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M Zilbovicius

Publications and source records attributed to M Zilbovicius.

29 records · Page 2Linked to original sources
PubMed1995

Delayed maturation of the frontal cortex in childhood autism.

OBJECTIVE: The authors investigated the metabolic maturation of the frontal cortex in pre-school autistic children. METHOD: Regional cerebral blood flow (CBF) in five children with primary autism diagnosed according to the DSM-III-R criteria was studied longitudinally. Regional CBF in each of the autistic children was measured with single photon emission computed tomography twice during their development: at the age of 3-4 years and 3 years later. At each stage, the autistic children were compared to an age-matched comparison group of five nonautistic children with normal development. RESULTS: A transient frontal hypoperfusion was found in the autistic children at ages 3-4 years; this corresponded to the pattern of perfusion observed in much younger normal children. By the ages of 6-7, the autistic children's frontal perfusion had attained normal values. CONCLUSIONS: Since CBF patterns in children are related to maturational changes in brain function, these results indicate a delayed frontal maturation in childhood autism. Such a delayed brain maturational process is consistent with the clinical data and cognitive performance of autistic children.

Adolescent↗
PubMed1994

Movement- and task-related activations of motor cortical areas: a positron emission tomographic study.

Using repeated measurements of regional cerebral blood flow with positron emission tomography, we investigated the regional cortical activations induced in 10 normal subjects, by two different finger motor tasks, i.e., a repeated flexion-extension of all fingers and a repeated flexion-extension of the middle finger. The all-finger movement only activated the primary sensorimotor cortex (SM) and the supplementary motor area (SMA) contralateral to the movement. However, the activation of the SMA was clearly task related during this motor task, because it was only observed when the movement was triggered by an auditory cue but not when it was self-paced. The middle finger movement was performed during self-paced conditions. It induced a much more complex pattern of activation than the all-finger movement, characterized by a high degree of SM and SMA activation contralateral to the side of the movement, as well as a slight ipsilateral activation of these areas. We suggest that this pattern of cortical activation may reflect the process of individuating finger movement or the early stages of motor learning of this unusual and technically difficult movement. Our data also confirm that the SM activation is closely linked to the intrinsic parameters of the movement; while the SMA may be activated by different aspects of the movement realization and preparation.

Adult↗
PubMed1994

Abnormal regional CBF response in left hemisphere of dysphasic children during a language task.

This study used xenon 133 inhalation and single-photon computed tomography to measure regional cerebral blood flow during a quiet resting condition, a simple auditory task, and an auditory phonemic discrimination task in 3 age-matched groups of children suffering from developmental language disabilities: expressive dysphasia, expressive-receptive dysphasia, and attention-deficit hyperactivity disorder. An absence of left hemisphere activation was observed in the expressive-receptive group during the phonemic discrimination task as compared to both expressive and attention-deficit hyperactivity disorder children, together with an absence of left inferior parietal region activation in dysphasics as compared to hyperactive children. These results favor the hypothesis of an abnormal lateralization for language in dysphasic children and point toward possible different pathologic localizations in the different clinical subtypes of dysphasia.

Aphasia↗
PubMed1993

Theoretical aspects of the study of benzodiazepine receptors in infantile autism.

This paper is part of a special section on 'psychopharmacotherapy in children' and focuses on benzodiazepine receptors in autism. Infantile autism in an early and pervasive developmental disorder described by Kanner in 1943. Anatomical, pathological and magnetic resonance imaging studies have indicated changes in the cerebellum and hippocampus of autistic subjects. Given the numerical importance and diffuse benzodiazepine receptors, their study by functional brain imaging methods in vivo could be value in cases of infantile autism as a gauge of neuronal potentiality. The main data concerning benzodiazepine complex are presented. The relations between these data and the neurophysiological hypotheses of autism are discussed.

Adolescent↗
PubMed1992

Different mental imagery abilities result in different regional cerebral blood flow activation patterns during cognitive tasks.

Using regional cerebral blood flow (rCBF) imaging, two populations having high and low imagery abilities were compared at rest and while performing two cognitive tasks: silent verb conjugation and mental imagery. The imagery task produced an rCBF increase in the left visual association and left frontal cortices in both groups. Differences between high and low imagers were observed on global and regional flow responses to cognitive tasks: low imagers showed a whole cortex CBF increase during both tasks; high imagers showed a right dominance in the visual association cortex in all conditions, and in the parietal association cortex at rest.

Adult↗
PubMed1992

Regional cerebral blood flow in childhood autism: a SPECT study.

OBJECTIVE: The authors investigated a possible cortical brain dysfunction associated with infantile autism. METHOD: They measured regional cerebral blood flow with single photon emission computed tomography (SPECT) and xenon-133 in 21 children with primary autism (according to DSM-III-R criteria). Five cortical brain areas including frontal, temporal, and sensory association cortices were examined in order to test the recent hypothesis of cerebral dysfunction in primary autism. Anatomical references for each subject were obtained with computerized tomography or magnetic resonance imaging and were used to delimit the regions of interest for SPECT analysis. RESULTS: When the results from the group with primary autism were compared with an age-matched group of nonautistic children with slight to moderate language disorders (N = 14), no cortical regional abnormalities were found. CONCLUSIONS: It appears that there is no regional cortical dysfunction in primary autism; however, in light of methodological limitations, one cannot exclude the possibility of more localized or subcortical brain dysfunctions in autism.

Autistic Disorder↗
PubMed1992

In-vivo SPECT imaging of D2 receptor with iodine-iodolisuride: results in supranuclear palsy.

We assessed the potential use of [123I]iodolisuride (ILIS), a new iodine ergolene derivative, to study human striatal D2 dopamine receptors with SPECT. In normal subjects, we found that the tracer accumulated preferentially in striatum. This was prevented by high doses of haloperidol. The striatal accumulation was maximal between 60 and 180 min after injection. The striatum-to-cerebellum radioactivity concentration ratio as an index of specific binding, measured 60 min after injection, was 1.52 +/- 0.19 (mean +/- s.d.) in controls and 1.36 +/- 0.11 in patients with supranuclear palsy (p less than 0.03). Our results show that ILIS may be used to study D2 receptors with SPECT. In-vivo changes of D2 receptors in human brain may be detected with this method.

Adult↗
PubMed1992

Changes in regional cerebral blood flow during brain maturation in children and adolescents.

Regional cerebral blood flow (rCBF) was studied by SPECT using 133Xe in 42 children, aged 2 days to 19 years, considered as neurologically normal. rCBF was measured on cortical regions and on the cerebellum and thalamus. Curves for reference values and standard deviation were defined for each region. At birth, cortical rCBFs were lower than those for adults; after birth they increased until 5 or 6 yr of age to values 50%-85% higher than those for adults and thereafter decreased, reaching adult levels between 15 and 19 yr. Neonatal values of rCBF on cerebellum and thalamus were slightly higher than adult level, but not significantly; after age 1, they followed the common pattern for cortical curves. When rCBFs were expressed in percent global CBF, they were lower at birth than adult levels in the cortex, then increased and reached a plateau corresponding to the adult value before the second year of age. The time needed to reach normal adult values differed for each cortical region. The shortest time was found on the primary cortex and the longest on the associative cortex. Cognitive development of the child seems to be related to changes in blood flow of the corresponding brain regions.

Adolescent↗
PubMed1991

A serial study of regional cerebral blood flow before and after hemispherectomy in a child.

Hemimegalencephaly (HME) is a severe unilateral brain malformation the prognosis of which may be improved by hemispherectomy. HME also provides a unique opportunity to compare normal and pathological hemispheric function in the same patient. We performed a serial functional cerebral imaging study in a child suffering from a neuropathologically confirmed left HME. He was hemispherectomized at 11 months because of intractable epilepsy; this led to cessation of seizures and dramatic psychomotor improvement. Regional cerebral blood flow (rCBF) was studied at 1, 7, 10, 12 and 25 months with single photon computed tomography (SPECT) using 133-Xenon and with simultaneous EEG recording. At one month of age SPECT was performed ictally. During left EEG discharges, rCBF was 40% higher on the left hemisphere than on the right, even in occipital and frontal regions, usually immature at this age. A crossed cerebellar hyperperfusion was also found. At 7 and 10 months, SPECT was performed interictally; rCBF was 45% lower in the left hemisphere than in the right. During follow-up, global and regional CBF values showed normal levels and normal maturation in the right hemisphere except for a mild and transient decrease observed one month after hemispherectomy. SPECT provides an additional procedure for studying hemispheric function in vivo. Serial SPECT imaging may be useful for the preoperative and postoperative evaluation in unilateral cerebral malformation.

Brain↗
PubMed1989

Regional cerebral blood flow by SPECT imaging in Sturge-Weber disease: an aid for diagnosis.

Regional cerebral blood flow (rCBF) was studied using SPECT (single photon emission computed tomography) with 133-Xenon in 13 patients with confirmed Sturge-Weber disease, aged 9 months to 18 years. CT scan, performed at the same time, showed evident cerebral angioma in 10 but not in three. A marked hypoperfused area was found in all patients, ranging from -32% to -72% and of the same location as the CT signs. The hypoperfusion seems to result from post ictal phenomenon as well as from chronic ischaemia. SPECT imaging is therefore a sensitive method for visualising intracranial angioma in Sturge-Weber disease and it provides an aid for diagnosis when a CT scan is not reliable.

Adolescent↗