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Biomedical subjects

N Amir

Publications and source records attributed to N Amir.

At least 19 recordsLinked to original sources
PubMed1995

Developmental dyscalculia and brain laterality.

The correlation between arithmetic dysfunction and brain laterality was studied in 25 children with developmental dyscalculia (DD). The children were tested on a standardized arithmetic battery and underwent a neurological and neuro-psychological evaluation. A diagnosis of left hemisphere dysfunction (n = 13) was based on right side soft neurological signs, performance IQ (PIQ) > verbal IQ (VIQ), dyslexia and intact visuo-spatial functions. The criteria for right hemisphere dysfunction (n = 12) were left body signs, VIQ > PIQ, impaired visuo-spatial functions and normal language skills. The groups were similar for age, gender, and socio-economic status. Our results showed that both groups scored more than 2 SD below the mean adjusted score on the arithmetic battery, but the left group was significantly worse in 3 areas: mastery of addition/subtraction, complex multiplication and division and visuo-spatial errors (p < 0.05). The data indicate that dysfunction of either hemisphere hampers arithmetic acquisition, but arithmetic impairment is more profound with left hemisphere dysfunction.

Adolescent↗
PubMed1995

Congenital lacticacidemia caused by lipoamide dehydrogenase deficiency with favorable outcome.

A 5-year-old boy had recurrent vomiting and lethargy with lacticacidemia and ketoacidemia since birth. Lipoamide dehydrogenase deficiency was found in muscle and fibroblasts. Therapy with sodium dichloroacetate, thiamine, and carnitine was associated with reduction of the severity and frequency of the decompensation episodes and near normal plasma lactate levels. At 5 years of age, the patient has normal cognitive function and moderate motor impairment.

Acidosis, Lactic↗
PubMed1995

Sinister psychotics. Left-handedness in schizophrenia and affective disorder.

The notion persists that psychotics, particularly schizophrenics, are less right-handed than the general population, and that this deviation is pathophysiologically important in some patients. We assessed handedness and psychopathology in 163 DSM-III schizophrenics, 103 affectives, and 112 normal subjects. Although schizophrenics were less right-handed than normal subjects, this difference was primarily due to more mixed handedness among schizoaffectives. Relationships between handedness and specific psychopathology were uninformative, and we conclude that handedness may not be an important consideration in the study of psychosis.

Adult↗
PubMed1995

Familial microcephaly with severe neurological deficits: a description of five affected siblings.

Autosomal recessive microcephaly is usually characterized by normal developmental milestones and minor neurological deficits. In this report, we describe five siblings in one family with marked microcephaly, intractable seizures, quadriplegia and profound mental retardation. The recurrence risk of microcephaly when associated with devastating neurological deficits, as exemplified by this family, may be high and in such cases, the role of appropriate genetic counseling is of utmost importance.

Child↗
PubMed1993

Intravenous high-dose gammaglobulins for intractable childhood epilepsy.

Immunological mechanisms have been implicated in the pathogenesis of epileptic seizures in some patients and in experimental animal models of epilepsy. A beneficial effect of high dose intravenous gammaglobulin (IVIG) has been demonstrated for some children with intractable epilepsy. In this study we treated 9 children ages 1.1-9.2 years (mean 5.0 years) with intractable epilepsy not responsive to conventional antiepileptic drugs (AEDs) and steroid therapy. Eight children had Lennox-Gastaut syndrome and 1 had complex partial seizures with secondary generalization. Each child received 3 doses of IVIG (200 mg/kg of polyvalent immunoglobulin) on Days 1, 15 and 36. Concomitant AEDs were not changed. Four children had complete remission, 3 had partial response with a more than 50% reduction in seizure frequency and 2 had no response. Onset of response varied from immediate to 7 months after the last injection. No toxicity was noted. Duration of remission was 9 months in 1 case. The other 3 cases have remained in remission to date with a follow up period of 22-26 months. We conclude that IVIG is a safe therapy which appears to be effective in some children with intractable seizures. Children with shorter duration of their seizure disorder (< 1 year) and relatively preserved cognitive function (IQ > 70) appear to have a more favorable response. Larger scale controlled trials are needed to determine the optimal timing and dosage, as well as to identify specific subgroups which may benefit most from IVIG treatment.

Child↗
PubMed1992

Striatal degeneration and spongy myelinopathy in glutaric acidemia.

The neuropathological findings in a 6 1/2-year-old boy with glutaric acidemia (GA) are described, and the pathology of 7 additional literature cases is briefly reviewed. Bilateral striatal degeneration and spongy change of the white matter were the salient features in this case and seem to represent the cardinal pathological features of the disease. Spongy myelinopathy was the result of intramyelinic vacuolation due to splitting of the myelin sheath along the intraperiod line, as illustrated here for the first time in GA. Based on morphological, biochemical and pharmacological data from humans and experimental animals, it is hypothesized that excitotoxin-mediated neuronal damage may account for the striatal degeneration, while toxic effect on myelin metabolism by the metabolic derangement of GA may explain the widespread white matter changes.

Amino Acid Metabolism, Inborn Errors↗
PubMed1992

Variability of clinical presentation in fumarate hydratase deficiency.

A 5-year-old girl with a previous diagnosis of cerebral palsy, nonprogressive psychomotor retardation, and hypotonia was found to excrete excessive fumaric acid in urine. Fumarate hydratase activity in skin fibroblasts was 10% of the control value. This case underscores the clinical heterogeneity of neurometabolic disorders and the importance of organic acid analysis in the diagnosis of static encephalopathy.

Cerebral Palsy↗
PubMed1991

Familial intracranial arachnoid cysts.

Three siblings with intracranial arachnoid cysts are described, two males and one female. One of the males has symmetric, bilateral, temporoparietal convexity cysts, and the others have singular, unilateral cysts. Three additional siblings in the family and other known relatives are clinically unaffected. As far as we know, this is the second reported case of familial intracranial arachnoid cysts and the first involving three siblings. The significance of these cysts and a review of the literature are presented.

Arachnoid Cysts↗
PubMed1990

Late-onset form of partial N-acetylglutamate synthetase deficiency.

A 13-month-old female presented with neurological deterioration of 1 month duration and hyperammonaemia. N-acetylglutamate synthetase activity in the liver was reduced to 33% of the control. A male cousin and a female sister had died following a similar clinical course. This is the first report of late-onset N-acetylglutamate synthetase deficiency. An autosomal-recessive mode of inheritance is suggested.

Acetyltransferases↗
PubMed1990

Cardio-facio cutaneous syndrome: neurological manifestations.

Cardio-facio-cutaneous (CFC) syndrome is a not uncommon syndrome with a characteristic face, mental retardation, abnormal skin and hair and congenital heart disease. We report the 16th case of this syndrome and give details of the spectrum of neurological manifestations in the cases so far reported.

Abnormalities, Multiple↗
PubMed1989

[Organic aciduria in Canavan disease].

3 male and 2 female infants with Canavan disease proven in some by brain biopsy, whose symptoms appeared within the first 4 months of life, are presented. Urinary organic acids were analyzed by gas chromatography/mass spectrometry. All excreted large amounts of N-acetylaspartic acid, probably secondary to decreased activity of its hydrolase. The pathogenetic mechanism is not well understood. Analysis of urinary organic acids can replace brain biopsy in the diagnosis of this condition, and the diagnosis can now be made prenatally.

Acids↗
PubMed1989

Segmentation of EEG during sleep using time-varying autoregressive modeling.

Time-varying AR modeling is applied to sleep EEG signal, in order to perform parameter estimation and detect changes in the signal characteristics (segmentation). Several types of basis functions have been analyzed to determine how closely they can approximate parameter changes characteristic of the EEG signal. The TV-AR model was applied to a large number of simulated signal segments, in order to examine the behaviour of the estimation under various conditions such as variations in the EEG parameters and in the location of segment boundaries, and different orders of the basis functions. The set of functions that is the basis for the Discrete Cosine Transform (DCT), and the Walsh functions were found to be the most efficient in the estimation of the model parameters. A segmentation algorithm based on an "Identification function" calculated from the estimated model parameters is suggested.

Algorithms↗