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Biomedical subjects

C Semenza

Publications and source records attributed to C Semenza.

At least 19 recordsLinked to original sources
PubMed2006

Decision-making in obesity: a study using the Gambling Task.

The present study addresses the issue of whether a "decision-making disorder" could account for the behavioral problems of severely obese patients (BMI score >34) who are not classified by traditional psychiatric Eating Disorder tests. The neuropsychological test employed, the Gambling Task (GT), is not directly related to the food domain, but it is sensitive to failure in making long-term advantageous choices. A comparison was made of 20 obese subjects (OS) and 20 normal-weight subjects (NWS) matched in age, education and IQ. The subjects' personalities and food behavior were assessed from psychological questionnaires, and then the Gambling Task was administered. The number of "good" choices made by the two groups during GT performance differed significantly, and the OS did not learn to maximize advantageous choices like the NWS did. OS behavior could be consistent with a prefrontal cortex defect that implies difficulties in inhibition of excessive food intake.

Adult↗
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

Anomia for people names in DAT--evidence for semantic and post-semantic impairments.

Proper name anomia is a frequent finding among patients in the early stages of Alzheimer's disease. The present study investigates naming of famous persons in a group of DAT patients, a group of persons with mild cognitive impairment (MCI) and healthy controls. The study is aimed at distinguishing the relative contributions of semantic and post-semantic factors to difficulties in proper name retrieval. As shown by a significantly lower score in answering semantic questions, DAT patients retrieve less biographical knowledge related to famous persons than healthy elderly subjects and persons with mild cognitive impairment. This finding is in line with the frequent observation of semantic deficits in early and moderate DAT. The high number of Tip-of-the-Tongue (TOT) answers in DAT found in relation to few spontaneously named items shows that post-semantic deficits are as important as semantic deficits in determining anomia for people names in DAT. Moreover, DAT patients were less sensitive to phonological cueing than healthy persons or persons with mild cognitive impairment. These findings suggest that proper name anomia in DAT is not only due to semantic deficits, but also to problems in accessing the phonological representation, as well as to a degradation of phonological representations. Thus, naming deficits in DAT differ not only quantitatively, but also qualitatively from the difficulties of healthy elderly persons. No significant differences were found between persons with mild cognitive impairment and healthy controls in proper name retrieval.

Aged↗
PubMed2003

Proper names in patients with early Alzheimer's disease.

The objective of this study was to seek evidence of the particular sensitivity of proper name retrieval and to check the usefulness of proper names as diagnostic material in the early stages of Alzheimer's disease (AD). Whether a generalized naming deficit is an early symptom of AD it is not yet clear. Previous studies suggest that proper names might be the category of names that is indeed more sensitive to AD. Seventy AD patients (subdivided into "very mild", "mild" and "moderate") and 47 control subjects participated in the study. The performances in two short distinct tests requiring proper name retrieval (Naming People on Definition and Naming Faces), one test of common name retrieval, short (MMSE, 3MS) and long (MODA) batteries for the detection of dementia were compared. Proper name retrieval tests were shown to be more sensitive to early AD than any other tests and batteries that failed to distinguish "very mild" AD from controls. These findings suggest that proper name retrieval tasks might be profitably included in diagnostic tools for the early diagnosis of AD.

Aged↗
PubMed2002

Common daily activities in the virtual environment: a preliminary study in parkinsonian patients.

Patients with Parkinson's disease (PD) create behavioral motor strategies by using external cues to facilitate their movements. Virtual reality (VR) could work as an external stimulus in order to explore the motor plans by means of creation of mental images. We tested 2 women with PD aged 68 and 69 years, and 10 normal control subjects. Patients underwent a neuropsychological assessment to evaluate cognitive abilities involved in the tasks required by the VR session. VR environment reproduces common daily activities situations at home, such as eating or using the bathroom. VR describes the alterations of the motor plans in PD by a point of view different from the clinical one, by testing "pure" mental sequences of the execution of a movement, without the interference of motor disability.

Activities of Daily Living↗
PubMed2001

Lexical representation and processing of morphologically complex words: evidence from the reading performance of an Italian agrammatic patient.

The study of patients with acquired language disorders has provided crucial evidence for contemporary theories on mental lexical representation. This is particularly true for the representation of morphologically complex words. In this paper we analyzed the performance of a patient (M.B.) affected by agrammatism and dyslexia. M.B. was required to read aloud simple and morphologically complex words. The patient's pattern of errors was interpreted as the result of a predominant use of the lexical routine (phonological dyslexia). Three reading tasks were developed which allowed us to test M.B.'s ability to read morphologically complex words (reading of regular and irregular plurals; reading of high- and low-frequency singular and plural nouns; reading of evaluative suffixes). Errors were determined by frequency effect rather than by type of suffix (i.e., inflectional or derivational). High-frequency morphologically complex items seemed to meet stored representations, thus avoiding the parsing procedures that are required for less frequent items. These results are in keeping with dual route models of lexical representation of morphologically complex words.

Adult↗
PubMed2001

Naming of musical notes: a selective deficit in one musical clef.

We investigated the ability to perform solfeggio, i.e. oral reading of musical notes in MP, a 65 year-old female professional musician, who, following a left temporoparietal ischemia, showed a complex pattern of amusia. The deficit on which we focused was her inability to read orally the bass (F) clef, often substituting it with the violin (G) clef. This problem could not be attributed to a lack of comprehension. The patient could in fact correctly perform on the piano the same sequences she erroneously read aloud; she was also able to correctly judge whether two strings, one in bass clef and the other in violin clef, represented the same sequence of notes. The problem seems to lie in the inability to retrieve note names keeping into account the clef-rule. It is hypothesized that, in the production of note names, this function requires the identification and application of syntactic-like information, in analogy with what is thought to happen in the retrieval of other words.

Aged↗
PubMed2001

ERP indexes of functional differences in brain activation during proper and common names retrieval.

Functional neuroimaging and neuropsychological findings suggest that memory retrieval of common and proper names is subserved by different neuro-functional systems but little is known about the topographic localization of neural generators. In the present study brain electrical activity was recorded with a high density electrode montage in healthy young volunteers during lexical retrieval upon written definition. ERPs spatio-temporal mapping showed on one side a strong activation of left anterior temporal and left central-frontal areas for proper names, and on the other side a greater involvement of occipital areas for common names retrieval. The specific pattern of bio-electrical activity recorded during proper names retrieval might index the activation of neural circuits for recalling names of high contextual complexity, poor of sensory-motor associations and dependent on precise spatio-temporal coordinates.

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↗
PubMed1999

Repetition priming in simple addition depends on surface form and typicality.

Repetition priming and recognition memory for numbers were measured in four experiments using single-digit addition. Results of the first two experiments indicate that when numbers were presented as number words and dot configurations, preexposure of the same problem in the same notation produced greater reaction-time benefit than did preexposure of the same problem in Arabic-digit notation. In contrast, when numbers were presented as Arabic digits, preexposure of the same problem in Arabic digit, number word, and dot notation produced the same amount of priming. In the third experiment, priming was shown to be greatest, for all three notations, when the task performed on preexposure trials (addition or multiplication) matched the task performed on repetition trials (addition). Results of the fourth experiment, measuring recognition memory, were comparable to the priming results in the sense that memory was superior when notation matched across repetitions if the test involved number words and dot configurations but not Arabic digits. These data are interpreted in terms of models of numerical cognition, and they support the hypothesis that the influence of surface form on repetition priming depends on the typicality of the input for the task.

Attention↗
PubMed1998

The processing of compound words: a study in aphasia.

The naming difficulties of an aphasic patient (MB) are almost exclusively confined to compound words. The paraphasias in response to compounds always reflect the compound structure of the targets. Frequent semantically adequate substitution errors suggest the separate processing of single components at the lemma level. MB's specific difficulties probably arise when two lemmas are defined by one lexical entry, as we suggest for compounds. The compound structure, as well as the positions of the single lemmas within the compound, would be specified before lemmas are accessed. The lack of a positional effect in substitution errors suggests a parallel activation of the two components.

Adult↗
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↗
PubMed1997

The grammatical properties of mass nouns: an aphasia case study.

A patient (F.A.) is described who, as a consequence of brain damage, shows an isolated deficit concerning the use, across a series of tasks, of the grammatical properties of mass/non-countable nouns. Her use of grammar is otherwise perfect. This behaviour dissociates from that of other patients who have severe grammatical difficulties, but do not show any impairment in the mass nouns tasks that F.A. fails. This case is thought to demonstrate how specific grammatical rules, that are said to be stored at the lemma level of lexical retrieval, are indeed independently represented and accessible.

Aged↗
PubMed1996

Hemispheric specialization for sign language.

Most studies on sign lateralization provide inconclusive results about the role of the two hemispheres in sign language processing, whereas the cases reported in the clinical literature show sign language impairment only following left hemisphere damage, suggesting a similar neural organization to spoken languages. By discriminating different levels of processing, a tachistoscopic study found that in deaf subjects matches of sign language handshapes based on equivalence of meaning are processed faster in the right visual field, thus demonstrating a left hemisphere superiority.

Adolescent↗
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↗
PubMed1996

Dichaptic scanning of Braille letters by skilled blind readers: lateralization effects.

Dichaptic scanning of Braille letters was studied in 14 skilled blind readers, using Posner's paradigm. A right-hand (left-hemisphere) advantage was found when letters could be matched on the basis of their names (Name Identity Condition), a genuinely linguistic task, while no effects of lateralization appeared when matching could be performed on the basis of perceptual identity (Perceptual Identity Condition) or on "Different" responses. This result provides information about the cerebral lateralization of Braille reading and casts doubts about the current claim that linguistic material, when presented in the tactile modality, is initially analysed in a spatial code by the right hemisphere.

Adolescent↗