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Query: UMLS:C0004352 (autism)
 32,579 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this paper we describe a case of severe visual agnosia in a child with an electrophysiological pattern of continuous spike-wave discharges in slow sleep (CSWS) in the occipito-temporal regions. The neuropsychological spectrum related to this phenomenon is discussed. Published paediatric reports associate visual agnosia (i.e. an inability to recognize objects without impairment of visual acuity) mainly with symptomatic occipito-temporal aetiology (e.g. cortical dysplasia, vascular insults) and other neurological symptoms (e.g. autism). We describe a detailed 2 year electrophysiological and neuropsychological follow-up of an 8-year-old boy with sporadic seizures, occipito-temporal CSWS and visual agnosia. The growth and neurological development of the child had been considered as normal, neurological examination did not reveal any focal signs, visual acuity was intact and MRI was normal. First EEG and six consecutive 24 h video EEG recordings during the follow-up of 22 months showed continuous spike-and-wave activity covering over 85% of the non-REM sleep. According to structured neuropsychological tests (Wechsler Intelligence Scale for Children--Third Edition, A Developmental Neuropsychological Assessment (NEPSY), Test of Visual-Perceptual Skills, Corsi block, Hooper Visual Organization Test) the boy had normal verbal intelligence but major deficits in visual perception, especially in object recognition, impaired shape discrimination and detection, and poor copying skills. Attention and executive functions were intact. There were no difficulties in short- or long-term memory. Verbal cues and naming the objects improved visual memory. Tracing the objects with a finger or by moving the head improved object recognition. Currently the boy attends a special school with a rehabilitation plan including neuropsychological and occupational therapies. This case adds a new facet to the spectrum of neuropsychological deficits in children with CSWS. Sleep EEG should be included in the etiological studies of children with specific neuropsychological problems and detailed neuropsychological assessment is needed for diagnostic and rehabilitation purposes.
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PMID:Visual agnosia in a child with non-lesional occipito-temporal CSWS. 1276 57

This study presents the first three-dimensional mapping of cortical sulcal patterns in autism, a pervasive developmental disorder, the underlying neurobiology of which remains unknown. High-resolution T(1)-weighted MRI scans were acquired in 21 autistic (age 10.7 +/- 3.1 years) and 20 normal control (age 11.3 +/- 2.9) children and adolescents. Using parametric mesh-based analytic techniques, we created three-dimensional models of the cerebral cortex and detailed maps of 22 major sulci in stereotaxic space. These average maps revealed anatomic shifting of major sulci primarily in frontal and temporal areas. Specifically, we found anterior and superior shifting of the superior frontal sulci bilaterally (P < or = 0.0003), anterior shifting of the right Sylvian fissure (P = 0.0002), the superior temporal sulcus (P = 0.0006 right, P = 0.02 left) and the left inferior frontal sulcus (P < or = 0.002) in the autistic group relative to the normal group. Less significant sulcal shifts occurred in the intraparietal and collateral sulci. These findings may indicate delayed maturation in autistic subjects in these brain regions involved in functions including working memory, emotion processing, language and eye gaze.
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PMID:Cortical sulcal maps in autism. 1281 88

The Embedded Figures Task involves a search for a target hidden in a more complex visual pattern. The task has been used to study local perception and visual search in a range of normal and pathological populations. After acquired brain damage, impairment on embedded figures is strongly associated with aphasia; in the context of developmental disorder, people with autism or with Asperger's syndrome are reliably found to be better than normal controls on the task. The current study employed functional MRI with healthy volunteers to elucidate the brain regions that are specifically involved in the local search aspects of the Embedded Figures Task. We did so by analyzing the neural activations that are implicated in the task over and above those involved in an easier visual search task and in a straightforward shape recognition task. Significant activations (P < 0.05, corrected) specific in the above sense to the Embedded Figures Task were found in left inferior and left superior parietal cortex and in left ventral premotor cortex (inferior frontal gyrus). By contrast, comparing the overall effect of visual search within geometric figures to pure recognition of geometric shapes revealed more widespread activations in parietal, occipital, cerebellar, and frontal areas bilaterally. The implications of these findings for some developmental and acquired pathologies of perceptual functioning are outlined. We also relate our results to studies of local/global processing in other tasks.
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PMID:In search of the hidden: an fMRI study with implications for the study of patients with autism and with acquired brain injury. 1288 Jul 98

Autism is a neurodevelopmental disorder that severely disrupts social and cognitive functions. MRI is the method of choice for in vivo and non-invasively investigating human brain morphology in children and adolescents. The authors reviewed structural MRI studies that investigated structural brain anatomy and development in autistic patients. All original MRI research papers involving autistic patients, published from 1966 to May 2003, were reviewed in order to elucidate brain anatomy and development of autism and rated for completeness using a 12-item check-list. Increased total brain, parieto-temporal lobe, and cerebellar hemisphere volumes were the most replicated abnormalities in autism. Interestingly, recent findings suggested that the size of amygdala, hippocampus, and corpus callosum may also be abnormal. It is conceivable that abnormalities in neural network involving fronto-temporo-parietal cortex, limbic system, and cerebellum may underlie the pathophysiology of autism, and that such changes could result from abnormal brain development during early life. Nonetheless, available MRI studies were often conflicting and could have been limited by methodological issues. Future MRI investigations should include well-characterized groups of autistic and matched healthy individuals, while taking into consideration confounding factors such as IQ, and socioeconomic status.
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PMID:Brain anatomy and development in autism: review of structural MRI studies. 1451 52

We report the dynamic anatomical sequence of human cortical gray matter development between the age of 4-21 years using quantitative four-dimensional maps and time-lapse sequences. Thirteen healthy children for whom anatomic brain MRI scans were obtained every 2 years, for 8-10 years, were studied. By using models of the cortical surface and sulcal landmarks and a statistical model for gray matter density, human cortical development could be visualized across the age range in a spatiotemporally detailed time-lapse sequence. The resulting time-lapse "movies" reveal that (i) higher-order association cortices mature only after lower-order somatosensory and visual cortices, the functions of which they integrate, are developed, and (ii) phylogenetically older brain areas mature earlier than newer ones. Direct comparison with normal cortical development may help understanding of some neurodevelopmental disorders such as childhood-onset schizophrenia or autism.
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PMID:Dynamic mapping of human cortical development during childhood through early adulthood. 1514 81

The brain activation of a group of high-functioning autistic participants was measured using functional MRI during sentence comprehension and the results compared with those of a Verbal IQ-matched control group. The groups differed in the distribution of activation in two of the key language areas. The autism group produced reliably more activation than the control group in Wernicke's (left laterosuperior temporal) area and reliably less activation than the control group in Broca's (left inferior frontal gyrus) area. Furthermore, the functional connectivity, i.e. the degree of synchronization or correlation of the time series of the activation, between the various participating cortical areas was consistently lower for the autistic than the control participants. These findings suggest that the neural basis of disordered language in autism entails a lower degree of information integration and synchronization across the large-scale cortical network for language processing. The article presents a theoretical account of the findings, related to neurobiological foundations of underconnectivity in autism.
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PMID:Cortical activation and synchronization during sentence comprehension in high-functioning autism: evidence of underconnectivity. 1521 13

Past functional MRI (FMRI) studies of autism have reported reduced activation in response to the faces of strangers primarily in the 'fusiform face area' (FFA). An alternative and potentially stronger test of FFA function in autism is one that attempts to affect levels of FFA activity using factors believed to modulate function in this brain region, such as face familiarity and the perception of face identity. The current study presented personally meaningful faces, such as mother and co-worker, as well as stranger faces in a rapid event-related FMRI design. Seven autistic and nine normal control adults participated and pressed a button in response to all female faces. A deconvolution analysis revealed significant FFA activity in response to familiar and stranger faces in both autism and normal control groups. Individuals with autism also showed greater fusiform activity in response to familiar faces than stranger faces, as well as the prototypical right hemisphere dominance in response to both types of faces. Normal subjects showed additional activation to familiar faces in the posterior cingulate, amygdala and medial frontal lobes, including the anterior cingulate. Subjects with autism showed a similar, but more limited, network in response to familiar faces. This network included the amygdala and implies that this structure, involved in multiple socio-emotional functions, can be responsive in autism in the presence of stimuli that represent high reward value, such as mother's face. Furthermore, the presence of a distinct network to process familiar faces in autism, one that included limbic structures and was not found in response to the faces of strangers, suggests socio-emotional processing in autism. A potentially noteworthy trend, however, was evidence for a reduction in medial frontal lobe function in the autism group. The main finding of FFA activity in autism stands in contrast to most past FMRI studies of face processing in this disorder. This positive result may reflect the use of personally significant faces that enhanced attention and motivation in the autistic participants. Furthermore, given the proposed role of the FFA in establishing person identity, the use of almost a dozen different personally familiar faces for each participant (totalling 32 non-repeating faces) may have additionally maximized FFA involvement. Therefore, dysfunction in the FFA found in other studies of autism may reflect defects in systems that modulate the FFA, rather than the FFA itself.
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PMID:The brain response to personally familiar faces in autism: findings of fusiform activity and beyond. 1531 75

The underlying neurobiology of autism, a severe pervasive developmental disorder, remains unknown. Few neocortical brain MRI abnormalities have been reported. Using rest functional brain imaging, two independent studies have described localized bilateral temporal hypoperfusion in children with primary autism. In order to search for convergent evidence of anatomical abnormalities in autistic children, we performed an anatomical MRI study using optimized whole-brain voxel-based morphometry (VBM). High-resolution 3-D T1-weighted MRI data sets were acquired in 21 children with primary autism (mean age 9.3 +/- 2.2 years) and 12 healthy control children (mean age 10.8 +/- 2.7 years). By comparing autistic children to normal children, we found bilaterally significant decreases of grey matter concentration located in superior temporal sulcus (STS) (P < 0.05 corrected, after small volume correction; SVC). Children with autism were also found to have a decrease of white matter concentration located in the right temporal pole and in cerebellum (P < 0.05, corrected) compared to normal children. These results suggest that autism is associated with bilateral anatomical abnormalities localized in the STS and are remarkably consistent with functional hypoperfusion previously reported in children with autism. The multimodal STS areas are involved in highest level of cortical integration of both sensory and limbic information. Moreover, the STS is now recognized as a key cortical area of the "social brain" and is implicated in social perceptual skills that are characteristically impaired in autism. Therefore, the convergent anatomical and functional temporal abnormalities observed in autism may be important in the understanding of brain behavior relationships in this severe developmental disorder.
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PMID:Superior temporal sulcus anatomical abnormalities in childhood autism: a voxel-based morphometry MRI study. 1532 84

Chromosome 10p terminal deletions have been associated with a DiGeorge like phenotype. Haploinsufficiency of the region 10p14-pter, results in hypoparathyroidism, sensorineural deafness, renal anomaly, that is the triad that features the HDR syndrome. Van Esch (2000) identified in a HDR patient, within a 200 kb critical region, the GATA3 gene, a transcription factor involved in the embryonic development of the parathyroids, auditory system and kidneys. We describe a new male patient, 33-year-old, with 10p partial deletion affected by hypocalcemia, basal ganglia calcifications and a severe autistic syndrome associated with mental retardation. Neurologically he presented severe impairment of language, hypotonia, clumsiness and a postural dystonic attitude. A peripheral involvement of auditory pathways was documented by auditory evoked potentials alterations. CT scan documented basal ganglia calcifications. Hyperintensity of the lentiform nuclei was evident at the MRI examination. Renal ultrasound scan was normal. Haploinsufficiency for GATA3 gene was documented with FISH analysis using cosmid clone 1.2. Phenotypic spectrum observed in del (10p) is more severe than the classical DGS spectrum. GATA3 has been found to regulate the development of serotoninergic neurons. A serotoninergic dysfunction may be linked with autism in this patient.
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PMID:Chromosome 10p deletion in a patient with hypoparathyroidism, severe mental retardation, autism and basal ganglia calcifications. 1533 74

Due to the relatively late age of clinical diagnosis of autism, the early brain pathology of children with autism has remained largely unstudied. The increased use of retrospective measures such as head circumference, along with a surge of MRI studies of toddlers with autism, have opened a whole new area of research and discovery. Recent studies have now shown that abnormal brain overgrowth occurs during the first 2 years of life in children with autism. By 2-4 years of age, the most deviant overgrowth is in cerebral, cerebellar, and limbic structures that underlie higher-order cognitive, social, emotional, and language functions. Excessive growth is followed by abnormally slow or arrested growth. Deviant brain growth in autism occurs at the very time when the formation of cerebral circuitry is at its most exuberant and vulnerable stage, and it may signal disruption of this process of circuit formation. The resulting aberrant connectivity and dysfunction may lead to the development of autistic behaviors. To discover the causes, neural substrates, early-warning signs and effective treatments of autism, future research should focus on elucidating the neurobiological defects that underlie brain growth abnormalities in autism that appear during these critical first years of life.
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PMID:Brain development in autism: early overgrowth followed by premature arrest of growth. 1536 65


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