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Biomedical subjects

E Mercuri

Publications and source records attributed to E Mercuri.

At least 109 records · Page 6Linked to original sources

Visual function in full-term infants with hypoxic-ischaemic encephalopathy.

Thirty-one full term infants with hypoxic-ischaemic encephalopathy (HIE) were studied with a battery of tests designed to evaluate visual function in infancy and with serial MRI. Their age ranged between 5 and 31 months. The aim of the study was to evaluate whether the degree of HIE or the site and size of lesions on MRI could predict visual outcome. Twenty of the 31 infants studied showed abnormal results on at least one of the visual tests used. While visual function was generally normal in grade I HIE and severely impaired in grade III, visual outcome was variable in grade II. MRI findings were better predictors of visual impairment than the degree of HIE. Normal scans tended to be associated with normal visual function, irrespective of the severity of HIE. All but one of the infants with diffuse hemispheric involvement also showed multiple visual abnormalities. The concomitant involvement of basal ganglia was always associated with more severe visual outcome. These results suggest that infants with generalised lesions secondary to global insults are at high risk of severe visual impairment even in presence of normal acuity and require early assessment of various aspects of visual function.

Basal Ganglia↗

Minor neurological signs and perceptual-motor difficulties in prematurely born children.

AIM: To examine the spectrum of neurological dysfunction and perceptual-motor difficulties at school age in a cohort of prematurely born children, and the relation of these measures to neonatal brain lesions, intelligence quotient, and behavioural adjustment. METHOD: One hundred and eighty three children were tested at the age of 6 years using Touwen's Examination of the Child with Minor Neurological Dysfunction, the Movement Assessment Battery for Children (Movement ABC), the Developmental Test of Visual-Motor Integration (VMI), British Ability Scales, and Rutter Scales. RESULTS: Twenty six children had definite cerebral palsy and one was blind. Of the remaining 156, the proportions falling below the 15th centile point were 31% on Touwen's Examination, 44% on the Movement ABC, and 17% on the VMI. Forty two passed all three tests. No child with a normal ultrasound scan developed cerebral palsy, whereas nearly all those with major lesions did. Minor lesions, however, were not generally predictive of later outcome. Correlations between the tests were generally low. CONCLUSIONS: These findings stress the need to assess neurological and perceptual motor functioning separately at school age and to monitor relationships with other aspects of development.

Analysis of Variance↗

Basal ganglia damage and impaired visual function in the newborn infant.

AIM: To examine the effects of early lesions in the visual pathway on visual function; and to identify early prognostic indicators of visual abnormalities. METHODS: The visual function of 37 infants with perinatal brain lesions on magnetic resonance imaging was assessed using behavioural and electrophysiological variables. RESULTS: Normal visual behaviour was observed in most infants with large bilateral occipital lesions, but all the infants with associated basal ganglia involvement had abnormal visual function. Visual abnormalities were also present in six infants with isolated basal ganglia lesions. CONCLUSIONS: These observations suggest that basal ganglia may have an integral role in human visual development and that their presence on neonatal MRI could be an early marker of abnormal visual function.

Basal Ganglia↗

[Local anesthesia in the surgery of inguinal hernia. Technical notes].

Routine use of local anaesthesia associated with tension-free hernioplasty in surgical treatment of inguinal hernia allows an immediate patient walking and prompt discharge from the hospital unit: with this technique 89 cases in two years were operated. The anaesthesia-related discomforts and complications are minimal. The addition of an intravenous sedative (propofol) premis to extend this approach to anxious patients too.

Anesthesia, Local↗

Visual function of prematurely born children with and without perceptual-motor difficulties.

The relationship between visual and perceptual-motor abilities at 6 years of age was investigated in a cohort of 141 prematurely born children without cerebral palsy. Visual acuity was assessed using the Sonksen-Silver Acuity System and stereopsis with the Titmus stereo test. Perceptual motor abilities were evaluated using the Movement Assessment Battery for Children and the Developmental Test of Visual-Motor Integration. The results showed a higher incidence of abnormalities both of linear acuity and stereopsis in the study group when compared to a group of reference children. Whereas abnormalities of linear acuity were not associated with perceptual-motor difficulties, abnormal stereopsis was significantly associated with poor performance on both perceptual-motor tests. Our results suggest that infants born preterm, even in the absence of other major neurological signs, are at risk for abnormal visual function and perceptual-motor difficulties. As these could interfere with everyday life and school performance, a longitudinal assessment of both areas of competencies is recommended so that diagnosis and possible intervention can take place as early as possible.

Brain Diseases↗

Sequential study of central and peripheral nervous system involvement in an infant with merosin-deficient congenital muscular dystrophy.

Diffuse white matter changes on brain imaging and peripheral neuropathy are associated features of merosin-deficient congenital muscular dystrophy (CMD). In this report we describe the early manifestation and evolution of brain changes, and the involvement of the peripheral nervous system in a female infant with merosin-deficient CMD diagnosed in the neonatal period who had sequential clinical, neurophysiological and magnetic resonance imaging (MRI) assessment. Both MRI and nerve conduction velocity in the first week of life failed to demonstrate any abnormality. By 6 months of age both nerve conduction and MRI were abnormal. White matter changes became more evident on a further scan at 1 yr of age and this pattern remained unchanged on the following scan performed at 17 months of age. Our findings suggest a failure in the physiological maturation process of myelination of both the central and peripheral nervous system.

Central Nervous System Diseases↗

Visual outcome in children with congenital hemiplegia: correlation with MRI findings.

Fourteen children with congenital hemiplegia were studied with a detailed assessment of various aspects of vision (linear acuity, stereopsis, visual fields) and MRI. The aim of this study was to evaluate the effect of a congenital lesion on visual function. The results showed a very high incidence (78%) of children who had abnormal results on at least one of the visual tests. Visual abnormalities were not correlated with the clinical severity of hemiplegia or with a specific pattern of lesion on MRI. Similarly no constant association could be found between visual structures (optic radiations and primary visual cortex) and visual function. Finally, our results would suggest that all the children with congenital hemiplegia need to be investigated irrespective of the clinical severity or of the type or the extent of the lesion. This would help to identify children with minor visual abnormalities which can affect everyday life performance.

Adolescent↗

Evaluation of the corpus callosum in clumsy children born prematurely: a functional and morphological study.

The aim of this study was to evaluate the incidence of functional and neuroradiological abnormalities of the corpus callosum in a group of 21 prematurely born children (GA < 34 weeks) who were found to be "clumsy" on the Movement Assessment Battery for Children at 6 years of age. All children underwent functional and morphological assessment of the corpus callosum. The functional assessment included tests of somesthesis, diadochokinesis and repetitive finger tapping. The morphology of the corpus callosum was evaluated on midsagittal MRI. Thirteen of the 21 clumsy children showed morphological abnormalities which were significantly associated with functional abnormalities. Morphological changes of the corpus callosum were also significantly associated with lesions on both neonatal ultrasound and late MRI. Our results support the view that morphological abnormalities of the corpus callosum are frequent in children born prematurely. The association between these abnormalities and lesions on US or MRI suggests that they are likely to be secondary to pre- or perinatal lesions.

Agenesis of Corpus Callosum↗

Visual function and perinatal focal cerebral infarction.

AIMS: To evaluate the visual function of infants with perinatal cerebral infarction in whom the site and size of the lesion has been determined using magnetic resonance imaging (MRI). METHODS: Twelve infants with cerebral infarction on MRI were studied with a battery of tests specifically designed to evaluate visual function in infancy. This included tests: for visual attention (fixation shifts); of cerebral asymmetry (optokinetic nystagmus, visual fields); for assessment of acuity (forced choice preferential looking); and neurophysiological measures of vision (phase reversal and orientation reversal visual evoked potential). RESULTS: A considerable incidence of abnormalities on at least one of the tests for visual function used was observed. The presence or severity of visual abnormalities could not always be predicted by the site and extent of the lesion seen on imaging. CONCLUSIONS: Early focal lesions affecting the visual pathway can, to some extent, be compensated for by the immature developing brain. These data suggest that all the infants presenting with focal lesions need to be investigated with a detailed assessment of various aspects of vision.

Cerebral Infarction↗

Mechanisms and evolution of the brain damage in neonatal post-hemorrhagic hydrocephalus.

There are three main mechanisms of poor outcome in children with post-hemorrhagic hydrocephalus: (1) brain injuries due to ventricular dilatation, (2) shunt-related complications, and (3) primary cerebral hypoxic-ischemic and hemorrhagic lesions. The authors give a short up-to-date report, focusing mainly on the third mechanism, with reference to personal studies.

Brain Injuries↗

Somatosensory and visual evoked potentials in congenital muscular dystrophy: correlation with MRI changes and muscle merosin status.

Congenital muscular dystrophy comprises a heterogeneous group of disorders, that have in common an early onset and a dystrophic picture on the muscle biopsy. The "pure" form of congenital muscular dystrophy is not associated with severe mental retardation or structural changes in the brain, though white matter changes on brain imaging have been detected in a significant proportion of cases. In this study we evaluated the incidence of sensory abnormalities (somatosensory and visual evoked responses) in a group of 17 patients with "pure" congenital muscular dystrophy and correlated the results of the evoked responses with the presence or absence of white matter changes on brain magnetic resonance imaging. Our results show close correlation between the presence of MRI white matter changes and abnormalities in the sensory evoked potentials. Conversely, all patients with normal brain MRI had normal somatosensory evoked potentials (SEP). Visual evoked potentials were less sensitive than somatosensory evoked potentials in detecting abnormalities in children with white matter changes on MRI. With the recent discovery of deficiency in merosin expression in the skeletal muscle of a subgroup of patients with CMD, we also correlated the presence or absence of white matter changes and the SEP responses with the merosin status. The results indicate that all merosin-negative patients had abnormal SEP as well as abnormal MRI, whilst no patient with normal merosin expression had an abnormal scan or abnormal SEP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Minor neurological and perceptuo-motor deficits in children with congenital muscular dystrophy: correlation with brain MRI changes.

Diffuse white matter changes on magnetic resonance imaging (MRI) have been a consistent feature in some children with the "pure" form of congenital muscular dystrophy (CMD) in which there are no structural changes in the brain or severe mental retardation. The aim of this study was to assess fine motor and perceptuo-motor abilities in children with CMD with and without MRI changes. Twenty-two children with "pure" CMD were investigated with a standard neurological examination and a battery of tests (Manual dexterity from the Movement ABC, test of visual-motor integration, Zurich Neuromotor test) which have already been used to detect minor neurological signs related to white matter changes. The cohort was then divided in two groups for analysis depending on the presence or the absence of diffuse white matter changes. A significant difference was found for all the tests between the group of the CMD children with normal MRI and the group with diffuse white matter changes. The manual dexterity and the Zurich Neuromotor tests showed a greater sensitivity than the test of visual-motor integration, which had some false negatives. It is of interest that in the group with diffuse white matter changes the presence of contractures or weakness did not seem to affect the quality of the performance; all these children scored abnormally on the test, irrespective of the severity or the extent of contractures and weakness. In contrast, in children with normal MRI severe contractures and weakness did affect the performances. Our results demonstrate that perceptuo-motor difficulties and minor neurological soft signs are a consistent feature in CMD children with diffuse MRI changes but not with normal MRI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

The effect of behavioural states on visual evoked responses in preterm and full-term newborns.

There is no general agreement about the influence of the behavioural states on the visual evoked responses. In the present study visual evoked potentials (VEP) were recorded in 6 preterm and 6 full-term newborns in the different behavioural states. A significant increase in the amplitude was observed from sleep to awake states in both preterm and full-term infants. The results supply information in favour of the utility of the behavioural assessment when VEP are recorded. It reduces the variability of the results providing for more reliable normative data.

Evoked Potentials, Visual↗

Ischaemic and haemorrhagic brain lesions in newborns with seizures and normal Apgar scores.

Serial ultrasound scans and conventional and diffusion weighted magnetic resonance imaging (MRI) were performed on 16 neonates who presented with seizures. The Apgar scores were normal and subsequently no metabolic or infective cause could be found. The aim of the study was to evaluate the extent to which early sequential imaging can elucidate the cause of seizures in apparently neurologically normal infants. Fourteen of the infants had haemorrhagic or ischaemic lesions on MRI and these were detected by ultrasound scanning in 11. Early ultrasound scanning detected the haemorrhagic lesions but the ischaemic lesions were often not seen until the end of the first week of life. Early MRI, however, was able to detect all the ischaemic lesions. The evolution of the insult could be timed by using serial ultrasound scans and a combination of diffusion weighted and conventional MRI during the first week of life, confirming a perinatal insult even in the absence of fetal distress. Although the aetiology of these lesions remains obscure, serial ultrasound scans will detect the presence of cerebral lesions in neonates presenting with isolated seizures but additional MRI sequences will give better definition on type, site, and extent of the pathology.

Apgar Score↗

Neurological 'soft' signs may identify children with sickle cell disease who are at risk for stroke.

UNLABELLED: Stroke is one of the most frequent complications of sickle cell disease (HbSS), occurring in 7-17% of children. Recent studies recognized more minor lesions on MRI, not associated with clinical signs on standard neurological examination, which however have been found to be a risk factor for developing stroke later. The aim of this study was to evaluate whether minor lesions observed on imaging could be associated with 'soft' neurological signs not detectable on conventional neurological examination. Fourteen children with HbSS were assessed with MRI, standard neurological examination and evaluation of 'soft' signs (Zurich Neuromotor Test) and motor function (Movement ABC). Eight of the 14 children scanned showed lesions on MRI but only 3 of the full cohort were abnormal on standard neurological examination. However, all of the eight children with MRI lesions also showed abnormal signs on at least one of the two tests (Zurich and Movement ABC). All the children with normal MRI were normal on all the tests performed. The sensitivity of Zurich Neuromotor Test and Movement ABC in the group of children with MRI lesions is 0.88 and 0.75, respectively, and increases to 1 when the two tests are used together. The specificity of both tests is 1 even when the tests are used separately. CONCLUSION: Although the number of cases is small, 'soft' signs may reliably identify the presence of even minor MRI lesions, allow the evaluation of the global incidence of major and minor neurological signs and may also help to identify the population at risk for developing strokes. This population could then be closely monitored and benefit from early intervention.

Adolescent↗

Neonatal neurology, past present and future. A window on the brain.

Interest in the neurology of the newborn has been largely stimulated by the new advances of imaging; CT, cranial ultrasonography and MRI which for the first time allowed diagnosis of brain lesions in the live infant which in the past could only be made by post mortem examinations. (Ultrasound in particular, as it is safe, cheap and portable has been eminantly suitable for routine use in the nurseries to study the incidence, timing and evolution of the lesions in the neonatal period. While MRI is expensive and more difficult to perform it gives superb anatomical definition and is also safe for repeated examinations. It is thus very suitable to follow the evolution of the lesions into infancy). The aim of this presentation is to illustrate how an integrated approach with the combined use of imaging and clinical evaluations lead to a better understanding of antenatal and perinatal factors which may be responsible for the production of these lesions on one hand and the impact of these lesions on later development on the other.

Brain Diseases↗

Multimodality evoked responses in the neurological assessment of the newborn.

In recent years increased attention has been devoted to evoked potentials (EP) in newborns. This paper reviews the literature and data from our research group in an attempt to assess the diagnostic and prognostic value of evoked responses in the first weeks of life and their use in different age-specific clinical conditions. The results show that EP are a very sensitive measure of the integrity of the sensory pathways. They make it possible to follow normal physiological maturation and the abnormalities of development resulting from neurological lesions. Repeated measurements of visual evoked potentials and somatosensorial evoked potential are prognostically useful in term infants, but seem much more limited in preterm newborns in predicting neurodevelopmental outcome.

Evoked Potentials↗