technetium-tc-99m-exametazime and Autistic-Disorder

Functional changes in the brains of autistic children due to risperidone treatment and theirs relationship to the symptom clusters are yet unknown. In this autistic disorder case series we aimed to comparatively evaluate the clinical findings before and after risperidone treatment, and regional cerebral blood flow (rCBF) findings with 99mTc-hexamethylpropyleneamine oxime (HMPAO) brain SPECT.. Eleven autistic patients (age range: 6-7 years; 4 girls, 7 boys) received risperidone therapy (1.5-2.5 mg d(-1)) and were followed-up for 3 months. All the patients underwent neurologic examinations, psychometric examinations, and SPECT imaging, both at the start of risperidone treatment and 3 months after the treatment started. Clinical observations, and the observations of parents and teachers were recorded. These results were compared with cerebral perfusion indices obtained from SPECT data.. After 3 months of treatment changes in rCBF were observed in various regions and to varying degrees. We observed relationships between clinical symptoms and pre-therapy rCBF findings, and between clinical improvement and rCBF changes.. Findings in the present case series are the first to demonstrate a relationship between clinical improvement and regional perfusion patterns after risperidone treatment. We think that these findings may contribute to the understanding of the neurofunctional mechanisms and hypothetical models of autism.

Topics: Antipsychotic Agents; Autistic Disorder; Cerebrovascular Circulation; Child; Corpus Callosum; Female; Follow-Up Studies; Humans; Male; Regional Blood Flow; Risperidone; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Our subjects consisted of 14 autistic individuals and 14 controls ranging in age from 3 to 37 years. A (99m)Tc HMPAO single photon emission computed tomogram (SPECT) was used to examine blood flow variations between autistic subjects, compared to an age- and gender-matched control group. We found significant hypoperfusion in the prefrontal areas of autistic individuals as compared to normals in every case (p < 0.01). As the age of the autistic individuals increased the hypoperfusion of verbal-associated areas in the left temporal lobe and frontal areas became more evident. The findings were significant at the p < 0.001 level. The changes in perfusion over time correlated with language development and acquisition as individuals matured. We conclude that autistic individuals have a deficiency in prefrontal areas associated with word identification and language formation skills. This subsequently prevents development of true verbal fluency and development in the temporal and frontal areas associated with speech and communication.

Topics: Adolescent; Adult; Age Factors; Aging; Autistic Disorder; Case-Control Studies; Cerebrovascular Circulation; Child; Child, Preschool; Female; Frontal Lobe; Humans; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon

Childhood autism is a developmental disability of unknown origin with probable multiple etiologies. The purpose of this study was to compare the changes of regional cerebral blood flow (rCBF) in autistic and non-autistic controls, and to determine the relationship between rCBF on 99mTc-hexamethylpropylene amine oxime (HMPAO) brain SPECT and the scores of the Ritvo-Freeman Real Life Rating Scale (RLRS), IQ levels, and age of autistic children. Eighteen autistic children (four girls, 14 boys; mean age: 6.13 +/- 1.99 years) and 11 non-autistic controls (five girls, six boys, mean age: 6.5 +/- 3.39 years) were examined using 99mTc-HMPAO brain SPECT. All the children satisfying DSM-IV criteria for autistic disorder were taken into evaluation, and scored by the Ritvo-Freeman RLRS. IQ levels of these children were determined by Goodenough IQ test. Six cortical regions of interest (ROIs; frontal (F), parietal (P), frontotemporal (FT), temporal (T), temporo-occipital (TO), and occipital (O)) were obtained on transaxial slices for count data acquisition. The ratio of average counts in each ROI to whole-slice counts for the autistic children was correlated with the scores of Ritvo-Freeman RLRS. Hypoperfusion in rCBF in autistic children compared with the control group were identified in bilateral F, FT, T, and TO regions. We found no relationship between rCBF on 99mTc-HMPAO brain SPECT and the scores of the Ritvo-Freeman RLRS. There was a relationship between bilateral F regions perfusion on 99mTc-HMPAO brain SPECT and the age of autistic children. There was also a negative correlation between IQ levels and the scores of sensory responses, social relationship to people, and sensory-motor responses. Our results suggest that 99mTc-HMPAO brain SPECT is helpful to locate the perfusion abnormalities but no correlation is found between rCBF on 99mTc-HMPAO brain SPECT and the scores of Ritvo-Freeman RLRS.

Topics: Age Factors; Autistic Disorder; Case-Control Studies; Cerebrovascular Circulation; Cerebrovascular Disorders; Child; Child, Preschool; Cognition Disorders; Female; Humans; Intelligence; Intelligence Tests; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The authors examined specific deficits of cerebral blood perfusion in autistic patients as measured with [(99m)Tc]HMPAO single-photon emission computed tomography (SPECT). The study, conducted in an outpatient clinic setting, included a consecutive series of 30 patients with autism and 14 patients with mental retardation but no autism comparable in chronological age, mental age, height, weight, and head circumference. All participants were examined with a comprehensive psychiatric and neuropsychological battery and received a [(99m)Tc]HMPAO SPECT scan. Autistic patients had significantly lower perfusion than the control group in the following brain regions: right temporal lobe (basal and inferior areas), occipital lobes, thalami, and left basal ganglia. The study demonstrated significant perfusion deficits in specific brain areas of moderately to severely mentally retarded autistic patients.

Topics: Autistic Disorder; Brain; Child; Female; Humans; Intellectual Disability; Magnetic Resonance Imaging; Male; Neuropsychological Tests; Radiopharmaceuticals; Severity of Illness Index; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Autistic disorder is an early and severe developmental disorder characterized by deficits in verbal and nonverbal language, social skills, cognitive functioning and an abnormal repertoire of behaviors. Current research, however, has failed to identify the neurobiological mechanisms that underlie autism or those cortical brain regions, if any, that are abnormal.. We examined regional cerebral blood flow (rCBF) in six young, severely autistic patients. High-resolution brain SPECT with 99mTc-HMPAO was performed while five of the six patients were under general anesthesia. The scans reflected the subjects' rCBF in their usual alert behavioral state, since the tracer was injected at least 15 min prior to anesthesia and is rapidly extracted and fixed in the brain. A computer-automated cortical region of interest (ROI) generator was used to define 12 annular cortical regions (region 1 = left frontal, clockwise to region 12 = right frontal) for count data acquisition. The ratio of average counts in each ROI to whole-slice counts for the autistic patients was compared to age-matched controls using repeated measures (splt-plot) ANOVA statistical analysis for three representative brain levels.. In the autistic patients, cortical regions 3, 4, and 10 were abnormally low at the cortical level canthomeatal (CM) + 3.5 cm. At level CM + 5.5 cm, regions 3, 4, 5 and 10 were abnormally low, and at level CM + 7.5 cm, regions 7 and 9 were also abnormally low. These regions correspond to abnormally low rCBF values located predominately in the temporal and parietal lobes, with the left cerebral hemisphere showing greater rCBF abnormalities than the right.. Our findings suggest that the temporal and parietal lobes have abnormal rCBF in autism. HMPAO brain SPECT in combination with general anesthesia is particularly useful for imaging severely noncompliant patients.

Topics: Adolescent; Adult; Anesthesia, General; Autistic Disorder; Brain; Cerebrovascular Circulation; Child; Female; Humans; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

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.

Topics: Adolescent; Adult; Affective Symptoms; Arousal; Autistic Disorder; Awareness; Brain Mapping; Child; Female; Frontal Lobe; Humans; Intellectual Disability; Male; Organotechnetium Compounds; Oximes; Regional Blood Flow; Semantics; Speech Perception; Technetium Tc 99m Exametazime; Thinking; Tomography, Emission-Computed, Single-Photon

Structural brain abnormalities have recently been discovered using magnetic resonance imaging in infantile autism, a neurodevelopmental disorder of unknown etiology. However, functional neuroimaging studies in autism using positron emission tomography have had conflicting results and have not explained how the known structural brain abnormalities in autism act in a functioning brain to produce autistic behavior. Using a new technology, high-resolution brain single photon emission tomography, we studied and scanned four young adults with infantile autism and four age-matched controls using the labeled ligand 99mTc-D,L-hexamethyl-propylene amine oxime (99mTc-HMPAO). Total brain perfusion was significantly decreased in autism subjects (range, 58% to 72% of controls, p less than or equal to .02). In addition to the globally decreased perfusion, the autism group also had regionally decreased flow in the right lateral temporal and right, left, and midfrontal lobes compared with controls (p less than or equal to .02, Mann-Whitney t-test).

Topics: Adult; Autistic Disorder; Cerebrovascular Circulation; Female; Frontal Lobe; Humans; Male; Organotechnetium Compounds; Oximes; Pilot Projects; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon