Ileana Mori

Is math lateralised on the same side as language? Right hemisphere aphasia and mathematical abilities

The main purpose of the present study was to learn how mathematical abilities are located and develop in the brain with respect to language. Mathematical abilities were assessed in six right-handed patients affected by aphasia following a lesion to their non-dominant hemisphere (crossed aphasia) and in two left-handed aphasics with a right-sided lesion. Acalculia, although in different degrees, was found in all cases. The type of acalculia depended on the type of aphasia, following patterns that have been previously observed in the most common aphasias resulting from left hemisphere lesions. No sign of right hemisphere or spatial acalculia (acalculia in left lateralised right-handed subjects) was detected. These results suggest that, as a rule, language and calculation share the same hemisphere. A primitive computational mechanism capable of recursion may be the precursor of both functions.

Genetics and mathematics : Evidence from Prader-Willi syndrome

Mathematical abilities were tested in people with Prader-Willi syndrome (PWS), using a series of basic mathematical tasks for which normative data are available. The difference between the deletion and the disomy variants of this condition was explored. While a wide phenotypic variation was found, some basic findings emerge clearly. As expected from previous literature, deletion and disomy participants were found to differ in their degree of impairment, with disomy being overall the most spared condition. However, the tasks selectively spared in the disomy condition are not necessarily the easiest ones and those that discriminate less the PWS group from controls. It rather seems that disomy patients are spared, with respect to deletion, in tasks entailing transcoding and comparison of numbers in the Arabic code. Overall a particular difficulty was detected in reliably performing parity judgments. This task has been shown to be very frequently spared after a brain injury, even in severe aphasic conditions. The most interesting result is the sparing in analog number scale, whereby PWS seem, overall, to outperform controls. This finding may help in understanding previously reported, surprising results about cognitive skills in PWS. Elevated performances in PWS may result from life-long hyper-reliance on one visuo-spatial system in presence of underdevelopment of the other.

When two and too don't go together: A selective phonological deficit sparing number words

We report the case of an Italian speaker (GBC) with classical Wernickes aphasia syndrome following a vascular lesion in the left posterior middle temporal region. GBC exhibited a selective phonological deficit in spoken language production (repetition and reading) which affected all word classes irrespective of grammatical class, frequency, and length. GBCs production of number words, in contrast, was error free. The specific pattern of phonological errors on non-number words allows us to attribute the locus of impairment at the level of phonological form retrieval of a correctly selected lexical entry. These data support the claim that number words are represented and processed differently from other word categories in language production.

Exploring Patterns of Unwanted Behaviours in Adults with Prader-Willi Syndrome

BACKGROUND Obsessive-compulsive (O-C) traits, and excessive food intake are well known behavioural manifestations among individuals with Prader-Willi Syndrome (PWS). Other unwanted behaviours are also frequently observed, but they need a more specific investigation, especially in the adult population. METHODS The behaviour of 31 PWS adults was investigated via the Symptom Checklist-90-Revised (SCL-90-R), the Yale-Brown Obsessive Compulsive Scale Symptom Checklist (Y-BOCS-SC), and the Prader-Willi Behavioural Checklist (PBC). The PBC is a quick screening questionnaire prompted specifically for the investigation on adults with PWS. RESULTS Statistical clustering revealed two patterns of unwanted behaviours from the PBC. Behaviours belonging to the first cluster (e.g., Excessive food intake, Skin picking) appear to be linked to the usual phenotypic manifestation of PWS. By contrast, many other behaviours (e.g., some O-C symptoms and aggressive actions) could show a relationship also to individual psychopathologies. CONCLUSIONS Both internal (Anxiety and Depression) and external (Hostility) difficulties in managing impulses should account for individually distinct behaviours in adults with PWS.

A relative vowel deficit in aphasia sparing the lexicon of numbers

It is a well-known fact that, in general, in patients affected by aphasia (as well as in normal speakers) phonemic errors occur more frequently on consonants than on vowels (Blumstein, 1988). Perhaps just because this effect has been studied on groups of patients, where individual differences are easily lost, reports of the reverse effect, more errors on vowels than on consonants, are extremely rare. Indeed, only two studies reporting a superiority in the production of consonants with respect to vowels appear in literature (Caramazza, Chialant, Capasso, & Miceli, 2000; Romani, Grana, & Semenza, 1996).