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Biomedical subjects

D Brizzolara

Publications and source records attributed to D Brizzolara.

12 recordsLinked to original sources
PubMed2001

del (9p) syndrome: proposed behavior phenotype.

Over recent years interest in the study of behavior phenotypes has gained increasing momentum. We present three white female patients, age respectively 9 years 9 months, 14 years 6 months and 18 years at the time of the last observation, seen because of developmental delay/mental retardation, seizures and learning disabilities. Cytogenetic analysis showed a de novo deletion of the short arm of chromosome 9 in all three, with the breakpoint being located at band 9p22. Although several studies have described the somatic phenotype, analytical evaluation of verbal and non-verbal cognitive functions are lacking. Our patients received a detailed neuropsychological and linguistic evaluation that showed a particular behavior profile, in the context of mental retardation of variable degree. On selective tests there was a marked deficit in visuo-praxic and visuo-spatial skills associated with memory disturbance. Visuo-motor integration abilities [VMI; Beery, 1997] and visuo-perceptual and visuo-spatial abilities [Benton line orientation test, 1992] seemed particularly impaired, both in relation to verbal mental age (vocabulary and grammatical production/comprehension) and to some non-verbal competencies [Benton face recognition test, 1992]. The profile shows advanced performances in face recognition. In addition, there is also a dissociation between verbal and visuo-spatial short term memory. This behavior phenotype is similar to that of Williams syndrome (WS) individuals. Our patients also showed some unusual within-domain dissociations regarding linguistic abilities. To better demonstrate similarities and differences between the behavior phenotypes of the del (9p22) syndrome and WS, we studied three IQ-gender-matched WS subjects. The comparison between the cognitive phenotypes of the two syndromes shows similarities in neuropsychological pattern. We hypothesize that there is a gene within the 9p22 region responsible for the neuropsychological profile described here.

Adolescent↗
PubMed1999

"Developmental dysmnesia": a case report.

We report a 9-year-old girl who presented from an early age a severe and specific verbal memory disorder, in the absence of a definite etiology. The results of an extensive neuropsychological assessment showed a dissociation between normal visuo-spatial memory abilities and a marked short-term and long-term verbal memory impairment. We argue that our case is affected by "developmental dysmnesia", a condition so far described in two cases only (De Renzi and Lucchelli, 1990, and Temple, 1997). The disorder affected episodic as well as semantic verbal memory. The long term effects on learning and cognition of a memory deficit occurring early in childhood are discussed.

Child↗
PubMed1998

Visual information processing in infants with focal brain lesions.

Visual information processing for faces were tested by means of the Fagan test of infant intelligence (FTII) in six infants of approximately 12 months of age affected by congenital unilateral brain lesions. Magnetic resonance imaging (MRI) was used to determine the side and size of the lesions. In addition to the FTII, all infants were submitted to a psychometric evaluation using the Griffiths scales. Visual acuity, visual field, and ocular motility were also assessed. Three infants showed damage in the left hemisphere and three in the right. The severity of the lesions, as revealed by MRI scan, was similar in the two groups. All infants except one had normal or borderline cognitive scores on the Griffiths scales. Conversely, four infants showed abnormal results on the FTII, which were not associated with the severity of the lesions, psychometric scores, or the presence of visual deficits. A preference for stimuli presented on the left side of the screen was found, independent of the side of the lesions. This effect was stronger for novel stimuli. The results of this study confirm the importance of early assessment of neuropsychological functions in infants with focal brain lesions.

Cerebral Hemorrhage↗
PubMed1996

Short-term memory in children with Williams syndrome: a reduced contribution of lexical--semantic knowledge to word span.

Williams syndrome (WS) is a genetic syndrome of abnormal neurodevelopment, characterised by a specific linguistic pattern. Comparing performances of WS subjects with those of normal children in a word span task, we found that WS subjects revealed normal phonological similarity and length effects but a reduced frequency effect. Our results suggest comparable phonological encoding mechanisms in WS and normal controls and, at the same time, it provides evidence for an impaired access to lexical-semantic knowledge in WS subjects. This dissociation fits well with the particular pattern of linguistic abilities of these subjects.

Child↗
PubMed1996

Memory abilities in children with Williams syndrome.

Williams syndrome (WS) is a rare genetic condition characterised by intellectual disability, typical facial dysmorphology and several medical anomalies. A specific neuropsychological profile with a dissociation between language (relatively preserved) and visuo-spatial abilities (more seriously impaired) has been hypothesised in these children. Memory abilities of these patients have not been adequately investigated, although they may substantially contribute to better understanding their neuropsychological profile. The present study aimed at investigating verbal and spatial memory in patients with WS (N = 16). Their performance was compared with that of normally developing children on tasks of verbal and spatial span and immediate and delayed recall of verbal and visuo-perceptual materials. Memory abilities of WS children appear to be characterised by defective visuo-spatial memory, both in the short-term and long-term domain, and a dissociation between normal short- but deficient long-term verbal learning. Results are interpreted by supporting the thesis that intellectual disability reflects the defective functioning of a complex system in which some cognitive competencies may be disrupted more than others (Detterman, 1987; Vicari, Albertini and Caltagirone, 1992).

Child↗
PubMed1994

Is interhemispheric transfer time related to age? A developmental study.

In simple visuomotor reaction time tasks, the difference between reaction time (RT) in the uncrossed hand/hemifield condition from RT in the crossed hand/hemifield, known as CUD (crossed-uncrossed difference), has been interpreted as reflecting interhemispheric transmission time (IHTT). Several studies in normal adults have found a CUD of a few milliseconds (3-4), while an abnormally long CUD has been reported in patients who underwent a surgical section of the corpus callosum or in congenital acallosal subjects. The corpus callosum, which is the most important structure for interhemispheric transfer of information, completes its myelination approximately by age ten. It has been hypothesized that the functional maturity of the corpus callosum coincides with the termination of the myelination cycle. No developmental study has focused on the development of IHTT, in relation to callosal maturation. The purpose of our study has been to investigate the development of interhemispheric transfer of visuomotor information in children aged seven to eleven, using a simple RT task with lateralized visual stimuli. The results indicate an age-related decrease of CUD, which we interpret as reflecting the maturation of the corpus callosum during childhood years.

Cerebral Cortex↗
PubMed1990

Neuropsychological assessment in schoolchildren from an area of moderate iodine deficiency.

Neuropsychological assessment was carried out in schoolchildren from a montane area of Eastern Tuscany (Tiberina Valley). This area was found to be moderately iodine deficient (mean urinary iodine excretion: 39 micrograms/g creatinine), with a cumulative goiter prevalence of 51.9% in schoolchildren aged 6-14 yr (goiter prevalence in the control iodine-sufficient area: 5.6%). No significant differences in serum TT4, TT3, FT4I, TSH levels between the endemic and control areas were found, whereas serum thyroglobulin values were significantly higher in the iodine-deficient area (61 +/- 8 vs 17 +/- 1 ng/ml, p less than 0.01). No differences were found as to the height, body weight and pubertal development in the two areas. Neuropsychological assessment, performed in a representative sample of 50 schoolchildren from the endemic area and 50 schoolchildren from the control area, matched for age, sex and socioeconomical conditions, failed to show major differences between the two groups in the global neuropsychological performance and cognitive levels. However, minor but significant differences were noted in the information vocabulary and coding subtests, at least in children aged 8. Although familial cultural influences might play a role, it would appear that some marginal impairment, with particular regard to motor-perceptual functions, be present in areas of moderate iodine deficiency.

Adolescent↗
PubMed1982

Functional cerebral lateralisation; dichotomy or plurality?

Cartoon faces were presented tachistoscopically in the right and left visual fields, and required to be matched to a previously memorised target face. The three different stimuli differed from the target either on only one, or on all three features (eyes, nose, mouth). Reaction times varied considerably across the individual different responses in both conditions. In the first condition field differences consistently favoured the right field; in the second, two favoured the left and the third the right. In both conditions same responses were faster than at least one different response class. Several interpretations in terms of the distinction between "analytic" and "holistic" processes were entertained. Such processes themselves remain somewhat obscure, but there is nothing in the data to suggest that the two cerebral hemispheres might not be essentially ambivalent in their predilections for the two kinds of processing. In which case future research might profitably focus on the emerging plurality of experimental factors governing this cognitive ambivalence, rather than on the simple physical dichotomy.

Adult↗
PubMed1982

Tactile discrimination of direction of lines in relation to hemispheric specialization.

The role of the right hemisphere in a task of haptic discrimination of line orientation was studied in 16 children aged 7.6 and 16 adults aged 25 yr. The exploratory movements were limited to hand and wrist, since it has been shown that distal movements are mediated by the contralateral hemisphere. A comparison of the performance of the two hands shows a clear superiority of the left hand and inferred right hemisphere in both children and adults. An special emphasis in the discussion is given to the role of the experimental procedure in enhancing the effect of the hemispheric functional asymmetries.

Adult↗