in visual information processing in BDD that may underlie clinical symptoms. OBJECTIVE: To determine whether patients with BDD have abnormal patterns of brain activation when visually processing others’ faces with high, low, or normal spatial frequency information. DESIGN: Case-control study. SETTING: University hospital. PARTICIPANTS: Twelve right-handed, medication-free subjects with BDD and 13 control subjects matched by age, sex, and educational achievement. Intervention Functional magnetic resonance imaging while performing matching tasks of face stimuli. Stimuli were neutral-expression photographs of others’ faces that were unaltered, altered to include only high spatial frequency visual information, or altered to include only low spatial frequency visual information. MAIN OUTCOME MEASURE: Blood oxygen level-dependent functional magnetic resonance imaging signal changes in the BDD and control groups during tasks with each stimulus type. RESULTS: Subjects with BDD showed greater left hemisphere activity relative to controls, particularly in lateral prefrontal cortex and lateral temporal lobe regions for all face tasks (and dorsal anterior cingulate activity for the low spatial frequency task). Controls recruited left-sided prefrontal and dorsal anterior cingulate activity only for the high spatial frequency task. CONCLUSIONS: Subjects with BDD demonstrate fundamental differences from controls in visually processing others’ faces. The predominance of left-sided activity for low spatial frequency and normal faces suggests detail encoding and analysis rather than holistic processing, a pattern evident in controls only for high spatial frequency faces. These abnormalities may be associated with apparent perceptual distortions in patients with BDD. The fact that these findings occurred while subjects viewed others’ faces suggests differences in visual processing beyond distortions of their own appearance.