Perceptual Abnormalities and Their Malleability in BDD

Официальное название

Neural Mechanisms of Perceptual Abnormalities and Their Malleability in Body Dysmorphic Disorder

Обзор

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.

Подробное описание

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.

Вмешательства

• Поведенческое attentional modulation
  Attentional instructions when viewing faces will be given
• Другое perceptual modulation
  Faces will be presented of varying durations
• Другое naturalistic viewing
  Faces will be viewed without specific instructions

Первичные конечные точки

• Face inversion effect [Срок оценки: Baseline]
• Brain connectivity and activation in the dorsal and ventral visual stream [Срок оценки: Baseline]
• Eye gaze behavior [Срок оценки: Baseline]
• Emotional valence [Срок оценки: Baseline]
• Change in face inversion effect [Срок оценки: Within a week after baseline]
• Change in brain connectivity and activation in the dorsal and ventral visual stream [Срок оценки: Within a week after baseline]
• Change in eye gaze behavior [Срок оценки: Within a week after baseline]
• Change in emotional valence [Срок оценки: Within a week after baseline]

Вторичные конечные точки (6)

• The body dysmorphic version of the Yale-Brown Obsessive-Compulsive Scale 0-48 values higher score= worse outcome [Срок оценки: Baseline]
• The Brown Assessment of Beliefs Scale 0-24 values higher score= worse outcome [Срок оценки: Baseline]
• Body Image States Scale 1-9 values higher the score= better outcome [Срок оценки: Baseline]
• Change in the body dysmorphic version of the Yale-Brown Obsessive- Compulsive Scale 0-48 values higher score= worse outcome [Срок оценки: 7-10 days after baseline]
• Change in the Brown Assessment of Beliefs Scale 0-24 values higher score= worse outcome [Срок оценки: 7-10 days after baseline]
• Change in the Body Image States Scale 1-9 values higher the score= better outcome [Срок оценки: 7-10 days after baseline]

Критерии участия

Критерии включения

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

Критерии включения

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

Критерии включения

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

Критерии исключения

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

Exclusion:

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

Критерии исключения

Healthy Controls: Exclusion

• Any current Axis I disorder
• lifetime: bipolar disorder or psychotic disorder
• Psychiatric medication

Критерии исключения

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).

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Да

Дизайн исследования

Распределение

Рандомизированное

Модель

Параллельные группы

Маскирование

Простое слепое

Основная цель

Фундаментальное исследование

Центры проведения

Канада · 1 центр

• Centre for Addiction and Mental Health — Toronto

Идентификаторы

NCT: NCT04373629 · R01MH121520-01A1 · R01MH121520

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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