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Biomedical subjects

S Vicari

Publications and source records attributed to S Vicari.

At least 19 recordsLinked to original sources
PubMed2006

Reading skills and phonological awareness acquisition in Down syndrome.

BACKGROUND: Although reading abilities play a fundamental role in the acquisition of personal autonomy, up until now studies investigating these abilities in Down syndrome (DS) are aimed at defining educational or rehabilitation acquisition. However, studies describing the relationship between reading and phonological awareness in individuals with DS by comparing them to typically developing children often report contradictory results. The aim of this study is to explore reading and phonological awareness skills in a group of participants with DS. METHODS: We administered reading and phonological processing ability tests to 17 DS individuals and to 17 reading-age-matched typically developing children. RESULTS: Concerning reading abilities, participants with DS were impaired on non-word reading and on interpreting accuracy of non-homographic homophones. Their passage comprehension was also limited. Comparable ability was reported in the two groups on irregular word reading and passage reading tasks. Regarding phonological awareness ability, individuals with DS showed lower performances on several tasks, such as rhyming, deletion and syllable segmentation. CONCLUSIONS: People with DS show particular failure on non-word reading, a task where correct decoding is only partially influenced by lexical access or semantic context. Correct non-word reading mainly requires the use of the grapheme-phoneme conversion process. This process is based on the efficiency of phonological awareness abilities, which are partly impaired in people with DS. The rehabilitative implications of these findings are discussed.

Adolescent↗
PubMed2006

[Laparoscopic treatment of liver hydatid cyst: personal technique].

Treatment of liver hydatid cyst is still controversial. Besides medical treatment, interventional radiologic techniques and traditional surgery, recently the laparoscopic approach has been proposed. Laparoscopic treatment of liver hydatid cyst, however, has not been well defined so far and seems to be associated with a recurrence rate from 0 to 9%, in a 3-49 months follow-up. Disadvantages of the laparoscopic approach are difficult control of spillage, peritoneal dissemination of parasites and incomplete aspiration of high density fluid contents of the cyst. The authors have reviewed the literature and describe a personal technique to avoid this disadvantage and to reduce postoperative recurrence rate.

Echinococcosis, Hepatic↗
PubMed2005

Cognitive development in low risk preterm infants at 3-4 years of life.

BACKGROUND: Major neurological handicaps and neuropsychological disturbances are more common in ex-preterm children than their counterparts born at term. OBJECTIVE: To establish in a prospective study whether a characteristic neuropsychological profile exists in ex-preterm children who do not exhibit neurodevelopmental deficits on routine clinical examination. METHODS: Thirty intellectually normal children born preterm (30-34 weeks gestation) without major neurological disabilities and a control group of term children matched for age, sex, and parental educational and occupational status were assessed at 3-4 years of age to obtain a complete neuropsychological profile. Intellectual ability, language comprehension and expression, perceptual and visual motor function, working memory, and attention and behavioural problems were investigated. RESULTS: Even in the absence of major neurological signs, children born preterm achieved lower mean scores than controls on the Stanford-Binet intelligence scale (110.8 v 121, p<0.001), visual perception test (33.8 v 42.7, p<0.001), visual motor integration test (42.6 v 47.4, p = 0.049), memory for location test (8.4 v 9.5, p = 0.007), sustained attention test (41.6 v 51.5, p = 0.009), and the picture vocabulary test (33.3 v 44.7, p = 0.021). CONCLUSIONS: Neuropsychological abnormalities can be detected early in childhood in apparently normal ex-preterm children and are consistent with a growing body of evidence that prematurity may be associated with long term neuropsychological morbidity in childhood and adolescence.

Attention↗
PubMed2005

Do children with developmental dyslexia have an implicit learning deficit?

OBJECTIVE: The purpose of this study was to investigate the effects of specific types of tasks on the efficiency of implicit procedural learning in the presence of developmental dyslexia (DD). METHODS: Sixteen children with DD (mean (SD) age 11.6 (1.4) years) and 16 matched normal reader controls (mean age 11.4 (1.9) years) were administered two tests (the Serial Reaction Time test and the Mirror Drawing test) in which implicit knowledge was gradually acquired across multiple trials. Although both tests analyse implicit learning abilities, they tap different competencies. The Serial Reaction Time test requires the development of sequential learning and little (if any) procedural learning, whereas the Mirror Drawing test involves fast and repetitive processing of visuospatial stimuli but no acquisition of sequences. RESULTS: The children with DD were impaired on both implicit learning tasks, suggesting that the learning deficit observed in dyslexia does not depend on the material to be learned (with or without motor sequence of response action) but on the implicit nature of the learning that characterises the tasks. CONCLUSION: Individuals with DD have impaired implicit procedural learning.

Child↗
PubMed2004

Verbal short-term memory in Down's syndrome: an articulatory loop deficit?

BACKGROUND: Verbal short-term memory, as measured by digit or word span, is generally impaired in individuals with Down's syndrome (DS) compared to mental age-matched controls. Moving from the working memory model, the present authors investigated the hypothesis that impairment in some of the articulatory loop sub-components is at the base of the deficient maintenance and recall of phonological representations in individuals with DS. METHODS: Two experiments were carried out in a group of adolescents with DS and in typically developing children matched for mental age. In the first experiment, the authors explored the reliance of these subjects on the subvocal rehearsal mechanism during a word-span task and the effects produced by varying the frequency of occurrence of the words on the extension of the word span. In the second experiment, they investigated the functioning of the phonological store component of the articulatory loop in more detail. RESULTS: A reduced verbal span in DS was confirmed. Neither individuals with DS nor controls engaged in spontaneous subvocal rehearsal. Moreover, the data provide little support for defective functioning of the phonological store in DS. CONCLUSIONS: No evidence was found suggesting that a dysfunction of the articulatory loop and lexical-semantic competence significantly contributed to verbal span reduction in subjects with DS. Alternative explanations of defective verbal short-term memory in DS, such as a central executive system impairment, must be considered.

Adolescent↗
PubMed2004

Memory development and intellectual disabilities.

Neuropsychological research has permitted different cognitive profiles among subjects with intellectual disabilities (ID) of different etiology to be defined. For example, numerous authors have stressed that the typical language profile for people with Down's syndrome (DS) consists of poor production with greater compromise of morphosyntax than of lexical abilities, but relatively preserved comprehension. Children with Williams' syndrome (WS) often show marked impairment in certain visuospatial abilities (especially praxic-constructive) and relative preservation of both productive and receptive language, at least concerning the phonological elements. These observations seem to support a theoretical approach that considers ID not as a mere slowing of normal cognitive development, but as distinct, individual profiles that can be qualitatively specified. The importance of this approach was shown in several recent studies of memory, especially implicit memory in subjects with ID. Neuropsychological studies suggest insufficient development of the mnemic function in ID at different levels of articulation. Long-term memory has been extensively investigated in people with ID both in the explicit and in the implicit component. According to recent studies, people with ID should show a diffuse impairment of declarative mnesic abilities and a relative preservation of implicit memory. The focus of this study is on the characteristics of long- and short-term memory in children with ID and, particularly, with DS and WS. The results are relevant to knowledge on the qualitative aspects of the anomalous cognitive development in mentally retarded people and the neurobiological substrate underlying this development.

Adolescent↗
PubMed2003

Down syndrome and breastfeeding.

AIM: The aim of the study was to investigate the frequency of breastfeeding among children with Down syndrome. METHODS: The mothers of 560 children with Down syndrome attending four university hospitals in Italy were interviewed and the neonatal clinical records retrieved. Information was collected on the type of infant feeding and on why some mothers had not breastfed their children. Two groups of healthy children whose feeding habits had been previously investigated were recruited as control subjects (1601 and 714, respectively). A paediatrician in each hospital was interviewed about the neonatal admission policy of children with Down syndrome. RESULTS: Among the 560 Down children, 246 (44%) were admitted to the neonatal unit. Compared with the two control groups, children with Down syndrome were significantly more frequently bottle-fed (57% vs 15% and 24%, respectively, odds ratio 7.5, 95% CI 6.0-9.4 and 4.2, 95% CI 3.3-5.4. respectively). Only 30% of infants admitted to the neonatal unit were breastfed. The main reasons reported by the mothers for not having breastfed were infants' illness in infants who had been admitted to the neonatal unit and frustration or depression, perceived milk insufficiency and difficulty with suckling for those babies who had not been admitted to the unit. The paediatricians reported that the admission of a baby with Down syndrome to the neonatal unit could sometimes take place not for medical reasons, but for diagnostic work-up or for a more appropriate diagnosis and to maintain communication with the family. CONCLUSIONS: Down syndrome babies are less frequently breastfed compared with healthy children. Support in breastfeeding should become a relevant point of health supervision for children with Down syndrome.

Bottle Feeding↗
PubMed2002

Morphology and morphometry of the corpus callosum in Williams syndrome: a T1-weighted MRI study.

Williams syndrome (WS) is characterised by a defined genetic aetiology and a specific cognitive profile. It provides an opportunity to examine associations between neuroanatomy, behaviour, and genetics. High-resolution T1-weighted MRI of the brain of 12 patients with WS and 12 normal control subjects were used to estimate the shape and volume of the corpus callosum (CC), as well as the voxel intensity values as a measure its water content. The CC of patients with WS was more convex than that of normal control subjects and overall smaller in volume, particularly in the splenium and in the caudal part of the callosal body. In addition, there were higher ratio values of voxel intensity (i.e. less water content) in the mid-section of the body and the caudal part of the body of the CC. These combined features indicate an aberrant development of the CC in patients with WS and document some of the anatomical abnormalities that may underlie some of the cognitive impairments observed in subjects with WS.

Adolescent↗
PubMed2002

Language acquisition in special populations: a comparison between Down and Williams syndromes.

To investigate the relationship between language acquisition and cognition, we evaluated linguistic abilities in 12 Italian-speaking children with Williams syndrome (WS) and 12 with Down syndrome (DS) of comparable global cognitive level. Another control group included 12 typically developing (TD) children, matched for mental age. Linguistic measures included a parent questionnaire to assess vocabulary, a verbal comprehension test, a sentence repetition test and MLU calculated on spontaneous production. No dissociation was evident between lexical and cognitive abilities, but specific morphosyntactic difficulties emerged both in comprehension and production in children with DS. Individuals with WS, albeit less compromised than DS, also had difficulty in the phrase repetition task and, particularly, using content words. Our results demonstrate that the linguistic abilities of infants with WS are not above their cognitive level and that language development in these special populations is not only delayed, but follows a different developmental trajectory.

Child↗
PubMed2001

Procedural learning deficit in children with Williams syndrome.

The present study was aimed at evaluating implicit memory processes in subjects with Williams syndrome (WS) and comparing them to mental-age (MA) matched normal children. For this purpose, tests of verbal and visuo-perceptual explicit memory, verbal and visual repetition priming as well as procedural learning tasks were administered to 12 WS and 12 MA matched subjects. WS subjects showed a level of repetition priming similar to that of MA normal controls. In contrast, WS children showed a reduced learning rate in the two procedural tasks. Although deficient explicit memory and executive dysfunction cannot be excluded from the performance of WS subjects, these results suggest a specific deficit of procedural learning in this particular group of mentally retarded children. This finding is relevant for our knowledge about the qualitative aspects of the anomalous cognitive development in mentally retarded people and the neurobiological substrate underlying this development.

Adolescent↗
PubMed2001

Implicit versus explicit memory function in children with Down and Williams syndrome.

The present study was aimed at evaluating implicit memory processes in participants with Williams syndrome and comparing them to children with Down syndrome and to mental-age matched typically developing children. For this purpose, tests of verbal and visuo-perceptual explicit memory, verbal and visual repetition priming as well as procedural learning tasks were administered to 12 participants with Williams syndrome, 14 with Down syndrome and 32 typically developing children. Participants with Williams syndrome showed a level of repetition priming similar to that of mental-age typically developing controls. In contrast, children with Williams syndrome showed a reduced learning rate in the two procedural tasks. As regards children with Down syndrome, we document comparable implicit memory abilities. In contrast, regarding explicit memory, typically developing children performed better than individuals with Down syndrome. This finding is relevant for our knowledge about the qualitative aspects of the anomalous cognitive development in individuals with intellectual disabilities and the neurobiological substrate underlying this development.

Child↗
PubMed2001

[Cognitive and linguistic indexes in children with early hemispheric lesion].

Prospective studies of development following early focal brain injury have identified deficits across a range of cognitive, linguistic and affective domains. In most cases these deficits are quite subtle and often not detected on standardized behavioral tests. Nonetheless, more detailed tests of neuropsychological functioning have documented subtle, persistent profiles of impairment. These contrasting findings have been cited in defense of two conflicting beliefs: plasticity and hemispheric equipotentiality theories on one side and early hemispheric specialization on the other. This paper shows some experimental data concerning studies from children with an early focal brain lesion. Our aim is to describe the effects determined by the lesion on the cognitive development and possible diagnostic and rehabilitative strategies.

Brain Diseases↗
PubMed2000

X-linked congenital ataxia: a clinical and genetic study.

We report on a family in which two males are affected with X-linked congenital ataxia (XCA). Clinical manifestations include severe hypotonia at birth, delay of early motor development, slow eye movements, and nonprogressive cerebellar ataxia. The neurological examination excluded a neuromuscular disease, mental retardation, and pyramidal tract involvement. Neuroimaging showed global cerebellar atrophy in both patients that was not evident in the first years of life. The clinical findings in this family are very similar to those in a Russian pedigree [Illarioskin et al., 1996: Ann Neurol 40:75-83] and outline a recognizable phenotype. Linkage studies in our family, using 28 highly polymorphic Généthon microsatellite markers evenly distributed along the X chromosome, excluded a 24 cM interval between DXS990 and DXS424 located within the previous candidate region of 54 cM, reducing the critical interval.

Adult↗
PubMed2000

Developmental dissociation between visual and auditory repetition priming: the role of input lexicons.

Contrasting theories posit the source of verbal repetition priming in the activation of preexisting memory representations in the input lexicons or, alternatively, in the formation of new episodic memory traces. The two hypotheses predict different outcomes from the comparison of developmental rates of visual and auditory verbal repetition priming. The activation theory predicts a developmental dissociation between the early maturation of auditory priming and the later maturation of visuo-verbal priming, contingent upon the discrepant acquisition rates of the auditory and visual input lexicons. The episodic theory, instead, does not make such an assumption. We administered visual and auditory implicit Stem Completion to 40 reading beginners (first-graders), 40 third-graders and 20 fifth-graders. Consistent with previous reports, auditory priming was stable across different age groups. Visual priming and a measure of lexicality in reading, instead, showed a parallel developmental increase passing from reading beginners to third-graders and to fifth-graders. In the overall group, visual priming and the measure of lexicality in reading were significantly associated. These data describe a new developmental dissociation in the memory abilities of normal children and provide further support for the hypothesis that repetition priming for words reflects facilitated access to previously established memory representations.

Auditory Perception↗
PubMed2000

Plasticity and reorganization during language development in children with early brain injury.

Although some studies have reported subtle language deficits following early focal brain lesions (EFBL), most studies find no evidence for differential language outcomes as a function of lesion side or lesion type in children with congenital injuries to one side of the brain. However, recent prospective studies of the first stages of language development in English-speaking children with EFBL have reported greater delays in expressive vocabulary in children with left-hemisphere damage, particularly if the lesion involves left temporal cortex. In the present study, first stages in the development of word production were studied in 43 Italian children with congenital EFBL, between 13 and 46 months of age. As a group, the EFBL children were markedly delayed in expressive vocabulary. Among children who were in the first stage of language learning, delays were significantly greater with left-hemisphere injury. However, this left-right difference was not evident in children who had moved on to the next stage of language development, producing at least some sentences. Discussion centers on the role of developmental plasticity in determining the outcomes of early focal brain injury, suggesting that recovery from initial delays may take place in the early stages of language development, at least for some children.

Brain↗
PubMed2000

Implicit and explicit memory: a functional dissociation in persons with Down syndrome.

This study aimed at investigating implicit and explicit long-term memory functioning in subjects with Down syndrome (DS) compared to Mental-Age (MA) matched normal children. For this purpose, tests of verbal and visuo-perceptual explicit memory, verbal and visual repetition priming and procedural learning tasks were administered to 14 DS and 20 MA subjects. Our results document comparable implicit memory abilities in the two groups. In contrast, regarding explicit memory, normal children performed better than DS individuals. These results reveal a functional dissociation between implicit and explicit memory in subjects with DS. Theoretical and rehabilitative implications are discussed.

Adult↗
PubMed2000

Asynchrony of lexical and morphosyntactic development in children with Down Syndrome.

The aim of this study was to investigate the potential dissociation between mental age and specific aspects of language: lexical and morphosyntactic comprehension and production in different situations and with different measures. Fifteen children with Down Syndrome (DS) (from 4 to 7 years) and fifteen normal controls matched on mental age participated in this study. Children with DS showed generally a lower performance in language abilities with respect to the normal controls. In the two groups no dissociation was evident between lexical and cognitive abilities, but specific morphosyntactic difficulties emerged both in comprehension and production.

Child↗