Magnetic resonance imaging study of the orbitofrontal cortex in autism.
ABSTRACT The orbitofrontal cortex is involved in multiple psychologic functions, such as emotional and cognitive processing, learning, and social behavior. These functions are variably impaired in individuals with autism. The present study examined the size of the orbitofrontal cortex, and its medial and lateral subdivisions, using magnetic resonance imaging (MRI) scans obtained from 40 non-mentally retarded individuals with autism and 41 healthy controls. No differences were observed between the two groups on any of the orbitofrontal cortex measurements. However, when compared with controls, a smaller right lateral orbitofrontal cortex was observed in children and adolescents with autism, whereas a larger right lateral orbitofrontal cortex was found in adult patients. Interestingly, a positive relationship was found in the patient group between circumscribed interests and all orbitofrontal cortex structures. The present study suggests the absence of global volumetric abnormalities in the orbitofrontal cortex in autism and indicates that the functional disturbances in this structure might not be related to anatomic alterations.
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Article: Corticobasal degeneration.[show abstract] [hide abstract]
ABSTRACT: Opinion statement Corticobasal degeneration (CBD) is a neurodegenerative disorder characterized clinically by a combination of cortical and basal ganglia signs. Pathologically, it is classified as a tauopathy. The most distinctive clinical feature is its unilateral or markedly asymmetric presentation; among parkinsonian syndromes, with rare exceptions, only Parkinson’s disease presents with such asymmetry. The most common presenting cortical features include apraxia (patients often complain of a “useless” limb), aphasia (usually nonfluent), parietal lobe sensory signs (agraphesthesia, extinction, astereognosis), frontal dementia, or myoclonus. Basal ganglia signs include rigidity, akinesia, limb dystonia, and postural instability. The diagnosis is often challenging for three reasons: 1) The full complement of findings are rarely seen at presentation; 2) If CBD is not suspected, subtle but relevant findings (eg, extinction, language impairment, myoclonus, or apraxia) may not be searched for or appreciated; 3) The clinical picture of CBD has substantial overlap with a variety of other parkinsonian and dementing illnesses. The differential diagnosis includes Parkinson’s disease, progressive supranuclear palsy, frontotemporal dementia, primary progressive aphasia, and Alzheimer’s disease. The clinical diagnosis is not confirmed pathologically in up to half of cases, so the term corticobasal syndrome is often preferred during life, reserving the term corticobasal degeneration for pathologically verified cases. Treatment of CBD is primarily supportive, and most patients die within 10 years of onset. Parkinsonian signs may improve to a modest degree with levodopa, clonaze pam can suppress myoclonus, and botulinum toxin can relieve dystonia. Early speech therapy, physical therapy, and occupational therapy, as well as assist devices such as a rolling walker may improve functioning and reduce complications such as aspiration pneumonia and falls. With time, however, most patients lose their independence and mobility. Throughout the course of the illness (particularly when it is advanced), caring for the caregiver is as important as caring for the patient.Journal of Neurology Neurosurgery & Psychiatry 04/2000; 68(3):275. · 4.92 Impact Factor
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ABSTRACT: The Autism Diagnostic Observation Schedule (ADOS), a standardized protocol for observation of social and communicative behavior associated with autism, is described. The instrument consists of a series of structured and semistructured presses for interaction, accompanied by coding of specific target behaviors associated with particular tasks and by general ratings of the quality of behaviors. Interrater reliability for five raters exceeded weighted kappas of .55 for each item and each pair of raters for matched samples of 15 to 40 autistic and nonautistic, mildly mentally handicapped children (M IQ = 59) between the ages of 6 and 18 years. Test-retest reliability was adequate. Further analyses compared these groups to two additional samples of autistic and nonautistic subjects with normal intelligence (M IQ = 95), matched for sex and chronological age. Analyses yielded clear diagnostic differences in general ratings of social behavior, specific aspects of communication, and restricted or stereotypic behaviors and interests. Clinical guidelines for the diagnosis of autism in the draft version of ICD-10 were operationalized in terms of abnormalities on specific ADOS items. An algorithm based on these items was shown to have high reliability and discriminant validity.Journal of Autism and Developmental Disorders 07/1989; 19(2):185-212. · 3.34 Impact Factor
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ABSTRACT: The mind's ability to think about the mind has attracted substantial research interest in cognitive science in recent decades, as 'theory of mind'. No research has attempted to identify the brain basis of this ability, probably because it involves several separate processes. As a first step, we investigated one component process-the ability to recognise mental state terms. In Experiment 1, we tested a group of children with autism (known to have theory of mind deficits) and a control group of children with mental handicap, for their ability to recognise mental state terms in a word list. This was to test if the mental state recognition task was related to traditional theory of mind tests. In Experiment 2, we investigated if in the normal brain, recognition of mental state terms might be localised. The procedure employed single photon emission computerised tomography (SPECT) in normal adult volunteers. We tested the prediction (based on available neurological and animal lesion studies) that there would be increased activation in the orbito-frontal cortex during this task, relative to a control condition, and relative to an adjacent frontal area (frontal-polar cortex). In Experiment 1, the group with autism performed significantly worse than the group without autism. In Experiment 2, there was increased cerebral blood flow during the mental state recognition task in the right orbito-frontal cortex relative to the left frontal-polar region. This simple mental state recognition task appears to relate to theory of mind, in that both are impaired in autism. The SPECT results implicate the orbito-frontal cortex as the basis of this ability.The British Journal of Psychiatry 12/1994; 165(5):640-9. · 6.61 Impact Factor