Gender differences in early stages of language development. Some evidence and possible explanations

It is a common feeling that girls speak earlier than boys; however, whether or not there are gender differences in early language acquisition remains controversial. The present paper aims to review the research on gender effects in early language acquisition and development, to determine whether, and from which age, an advantage for girls does eventually emerge. The focus is on the production of actions and communicative gestures, and early lexical comprehension and production, by girls and boys. The data from various studies that were conducted with direct and indirect tools suggest that some gender differences in actions, gesture, and lexical development depend on the interactions of different factors. Studies differ in terms of age ranges, sample sizes, and tools used, and the girl advantage is often slight and/or not evident at all ages considered. Statistical significance for gender differences appears to depend on the greater individual variability among boys, with respect to girls, which results in a greater number of boys classified as children with poor verbal ability. Biological (e.g., different maturational rates), neuropsychological (e.g., different cognitive strategies in solving tasks), and cultural (e.g., differences in the way parents relate socially to boys and girls) factors appear to interact, to create feedback loops of mutual reinforcement.

The Italian Deaf Community at the Time of Coronavirus

The present paper will explore the impacts of the recent pandemic crisis on the Italian Deaf community, as a linguistic minority. Recent research has shown that minorities are suffering much more the effects of the pandemia because their lack of access to services and in a much wider perspective, to education and welfare. We will show that, during the COVID crisis, despite lockdown measures, various actions at the formal political level (from the Italian Deaf Association) and at the informal level (from the members of the community) promoted sign language and the Deaf community within the hearing majority. In particular, we will analyse how social networks were exploited at the grassroot level in order to promote social cohesion and share information about the coronavirus emergency and how the Deaf community shaped the interpreting services on the public media. The role of social networks, however, has gone far beyond the emergency as it has allowed deaf people to create a new virtual space where it was possible to discuss the appropriateness of various linguistic choices related to the COVID lexicon and to argue about the various interpreting services. Furthermore, in such emergency, the interpreting services were shaped following the needs expressed by the Deaf community with the results of an increased visibility of Italian sign language (LIS) and empowerment of the community. Materials spontaneously produced by members of the Deaf Italian community (conferences, debates, fairy tales, and entertainment games) were selected, as well as materials produced by LIS interpreters committed to guaranteeing access to information. By highlighting the strategies that a minority group put in place to deal with the COVID-19 emergency, we can better understand the peculiarities of that community, creating a bridge between worlds that often travel in parallel for respecting the peculiarities of each other (deaf and hearing communities).

Sign Language Skills Assessed Through a Sentence Reproduction Task

The aim of this study is to analyze Italian Sign Language (LIS) linguistic skills in two groups of deaf signing children at different ages, and to compare their skills with those of a group of deaf signing adults. For this purpose, we developed a new Sentence Reproduction Task (SRT) for Italian Sign Language (LIS-SRT), which we administered to 33 participants. Participants' scores and type of errors were analyzed to investigate similarities and differences related to both chronological age and age of LIS acquisition. Results showed that signs tended to be omitted more frequently by the younger children than both the older children and adults and that non-manual components produced simultaneously with manual components appear to be the most difficult linguistic elements to be acquired and mastered. Our results are compared to those of previous studies using SRTs for other signed languages.

Developmental evidence for continuity from action to gesture to sign/word

What is linguistic communication and what is it not? Even if we often convey meanings through visible bodily actions, these are rarely considered part of human language. However, co-verbal gestures have compositional structure and semantic significance, while highly iconic structures are essential in sign languages. This paper offers a review of major studies conducted in our lab on the continuity from actions to gestures to words/signs in development. After a brief introduction, we show how gestures may bridge the gap between actions and words and how this interrelationship extends beyond early childhood and across cultures. We stress the role of sign language and multimodal communication in the study of language as a form of action and present recent research on motoric aspects of human communication. Studying the visible actions of speakers and signers leads to a revision of the traditional dichotomy between linguistic and enacted, and to the development of a new approach to embodied language.

Gesture and Symbolic Representation in Italian and English-Speaking Canadian 2-Year-Olds

Analyses of elicited pantomime, primarily of English-speaking children, show that preschool-aged children are more likely to symbolically represent an object with gestures depicting an object's form rather than its function. In contrast, anecdotal reports of spontaneous gesture production in younger children suggest that children use multiple representational techniques. This study examined the spontaneous gestures of sixty-four 2-year-old Italian children and English-speaking Canadian children, primarily from middle-class Caucasian families. The Italian children produced twice as many gestures as Canadian children in a picture-naming task but produced a similar range of representational techniques. Two-year-olds were equally likely to produce gestures depicting function as form. These data suggest young children's communicative skills are supported by a symbolic capacity that reflects contextual communicative demands.

The body and the fading away of abstract concepts and words: a sign language analysis

One of the most important challenges for embodied and grounded theories of cognition concerns the representation of abstract concepts, such as “freedom.” Many embodied theories of abstract concepts have been proposed. Some proposals stress the similarities between concrete and abstract concepts showing that they are both grounded in perception and action system while other emphasize their difference favoring a multiple representation view. An influential view proposes that abstract concepts are mapped to concrete ones through metaphors. Furthermore, some theories underline the fact that abstract concepts are grounded in specific contents, as situations, introspective states, emotions. These approaches are not necessarily mutually exclusive, since it is possible that they can account for different subsets of abstract concepts and words. One novel and fruitful way to understand the way in which abstract concepts are represented is to analyze how sign languages encode concepts into signs. In the present paper we will discuss these theoretical issues mostly relying on examples taken from Italian Sign Language (LIS, Lingua dei Segni Italiana), the visual-gestural language used within the Italian Deaf community. We will verify whether and to what extent LIS signs provide evidence favoring the different theories of abstract concepts. In analyzing signs we will distinguish between direct forms of involvement of the body and forms in which concepts are grounded differently, for example relying on linguistic experience. In dealing with the LIS evidence, we will consider the possibility that different abstract concepts are represented using different levels of embodiment. The collected evidence will help us to discuss whether a unitary embodied theory of abstract concepts is possible or whether the different theoretical proposals can account for different aspects of their representation.

Sign vocabulary in deaf toddlers exposed to sign language since birth

Lexical comprehension and production is directly evaluated for the first time in deaf signing children below the age of 3 years. A Picture Naming Task was administered to 8 deaf signing toddlers (aged 2-3 years) who were exposed to Sign Language since birth. Results were compared with data of hearing speaking controls. In both deaf and hearing children, comprehension was significantly higher than production. The deaf group provided a significantly lower number of correct responses in production than did the hearing controls, whereas in comprehension, the 2 groups did not differ. Difficulty and ease of items in comprehension and production was similar for signing deaf children and hearing speaking children, showing that, despite size differences, semantic development followed similar paths. For signing children, predicates production appears easier than nominals production compared with hearing children acquiring spoken language. Findings take into account differences in input modalities and language structures.

A developmental study on children's capacity to ascribe goals and intentions to others

The capacity to ascribe goals and intentions to others is a fundamental step in child cognitive development. The aim of the present study was to assess the age at which these capabilities are acquired in typically developing children. Two experiments were carried out. In the first experiment, 4 groups of children (age range = 3 years 2 months-7 years 11 months) were shown pictures representing hand-object interactions and asked what the individual was doing (what task) and why (why task). In the why task, observed handgrip could be either congruent with the most typical action performed with that object (e.g., to drink in the case of a mug) or corresponding to the act of putting away the object. In the second experiment, children saw pictures showing a handgrip either within a context suggesting the most typical use of the object or its being put away. Results showed that by 3-4 years, children are able to state the goal relatedness of an observed motor act (what understanding), whereas the ability to report the intention underlying it (why understanding) is a later and gradual acquisition, reaching a high performance by 6-7 years. These results, besides their intrinsic value, provide an important baseline for comparisons with studies on developmental disorders, also highlighting the relevance of distinguishing what and why understanding.

Deaf children attending different school environments: sign language abilities and theory of mind

The present study examined whether full access to sign language as a medium for instruction could influence performance in Theory of Mind (ToM) tasks. Three groups of Italian participants (age range: 6-14 years) participated in the study: Two groups of deaf signing children and one group of hearing-speaking children. The two groups of deaf children differed only in their school environment: One group attended a school with a teaching assistant (TA; Sign Language is offered only by the TA to a single deaf child), and the other group attended a bilingual program (Italian Sign Language and Italian). Linguistic abilities and understanding of false belief were assessed using similar materials and procedures in spoken Italian with hearing children and in Italian Sign Language with deaf children. Deaf children attending the bilingual school performed significantly better than deaf children attending school with the TA in tasks assessing lexical comprehension and ToM, whereas the performance of hearing children was in between that of the two deaf groups. As for lexical production, deaf children attending the bilingual school performed significantly better than the two other groups. No significant differences were found between early and late signers or between children with deaf and hearing parents.

Motoric characteristics of representational gestures produced by young children in a naming task

This study explores the form of representational gestures produced by forty-five hearing children (age range 2 ; 0-3 ; 1) asked to label pictures in words. Five pictures depicting objects and five pictures depicting actions which elicited more representational gestures were chosen for more detailed analysis. The range of gestures produced for each item varied from 3 to 27 for a total of 128 gestures. Gestures have been analyzed with the same parameters used to describe signs produced by deaf children: handshape, location and movement. Results show that gestures for a given picture exhibit similarities in many of the parameters across children. Some motor characteristics found in the production of hearing toddlers' gestures are similar to those described for early signs. Implications of this similarity between gestural and signed linguistic representations in young children are discussed.

Learning to talk in a gesture-rich world: Early communication in Italian vs. American children

Italian children are immersed in a gesture-rich culture. Given the large gesture repertoire of Italian adults, young Italian children might be expected to develop a larger inventory of gestures than American children. If so, do these gestures impact the course of language learning? We examined gesture and speech production in Italian and US children between the onset of first words and the onset of two-word combinations. We found differences in the size of the gesture repertoires produced by the Italian vs. the American children, differences that were inversely related to the size of the children's spoken vocabularies. Despite these differences in gesture vocabulary, in both cultures we found that gesture + speech combinations reliably predicted the onset of two-word combinations, underscoring the robustness of gesture as a harbinger of linguistic development.

Spoken and gestural production in a naming task by young children with Down syndrome

Lexical production in children with Down syndrome (DS) was investigated by examining spoken naming accuracy and the use of spontaneous gestures in a picture naming task. Fifteen children with DS (range 3.8-8.3 years) were compared to typically developing children (TD), matched for chronological age and developmental age (range 2.6-4.3 years). Relative to TD children, children with DS were less accurate in speech (producing a greater number of unintelligible answers), yet they produced more gestures overall and of these a significantly higher percentage of iconic gestures. Furthermore, the iconic gestures produced by children with DS accompanied by incorrect or no speech often expressed a concept similar to that of the target word, suggesting deeper conceptual knowledge relative to that expressed only in speech.

Laterality in Persons with Intellectual Disability. I—Do Patients with Trisomy 21 and Williams–Beuren Syndrome Differ from Typically Developing Persons?

Persons with trisomy 21 (T21) and Williams-Beuren syndrome (WBS) have different brain abnormalities which may affect manual laterality. We assessed 45 persons with T21 and 34 with WBS (mean age 13) and 81 typically developing children (TD). Manual laterality was assessed with a fifteen-item task administered two times, and Bishop's card-reaching task. We found more left-handers in the T21 group compared to the other two groups. Inconsistent laterality was higher in the two groups with genetic diseases than in the TD group. For Bishop's test, both T21 and WBS participants were less right-oriented than the TD group. They displayed different response patterns in midline crossing when reaching for the cards, but did not display more midline crossing inhibition than the TD group. Is atypical handedness linked to specific genetic syndromes and, more specifically for persons with T21, to the trisomy of some of the genes?

Laterality in persons with intellectual disability II. Hand, foot, ear, and eye laterality in persons with Trisomy 21 and Williams-Beuren syndrome

Laterality (hand, foot, ear, and eye) was assessed in participants with Trisomy 21 (62) and Williams-Beuren syndrome (WBS) (39). Handedness was also assessed in a card reaching task. The comparison group included 184 typically developing persons. Two independent age sub-groups were formed: 7 to 10 years old and 11 to 34 years old. We confirmed previous data: individuals with T21 were more frequently left- or mixed-handed than typically developing persons; individuals with WBS had intermediate scores. The two groups with genetic disorders had less right foot preference. Manual and foot inconsistencies characterized both groups with genetic disorders. Cross hand-foot preference was lower in the typically developing group. Differences in IQ levels did not correlate with differences in laterality scores. Overall laterality profiles were not the same in the two groups with genetic disorders: the greatest differences were observed between typically developing persons and persons with Trisomy 21.

Neuropsychological profile of Italians with Williams syndrome: an example of a dissociation between language and cognition?

Important claims have been made regarding the contrasting profiles of linguistic and cognitive performance observed in two genetically based syndromes, Williams syndrome (WS) and Down syndrome (DS). Earlier studies suggested a double dissociation, with language better preserved than nonverbal cognition in children and adults with WS, and an opposite profile in children and adults with DS. More recent studies show that this initial characterization was too simple, and that qualitatively different patterns of deficit observed within both language and visual-spatial cognition, in both groups. In the present study, large samples of children and adolescents with WS and age-matched DS are compared with typically developing (TD) controls matched to WS in mental age, on receptive and expressive lexical and grammatical abilities, semantic and phonological fluency, digit span and nonverbal visual-spatial span, and on 2 visual-spatial construction tasks. Study 1 confirmed distinct profiles of sparing and impairment for the 2 groups, within as well as between language and nonlinguistic domains, even after IQ variations were controlled. In Study 2 we compared performance of the children, adolescents and young adults with DS and WS included in the first study, divided on the basis of the chronological age of the participants (under 8 years; over 12 years). Although it is important to stress that these are cross-sectional rather than longitudinal data, the results demonstrated that the profile of younger children is different in respect to those of the older children; initial states of the system cannot be inferred by the final state. Possible neural substrates for these profiles and trajectories are discussed.

Lexical production in children with Williams syndrome: spontaneous use of gesture in a naming task

This study investigates lexical organization and lexical retrieval in children with Williams syndrome (WS), by examining both naming accuracy and accompanying use of gestures in a picture-naming task. Ten children with the genetic disorder of Williams syndrome (age range: 9.5-12.9) were compared with 20 typically developing children, 10 matched for chronological age (CA) and 10 for mental-age (MA). Lexical production was measured by administering the Boston Naming test (BNT). Older typically developing children performed significantly better than the other two groups. No differences in accuracy were found between the children with WS and the typically developing children matched for mental-age. The overall distribution of error types displayed by children with WS indicate that the lexical-semantic organization is similar to that of typically developing children. However, compared to controls, the WS group produced more iconic gestures during the task, in patterns that suggest the existence of specific word-finding difficulties in these children. Results are discussed within the framework of recent theories on the role of gesture in speech production.

Early linguistic abilities of Italian children with Williams syndrome

Previous studies of linguistic and memory abilities in Italian-speaking children with Williams syndrome (WS) and Down syndrome (DS)are briefly reviewed. New data on linguistic performance of 6 Italian children with WS between 3 and 6 years of age are presented and compared with data on linguistic performance of 6 children with DS selected from a larger sample and matched for chronological age and vocabulary size and of 6 typically developing (TD) younger children matched for mental age and vocabulary size. The language measures also included a parent report of early phrase structure, a naming test, and a sentence repetition task. Analyses revealed that the 3 groups of children were at the same productive vocabulary level, but showed different patterns in sentence production and repetition. Children with WS produced more complete sentences, similar to TD children at the same vocabulary size, whereas children with DS produced more telegraphic and incomplete sentences. The difference between children with DS and those with WS was more marked on the repetition task, suggesting that phonological short-term memory may play a greater role when sentence production is measured through repetition. In addition, qualitative analysis of errors produced in the repetition test revealed interesting differences among the 3 groups. These results from younger children confirm and extend previous findings with older children and adolescents with WS. They further suggest that the apparently spared linguistic abilities of children with WS could emerge as an artifact of comparisons made to children with DS, whose sentence production competence is more compromised relative to other verbal and nonverbal abilities.

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.

Analysis of reboxetine, a novel antidepressant drug, in pharmaceutical tablets by capillary electrophoresis and derivative spectrophotometry

The recent antidepressant drug reboxetine was quantified in pharmaceutical tablets by derivative spectrophotometry and capillary zone electrophoresis. The feasible sample pretreatment consists of a single extraction with a pH 2.5 phosphate buffer, centrifugation and dilution. For the spectrophotometric assay, the fourth derivative of the absorbance was used which gave satisfactory results in terms of accuracy (mean recovery 99.7%) and precision (mean RSD 3.4%). The electrophoretic experiments were carried out using the shortest effective length of the capillary (8.5 cm) in order to obtain a very rapid separation of reboxetine and dibenzepine used as the internal standard. Using a pH 2.5, 50 mM phosphate buffer as the background electrolyte, each analysis lasted less than 2.5 min. Accuracy (101.3%) and precision (1.5%) were very good.

Drawing abilities in Williams syndrome: a case study

Children with Williams syndrome (WS) have been reported to exhibit an unusual cognitive profile characterized by marked preservation of linguistic abilities and poor visuospatial abilities against a backdrop of generalized mental retardation. Much of the data documenting this profile come from studies of older children and adults with WS. Very few studies have reported findings from the preschool and early school-age period. As a result, little is known about the early development of cognitive processes in children with WS. Capirci, Sabbadini, and Volterra (1996) reported data from a longitudinal case study of early language development in a young child with WS. This article presents the longitudinal profile of visuospatial abilities in this same child. Data on copying and free drawing collected over a period extending from late preschool to early school age are reported. It is clear from these data that this child does indeed exhibit deficits in visuospatial abilities. Her performance clearly improved with age, but deficits persist.

Rapid capillary electrophoretic method for the determination of clozapine and desmethylclozapine in human plasma

A rapid and sensitive high-performance capillary electrophoretic method for the determination of clozapine and its main metabolite desmethylclozapine in human plasma was developed. The separation of the two analytes was carried out in an untreated fused-silica capillary [33 cm (8.5 cm effective length) x 50 microm I.D.] filled with a background electrolyte at pH 2.5 containing beta-cyclodextrin. Baseline separation of clozapine and desmethylclozapine was recorded in less than 3 min. An accurate sample pretreatment by means of solid-phase extraction and subsequent concentration allows for reliable quantitation of clozapine in the plasma of schizophrenic patients under treatment with the drug. The method showed good precision (mean RSD = 4.0%) as well as satisfactory extraction yields (approximately 88%) and a good sensitivity (limit of quantitation = 0.075 microg ml(-1), limit of detection = 0.025 microg ml(-1)).

Comparison of three analytical methods for quality control of clozapine tablets

Three different analytical methods for the quality control of clozapine in commercial formulations were developed and compared: a liquid chromatographic (LC) method with UV detection, a capillary zone electrophoretic (CZE) method, and a linear scan voltammetric (LSV) method. The isocratic LC procedure used a C18 reversed-phase column; the CZE method used an uncoated fused-silica capillary and phosphate buffer containing polyvinylpyrrolidone as the background electrolyte; the LSV method analyzed clozapine solutions with acidic phosphate buffer as the supporting electrolyte. The 3 methods gave similar and satisfactory results, in terms of precision and accuracy. Repeatability and intermediate precision were good (RSD% < 2.2) and accuracy, resulting from recovery studies, was between 98 and 102%. The rapidity of analysis was high for all 3 methods, especially for the LSV.

Development of acute psychotic disorders and HIV-1 infection

OBJECTIVE

To gain more understanding about the relationship between human immunodeficiency virus type 1 (HIV-1) infection and new-onset psychosis, we compared clinical and immunological findings, psychiatric symptoms, global cognitive performance and, when available, computerized tomography (CT) findings between HIV-1-seropositive patients with new-onset psychosis and well-matched nonpsychotic HIV-1-seropositives.

METHODS

Two groups of subjects: HIV-1-seropositives with new-onset psychosis (n = 12) and HIV-1-seropositives without psychosis (n = 15) were recruited through outpatient departments. Organic Delusional Syndrome and Organic Hallucinosis were clinically diagnosed using DSM-III-R diagnostic criteria. Of the baseline participants, twenty-two participated in the two-year follow-up examination.

RESULTS

The prevalence of new-onset psychosis in HIV-1-infected subjects was 3.7 per 100 (95% C.I. = 1.6-5.7). HIV-1-seropositive persons with new-onset psychosis had more frequently a positive past psychiatric history, no antiretroviral therapy, and a lower global cognitive performance than did the nonpsychotic HIV-1-seropositives. CT was positive, showing generalized brain atrophy, in three out of nine patients. Remission of psychotic symptoms was observed only in two HIV-1-seropositive persons with new-onset psychosis. Death occurred in two psychic HIV-1-seropositives with simple loosely held delusions. Autopsy results showed that cortical sulci and ventricle size were graded as with moderate/severe enlargement.

CONCLUSIONS

New-onset psychosis in HIV infected patients could raise considerable problems in deciding whether a presentation is organic or functional. An interaction of the disease or of psychologically "having" the disease with the presence of a psychotic reaction should also be considered. Interestingly, a protective effect of antiretroviral therapy for new-onset psychosis is suggested.

A sensitive high-performance liquid chromatographic method using electrochemical detection for the analysis of olanzapine and desmethylolanzapine in plasma of schizophrenic patients using a new solid-phase extraction procedure

A high-performance liquid chromatographic method with amperometric detection for the analysis of the novel antipsychotic drug olanzapine and its metabolite desmethylolanzapine in human plasma has been developed. The analysis was carried out on a reversed-phase column (C8, 150 x 4.6 mm I.D., 5 microm) using acetonitrile-phosphate buffer, pH 3.8, as the mobile phase. The detection voltage was + 800 mV and the cell and column temperature was 30 degrees C. The flow-rate was 1.2 ml min(-1). Linear responses were obtained between 5 and 150 ng ml(-1), with repeatability <3.3%. A careful pretreatment of the biological samples was implemented by means of solid-phase extraction (SPE) on C8 cartridges. The method requires 500 microl of plasma for one complete analysis. Absolute recovery exceeded 97% for both olanzapine and desmethylolanzapine, and the detection limit was 1 ng ml(-1) for both analytes. Repeatability, intermediate precision and accuracy were satisfactory. This sensitive and selective method has been successfully applied to therapeutic drug monitoring in schizophrenic patients treated with Zyprexa tablets.

Serum NGF levels in children and adolescents with either Williams syndrome or Down syndrome

The neurotrophin nerve growth factor (NGF) is a major regulator of peripheral and central nervous system development. Serum NGF was measured in normally developing control children (n=26) and in individuals affected by congenital syndromes associated with learning disability: either Williams syndrome (WS; n=12) or Down syndrome (DS; n=21). Participants were assessed at three distinct developmental stages: early childhood (2 to 6 years), childhood (8 to 12 years), and adolescence (14 to 20 years). A sample was taken only once from each individual. Serum NGF levels were markedly higher in participants with WS, than DS and control participants. In addition, different developmental profiles emerged in the three groups: while in normally developing individuals NGF levels were higher in early childhood than later on, children with WS showed constantly elevated NGF levels. When compared to control participants, those with DS showed lower NGF levels only during early childhood. Neuropsychological assessment confirmed previously reported differences among the three groups in the development of linguistic/cognitive abilities. Some features of individuals with WS, such as hyperacusis and hypertension, could be related to high-circulating NGF levels.

A rapid LC method for the identification and determination of CNS drugs in pharmaceutical formulations

Antidepressant, neuroleptic and antiepileptic drugs were identified and determined in pharmaceutical formulations (tablets, capsules and oral solutions) by a rapid high-performance liquid chromatography method. The sample pretreatment consisted of a one-step extraction, filtration and dilution. The chromatographic conditions were: reversed-phase C8 column (150 x 4.6 mm i.d., 5 microm); acetonitrile-tetramethylammonium perchlorate aqueous solution (pH 2.8; 12.6 mM) (45:55, v/v) as the mobile phase; detection wavelength, 230 nm. Calibration curves were linear in the 100-1000 ng ml(-1) range for all tested drugs except for phenobarbital. The repeatability (or intra-day precision), expressed by the relative standard deviation, was better than 2.0%. The accuracy, resulting from recovery studies, was between 98.1 and 101.3%. The amount of drug found agreed with the declared content within the limits specified by United States Pharmacopeia and British Pharmacopeia.

[Williams syndrome]

Williams syndrome (WS) is a rare (2-5/100,000) genetic human disorder characterised by a typical facies and mental retardation with a deficit in the visuospatial cognitive function and a relative preservation of linguistic abilities in general, and spoken language in particular. This syndrome also includes morphological anomalies, metabolic functional impairments, and likely deficits in the pattern of brain ontogenesis. The genetic basis of WS, recently identified, are presented. A cognitive profile of the WS individuals is defined and compared to Down syndrome (DS) and autism cognitive profiles. Neuroanatomical features of WS, including a reduction in brain volume, preservation of cerebellum and frontal lobes, and a reduction of posterior cortical systems, are described. The possible role of NGF (nerve growth factor)--a neurotrophin involved in the development of brain cholinergic systems and the associated behavioural functions--in the aetiology of the typical mental retardation of WS patients, is critically discussed. Future research avenues, including the identification of potential neurobiological markers in order to precociously diagnose this syndrome, are reviewed.

Visuo-spatial and linguistic abilities in a twin with Williams syndrome

The present study reports a case of dizygotic twins, one boy with Williams syndrome (WS) and one typically developing girl, and compares their neuropsychological profiles. The goal of the present authors was to verify whether the child with WS displayed a cognitive profile which is unique to the syndrome. Several tests designed to assess visuo-perceptual, visuo-motor, linguistic and memory abilities were administered to both children when they were 10.9 years old. Compared to his sister, the boy with WS displayed a homogeneous developmental delay in both non-verbal and verbal abilities. He achieved a level of performance similar to his sister only in facial recognition, phonological word fluency and memory for phonologically similar words. Furthermore, despite the overall delayed performance of the boy, both the twins displayed a cognitive profile characterized by strength in lexical comprehension and relative weakness in visuo-motor abilities.