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Biomedical subjects

L Girelli

Publications and source records attributed to L Girelli.

At least 19 recordsLinked to original sources
PubMed2005

Mathematical skills in Prader-Willi Syndrome.

OBJECTIVES: This paper investigates mathematical skills in Prader-Willi Syndrome (PWS), a pathological condition because of congenital alterations of chromosome pair 15. The following questions were addressed: (1) Are mathematical skills in PWS relatively more impaired with respect to other cognitive functions (as has been repeatedly but anecdotally reported)?; and (2) What is the nature of the mathematical impairment? METHODS: The first study employed the Wechsler Adult Intelligence Scale (WAIS) and an extensive battery of cognitive tasks for which norms are known. Both batteries include a mathematical section. The second study used a theoretically motivated series of mathematical tasks specifically designed to individually assess the different cognitive components underlying mathematical skills. RESULTS: Mathematical skills were found to be the most impaired cognitive abilities together with short-term memory capacity. No specific mathematical domain was seen to be unaffected in PWS participants. The clearest deficits observed concern 'syntactic' processes in number transcoding, multiplication, number facts retrieval and calculation procedures. CONCLUSION: Failure of mathematical skills is the most distinctive feature in the cognitive profile of PWS. However, to determine whether this is indeed a specific pattern of performance related to PWS, results must be compared with those obtained with patients manifesting other genetic disorders.

Adolescent↗
PubMed2003

Number processing and calculation--normative data from healthy adults.

Despite the high incidence of numerical deficits in neurological patients, little attention has been paid to the development of diagnostic tools. In fact, most of the published reports on acquired numerical disorders, whether single case or group studies, do not refer to standardised measures of performance providing little, if any, control data specifically collected for the examination. In this study we present data of 282 healthy controls of different age groups and educational levels in a new battery of Number Processing and Calculation (NPC). The NPC battery includes a total of 35 tasks, assessing different counting abilities, various aspects of number comprehension (such as parity and magnitude judgements), numerical transcoding, calculation, arithmetic reasoning and conceptual knowledge. Special attention is paid to the assessment of different calculation abilities, including simple fact retrieval, rule based processing, mental calculation and written calculation in all four operations. Moreover, text problem solving is assessed as well as the understanding of arithmetic principles. Thus, the NPC battery differs from the EC 301 battery proposed by Deloche et al., 1994 (Dellatolas, Deloche, Basso, & Claros-Salinas, 2001) and allows a more fine grained diagnosis which is relevant for planning targeted interventions. The battery is easy to administer and does not require special materials or equipment.

Adolescent↗
PubMed2002

Functional evaluations in the monitoring of the river ecosystem processes: the Adige River as a case stu.

A model of analysis and environmental evaluation was applied to 11 stretches of the Adige River, where an innovative procedure was carried out to interpret ecological results. Within each stretch, the most suitable methods were used to assess the quality and processes of flood plains, banks, water column, bed, and interstitial environment. Indices were applied to evaluate the wild state and ecological quality of the banks (wild state index, buffer strip index) and the landscape quality of wide areas of the fluvial corridor (environmental landscape index). The biotic components (i.e., macrozoobenthos, phytoplankton and zooplankton, interstitial hyporheic fauna, vegetation in the riparian areas) were analysed by both quantitative and functional methods (as productivity, litter--processing and colonisation). The results achieved were then translated into five classes of functional evaluation. These qualitative assessments have thus preserved a high level of precision and sensitivity in quantifying both the quality of the environmental conditions and the integrity of the ecosystem processes. Read together with urban planning data, they indicate what actions are needed to restore and rehabilitate the Adige River corridor.

Animals↗
PubMed2001

Storage and retrieval of addition facts: the role of number comparison.

It is proposed that arithmetical facts are organized in memory in terms of a principle that is unique to numbers--the cardinal magnitudes of the addends. This implies that sums such as 4 + 2 and 2 + 4 are represented, and searched for, in terms of the maximum and minimum addends. This in turn implies that a critical stage in solving an addition problem is deciding which addend is the larger. The COMP model of addition fact retrieval incorporates a comparison stage, as well as a retrieval stage and a pronunciation stage. Three tasks, using the same subjects, were designed to assess the contribution of these three stages to retrieving the answers to single-digit addition problems. Task 3 was the addition task, which examined whether reaction times (RTs) were explained by the model; Task 1 was a number naming task to assess the contribution of the pronunciation stage; Task 2 was a magnitude comparison task to assess the contribution, if any, of the comparison stage. A regression equation that included just expressions of these three stages was found to account for 71% of the variance. It is argued that the COMP model fits not only the adult RT data better than do alternatives, but also the evidence from development of additional skills.

Adult↗
PubMed2000

The development of automaticity in accessing number magnitude.

This study traces developmental changes in automatic and intentional processing of Arabic numerals using a numerical-Stroop paradigm. In Study 1, university students compared the numerical or physical size of Arabic numerals varying along both dimensions. In Study 2, first graders (mean age = 6 years 6 months), third graders (mean age = 8 years 4 months), and fifth graders (mean age = 10 years 3 months) were tested to examine developmental changes in numerical and physical comparisons. In the numerical comparison task, a size congruity effect was found at all ages (i.e., relative to a neutral control, congruent physical sizes facilitated, and incongruent sizes interfered with, the numerical comparison). The pattern of facilitation and interference, however, was modulated by age. In the physical comparison task, the incongruity between physical and numerical size affected only older children and adults. These findings strongly suggest that the automatization in number processing is achieved gradually as numerical skills progress.

Adult↗
PubMed1999

Arithmetic reasoning and implicit memory: a neuropsychological study on amnesia.

The present study investigates implicit memory and arithmetic reasoning in a group of severely amnesic patients. Priming effects have been observed in the retrieval of arithmetic facts in amnesic patients (Delazer, Ewen and Benke, 1997), but no studies have so far investigated the effect of previous experience in a pure reasoning task. Findings indicate that answering to a first numerical series (e.g, 1 3 5 7, answer "9") facilitates answering to a second numerical series (2 4 6 8, answer "10") including different numbers but sharing the same underlying algorithm (+ 2). Within the model of Langdon and Warrington (1997) priming effects are attributed to the stage of abstract formula generation.

Adult↗
PubMed1999

Numerical skills and aphasia.

The aim of this study was to investigate numerical difficulties in 50 patients with left hemispheric lesions. Aphasic patients were grouped according to their type of aphasia diagnosed by the Aachener Aphasia Test. The overall error rate in various transcoding and calculation tasks was clearly correlated with the severity of the language deficit, global aphasics being the most impaired patients. Broca's and Wernicke's aphasics scored similarly at the quantitative level, and amnesic aphasics were less impaired. Interestingly, qualitative analysis of the errors indicated that each group presented with specific difficulties, partially reflecting the nature of the language problems. In simple calculation, multiplication was found to be the most impaired operation, in particular in Broca's aphasics. This result supports the hypothesis that the retrieval of multiplication facts is preferentially mediated by verbal processing. Calculation procedures were mainly impaired in Wernicke's and global aphasics.

Adult↗
PubMed1998

Gender differences in visuo-spatial processing: the importance of distinguishing between passive storage and active manipulation.

The study here reported investigates the hypothesis that gender differences in visuo-spatial abilities are mainly confined to active processing tasks. Male and female participants were required to perform passive tasks involving the recall of previously memorized positions within matrices of different sizes, as well as active tasks in which they had to mentally follow a pathway in the same matrices. The results confirmed that male superiority became evident as the active processing requirements increased while only marginal gender difference was reported in passive tasks. To strengthen the specific role of the active-passive distinction in identifying gender differences, confounding factors such as type of material and use of verbal strategies were ruled out. These findings, in line with a number of studies on individual differences, high-light the importance of addressing visuo-spatial ability as a multicomponential cognitive function which entails different type of visuo-spatial processing or mechanisms (i.e., active processing and passive storage of information) rather than as a unitary concept.

Adolescent↗
PubMed1997

A deficit for arithmetical procedures: lack of knowledge or lack of monitoring?

A patient is described with a specific deficit for arithmetical procedures. Unlike in previously described cases, where the observed problems could be attributed to the systematic application of disturbed algorithms, this patient's difficulty seems to stem from an inability to monitor the sequence of operations that calculation procedures specify. Criteria are provided for distinguishing impairments in written calculation due to the application of defective knowledge of the procedures from those determined by lack of monitoring. The role of monitoring and control processes in different calculation components is also discussed.

Animals↗
PubMed1996

Subtraction bugs in an acalculic patient.

We report a patient, MT, who presented a specific, though not isolated, deficit in written calculation. Despite a preserved knowledge of simple arithmetic - single-digit addition and subtraction - he failed systematically in multi-digit subtraction. The nature of errors was consistent across problems and reflected the application of a disturbed underlying algorithm. Moreover, the pattern of error observed mimies a very common finding in developmental studies on arithmetical procedure acquisition (Fuson, 1990, 1992, Young and O'Shea, 1981; VanLehn, 1986, 1990). The data suggest that, within calculation skills, syntax may exist as a system of stable, but inappropriate, rules which are independent of any underlying conceptual knowledge.

Aphasia↗
PubMed1996

The representation of arithmetical facts: evidence from two rehabilitation studies.

We report the improvement following rehabilitation of two patients with a selective deficit on multiplication facts. The remediation experiments were conducted in specific designs to test a series of hypotheses about both the process of reacquisition and organisation of arithmetical facts in memory. The results show a significant and stable recovery and the pattern of reacquisition reflects the different strategy used by the patients to relearn the multiplication facts. Quantitative and qualitative changes in error patterns in the course of remediation reveal the underlying (re)organization of the memory network representing multiplication facts.

Adult↗
PubMed1977

[Application of cytologic vaginal test at the end of pregnancy (author's transl)].

The AA. reviewed the clinical course and the vaginal smear of 146 pregnant women (supposed at term or near term) handled during 1974 and 1975 in the Town Hospital of Cremona. They looked for correlation between the first one and what was inferred form the second one: in order to assess if the vaginal smear during late pregnancy is practically useful in predicting the time of delivery or--at least--the maturation level of the foetus. After reviewing their own results and after considering the results of some other writer, they conclude that the vaginal smear in late pregnancy is scarcely useful because it yields only generical signs liable to broad interpretation.

Female↗
PubMedDate not supplied

Number-Stroop performance in normal aging and Alzheimer's-type dementia.

The number-Stroop paradigm was used to investigate changes in the inhibitory system and in numerical processing in healthy elderly and individuals with dementia of Alzheimer's type (DAT). The size-congruity effect (i.e., relative to neutral trials, incongruent pairs interfere and/or congruent pairs facilitate either numerical or physical comparison) was found in all groups, though the pattern of interference and facilitation varied across them. Overall, the selective attention breakdown was reflected by the increase in interference shown by the older group and the DAT group. On the other hand, the observation of a standard laterality effect andof automatic numerical processing in all groups suggests that access and retrieval of numerical information is relatively resistant to cognitive deterioration.

Adolescent↗
PubMedDate not supplied

Letter and number writing in agraphia: a single-case study.

The gradual recovery of writing abilities of a patient whose processing of Arabic numerals and alphabetic script evolved differently over time is reported. Writing of multidigit numerals was achieved when writing of letters was nil. However, despite an initial advantage for numbers, the final examination disclosed fluent and correct writing of letters and words together with specific syntactic difficulties in complex Arabic numerals. The differential improvement for Arabic and alphabetic stimuli is partly explained in terms of different processing requirements rather than in terms of script-specific mechanisms only.

Aged↗
PubMedDate not supplied

Priming arithmetic reasoning in an amnesic patient.

The present study elucidates the role of implicit memory in problem solving by evaluating priming effects in a severely amnesic patient. An arithmetic series completion task was adopted to investigate the effects of lags, of items difficulty, as well as the influence of different distractor tasks on priming numerical reasoning. The results indicated that the priming effect was maximized in difficult trials and disappeared after long lags. On the other hand, the facilitation effect was not modulated by the nature of the distractor tasks. Critically, the experimental design controlled for peripheral facilitation of visual input and verbal output processes and a recognition task indicated that the effect may not be attributed to explicit memory. Thus, the facilitation must be located to a more central stage, possibly at the stage in which the abstract formula of the underlying algorithm are generated (Langdon & Warrington, 1997).

Adult↗