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Dissertation
Behavioral dissociation of orbital-medial and dorsolateral frontal lobe functioning in patients with intermittent explosive disorder
Doctor of Philosophy (Ph.D.), Medical College of Pennsylvania and Hahnemann University
Mar 2000
DOI:
https://doi.org/10.17918/00009920
Abstract
Aggression can be defined as an intense, harmful, and hostile action taken against oneself, another person, or an object. Aggression can be expressed verbally, indirectly or directly to another person. The DSM-IV has only one disorder with aggressive behavior as a primary symptom, Intermittent Explosive Disorder (IED). Criteria for IED include several episodes of impulsive aggressive behavior out of proportion to provocation. To date no study has examined the neuropsychological profile of subjects with IED. Humans and animals with lesions to the orbital/medial prefrontal cortex and associated limbic brain areas display impulsive aggressive behavior. Associated cognitive and perceptual deficits include emotional misperception, disinhibition, and impaired smell identification. The goal of the present study was to test the hypothesis that subjects with IED would have a cognitive profile similar to patients with lesions to orbital/medial prefrontal cortex. Subjects with IED (N = 24) and age-, education-, and IQ-matched control subjects (N = 22) were given tests of facial expression identification, response inhibition, and smell identification. These tests have been linked to the integrity of the orbital/medial prefrontal cortex. To determine specificity of prefrontal dysfunction, subjects were given control tests of working memory linked to the dorsolateral prefrontal cortex. Subjects with IED performed significantly worse than controls on the three orbital/medial tasks. Subjects with IED were impaired at identifying negative facial expressions and showed a bias to label neutral faces with a negative expression. IED subjects had difficulty learning associations and correctly altering their behavior in response to punishment in a simulated gambling task. They were also impaired at identifying odors. Subjects with IED performed similar to controls on the dorsolateral control tasks of working memory. Subjects with IED showed a pattern of impairments that resembled impairments in patients with orbital/medial prefrontal cortex lesions. However, the degree of impairments in IED was milder than patients with lesions. This study provides evidence for a mild dysfunction in orbital/medial prefrontal cortex in IED. This study has implications for psychotherapeutic interventions in IED. Future studies could more directly test the orbital/medial hypothesis in IED by functional neuroimaging of prefrontal cortex while subjects perform tests investigated in this study.
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Details
- Title
- Behavioral dissociation of orbital-medial and dorsolateral frontal lobe functioning in patients with intermittent explosive disorder
- Creators
- Mary Helen Best
- Contributors
- J. Michael Williams (Advisor) - Drexel University, Medical College of Pennsylvania and Hahnemann University (1993-1996, 1998-2002)
- Awarding Institution
- Medical College of Pennsylvania and Hahnemann University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Medical College of Pennsylvania and Hahnemann University; Philadelphia, Pennsylvania
- Number of pages
- viii, 96 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Medical College of Pennsylvania and Hahnemann University (1993-1996, 1998-2002); Clinical and Health Psychology [Historical]; School of Health Professions (1998-2000)
- Other Identifier
- 991021889013504721