Neural Mechanisms of Perceptual Abnormalities and Their Malleability in Body Dysmorphic Disorder
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 146
- 试验地点
- 2
- 主要终点
- Emotional valence
研究概览
简要总结
A core symptom of body dysmorphic disorder (BDD) is perceptual distortions for appearance, which contributes to poor insight and delusionality, limits engagement in treatment, and puts individuals at risk for relapse. Results from this study will provide a comprehensive mechanistic model of brain, behavioral, and emotional contributors to abnormal perceptual processing, as well as how malleable it is with visual modulation techniques. This will lay the groundwork for next-step translational perceptual retraining approaches.
详细描述
Individuals with body dysmorphic disorder (BDD) misperceive specific aspects of one's own appearance to be conspicuously flawed or defective, despite these being unnoticeable or appearing minuscule to others. With convictions of disfigurement and ugliness, individuals with BDD typically have poor insight or delusional beliefs, obsessive thoughts and compulsive behaviors, anxiety, and depression. These result in significant difficulties in functioning, depression, suicide attempts (25%), and psychiatric hospitalization (50%). Despite this, relatively few studies of the neurobiology, and few treatment studies, have been conducted. This underscores a critical need for research to identify novel targets for intervention based on a comprehensive understanding of the pathophysiological mechanisms. Neuropsychological, behavioral, and neurobiological research by investigators have uncovered mechanisms that may contribute to perceptual distortions, including prominent abnormalities in visual processing systems. These have contributed to a model of diminished global/holistic processing and enhanced local/detailed processing, attributed to "bottom-up" and "top-down" disturbances in perception. Using psychophysical experiments and novel visual modulation techniques, investigators have probed the brain's visual systems responsible for global and local processing and found early evidence that they may be modifiable in BDD. These techniques include a "top-down" attentional modulation and a "bottom-up" perceptual modulation strategy. Abnormal eye gaze and emotional arousal when viewing faces may further contribute to abnormal perception. Whether these brain and behavior abnormalities are directly linked to abnormal perception remains to be understood. Accordingly, this study will determine a) if abnormalities in neural activation and connectivity in BDD when viewing one's own appearance are directly associated with abnormalities in perceptual functioning; and b) if changes in neural activation and connectivity from these visual modulation strategies are linked to changes in perceptual functioning, thus representing potential biomarkers. Investigators will also determine how attentional systems, eye gaze behaviors and emotional arousal interact with brain functioning in visual systems, and with global and local perceptual functioning. Investigators will enroll participants with BDD, with subclinical BDD, and healthy controls who will undergo functional magnetic resonance imaging while viewing photographs of own, and others' faces. Investigators will obtain measures of global and local visual processing, emotional arousal while participants view own face, and eye gaze behaviors using eye tracking. To understand the malleability of global/local perception, and the neural mechanisms of these changes, investigators will determine whether repeated visual modulation using top-down and bottom-up strategies results in alterations of perceptual functioning and brain activity/connectivity, and relationships between them. Results will provide a comprehensive mechanistic model of abnormal visual information processing underlying the core symptom domain of misperceptions of appearance. This will lay the groundwork for next-step translational approaches.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- Single (Outcomes Assessor)
入排标准
- 年龄范围
- 18 Years 至 40 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Body dysmorphic disorder: Inclusion:
- •males or females
- •ages 18-40
- •meet Diagnostic and Statistical Manual-5 (DSM-5) criteria for Body Dysmorphic Disorder
- •have a Body Dysmorphic Disorder version of the Yale-Brown Obsessive-Compulsive Disorder Scale (BDD-YBOCS) score of ≥20
- •primary appearance concerns of the face or head area
- •medication naïve or medication free for at least 8 weeks prior to enrollment
- •Inclusion Criteria:
- •Subclinical body dysmorphic disorder: Inclusion:
- •males or females
- •ages 18-40
- •have a score on the Dysmorphic Concern Questionnaire of ≥8 [1 standard deviation (STD) above population norms] - primary appearance concerns of the face or head area
- •medication naïve or medication free for at least 8 weeks prior to enrollment
- •Inclusion Criteria:
- •Healthy controls: Inclusion
- •Healthy males and females from any racial or ethnic background - ages 18-40
- •have a score on the Dysmorphic Concern Questionnaire of <8
排除标准
- •Body dysmorphic disorder: Exclusion
- •concurrent major Axis I disorders including substance use disorders, aside from anxiety disorders or depressive disorders, as these comorbidities are very common and the sample would otherwise be non-representative; however BDD must be the primary diagnosis.
- •lifetime: bipolar disorder or psychotic disorder.
- •psychotropic medications, aside from a short half-life sedative/hypnotic for insomnia, or a short half-life benzodiazepine as needed for anxiety but not exceeding a frequency of 3 doses in one week and not to be taken on the days of the training or MRI scan
- •current cognitive-behavioral therapy
- •Subclinical body dysmorphic disorder: Exclusion
- •meet full DSM-5 criteria for Body Dysmorphic Disorder
- •current Axis I disorders including substance use disorders
- •lifetime: bipolar disorder or psychotic disorder
- •psychotropic medications, aside from a short half-life sedative/hypnotic for insomnia, or a short half-life benzodiazepine as needed for anxiety but not exceeding a frequency of 3 doses in one week and not to be taken on the days of the training or MRI scan
- •current cognitive-behavioral therapy
- •Exclusion Criteria:
- •Healthy Controls: Exclusion
- •Any current Axis I disorder
- •lifetime: bipolar disorder or psychotic disorder
- •Psychiatric medication
- •Exclusion Criteria:
- •All participants: Exclusion
- •Neurological disorder
- •Pregnancy
- •Current major medical disorders that may affect cerebral metabolism such as diabetes or thyroid disorders - Current risk of suicide with a plan and intent
- •Ferromagnetic metal implantations or devices (electronic implants or devices, infusion pumps, aneurysm clips, metal fragments or foreign bodies, metal prostheses, joints, rods or plates)
- •Visual acuity worse than 20/35 for each eye as determined by Snellen close vision acuity chart (vision will be tested with corrective lenses if participant uses them).
结局指标
主要结局
Emotional valence
时间窗: Baseline
Investigators will use automated facial emotional recognition software to calculate valence based on the activity of specific facial landmarks automatically read from video capture of participants while viewing one's own face. The data will be collected simultaneously with the eye-tracking data collection while viewing own faces. The dependent variable of emotional is calculated as the mean, across the entire face viewing, of the intensity of positive emotional expressions minus the intensity of the negative expression with the highest intensity.
Change in face inversion effect
时间窗: Within a week after baseline
In a force-choice recognition task, participants will view sets of upright target faces
Change in brain connectivity and activation in the dorsal and ventral visual stream
时间窗: Within a week after baseline
Investigators will obtain functional magnetic resonance imaging (fMRI) data while participants view photographs of one's own face. After preprocessing and analysis investigators will be able to determine: a) baseline associations between brain activity and connectivity and global/ local processing (face inversion effect), and b) associations between changes in brain activity and connectivity with changes in global/local processing (face inversion effect)
Face inversion effect
时间窗: Baseline
In a force-choice recognition task, participants will view sets of upright target faces followed by 2 upright selection faces, and sets of inverted target faces followed by 2 inverted selection faces. Participants will be instructed to select one of the two faces that is the same as the target face, as quickly and as accurately as possible. The dependent variable is the difference in response times for upright vs. inverted faces.
Brain connectivity and activation in the dorsal and ventral visual stream
时间窗: Baseline
Investigators will obtain functional magnetic resonance imaging (fMRI) data while participants view photographs of one's face. After preprocessing and analysis investigators will be able to determine: a) baseline associations between brain activity and connectivity and global/ local processing (face inversion effect), and b) associations between changes in brain activity and connectivity with changes in global/local processing (face inversion effect)
Eye gaze behavior
时间窗: Baseline
Investigators will use eye-tracking for behavioral assessments related to viewing photos of one's face. The primary dependent variable will be mean fixation duration, defined as the mean time that eye gaze is limited to one area (using k-means clustering) across the total viewing duration. We will use an eye-tracker camera to collect data while individuals view photos of one's face. Each face will be 3.5 sec.
Change in eye gaze behavior
时间窗: Within a week after baseline
Investigators will use eye-tracking for behavioral assessments related to viewing photos of one's face. The primary dependent variable will be mean fixation duration, defined as the mean time that eye gaze is limited to one area (using k-means clustering) across the total viewing duration. Investigators will use an eye-tracker camera to collect data while individuals view photos of one's own face. Each face will be 3.5 sec.
Change in emotional valence
时间窗: Within a week after baseline
Investigators will use automated facial emotional recognition software to calculate valence based on the activity of specific facial landmarks automatically read from video capture of participants while viewing one's own face. The data will be collected simultaneously with the eye-tracking data collection while viewing own faces. The dependent variable of emotional is calculated as the mean, across the entire face viewing, of the intensity of positive emotional expressions minus the intensity of the negative expression with the highest intensity.
次要结局
- Change in the Body Image States Scale 1-9 values higher the score= better outcome(7-10 days after baseline)
- The body dysmorphic version of the Yale-Brown Obsessive-Compulsive Scale 0-48 values higher score= worse outcome(Baseline)
- Change in the Brown Assessment of Beliefs Scale 0-24 values higher score= worse outcome(7-10 days after baseline)
- Change in the body dysmorphic version of the Yale-Brown Obsessive- Compulsive Scale 0-48 values higher score= worse outcome(7-10 days after baseline)
- The Brown Assessment of Beliefs Scale 0-24 values higher score= worse outcome(Baseline)
- Body Image States Scale 1-9 values higher the score= better outcome(Baseline)
研究者
Jamie D. Feusner
Professor of Psychiatry
Centre for Addiction and Mental Health