Riccardo Pignatti

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.

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: FMR1 premutation female carriers

Neuropsychological investigations of FMR1 premutation carriers without FXTAS present one domain resulting in contradictory findings, namely that of mathematical skills. One reason for this might be that standard clinical batteries used so far may be inadequate to uncover precise deficits within specific mathematical skills. In fact, these batteries do not clearly distinguish between specific mathematical abilities and are therefore likely to provide only a generic indication of a deficit. Mathematical skills in a group of females with FMR1 premutation were investigated through the use of an extensive, theoretically grounded battery of mathematical tasks, encompassing counting, number comprehension, numerical transcoding, calculation skills and arithmetic principles. Moreover, the mental representation of numbers was assessed by studying the Spatial Numerical Association of Response Codes (SNARC) effect and mental number line (MNL) bisection. The FMR1 premutation group (N=18) comprised 29-50 years old women of normal intelligence, who were individually matched on age, sex and education to a group of healthy participants (N=18). Specific yet subtle weaknesses were detected on processes of basic number understanding such as dealing with analogue scales and certain aspects of number transcoding, in the presence of otherwise spared calculation abilities.

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.

Effect of optical flow versus attentional strategy on gait in Parkinson's Disease: a study with a portable optical stimulating device

BackgroundSeveral studies have demonstrated the capability of PD subjects to improve gait if appropriate visual cues are provided. Possible explanations referred to attentional factors and to the presence of optic flow on peripheral vision. The aim of the present study was to evaluate separately these two mechanisms in a group of fifteen subjects with Parkinsons Disease at different stages and in a group of ten age-matched controls.MethodsA microprocessor-controlled portable device implementing two different optical stimulation modalities has been used: bilateral continuous optic flow and unilateral reciprocal optical stimulus that is synchronized to the swing phase of gait. The latter allowed for the implementation of an attentional strategy.ResultsResults showed that mild PD subjects (H&Y<= 2) are responsive to forward oriented optic flow which produces an increment of gait cadence (+ 7.8%) and velocity (+ 8.1%) (p < 0.05), while PD subjects at more advanced stages (H&Y>2) tend to be more responsive to the attentional strategy, through an increase of stride length (+ 19.8%) and a compensatory decrease of cadence (- 16.2%).ConclusionAlthough stated with caution due to the limited number of considered subjects, a possible descriptive model explaining the above findings is proposed, which correlates the different responsiveness to visual stimulation strategies with the progression of pathology and the consequent changes on the activation levels of the involved motor and associative areas.

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.

Sleep dysfunctions influence decision making in undemented Parkinson's disease patients: a study in a virtual supermarket

In the early-middle stages of Parkinsons disease (PD), polysomnographic studies show early alterations of the structure of the sleep, which may explain frequent symptoms reported by patients, such as daytime drowsiness, loss of attention and concentration, feeling of tiredness. The aim of this study was to verify if there is a correlation between the sleep dysfunction and decision making ability. We used a Virtual Reality version of the Multiple Errand Test (VMET), developed using the NeuroVR free software (http://www.neurovr2.org), to evaluate decision-making ability in 12 PD not-demented patients and 14 controls. Five of our not-demented 12 PD patients showed abnormalities in the polysomnographic recordings associated to significant differences in the VMET performance.

Carpal tunnel syndrome and oral contraceptive drugs: risk or protective factor?

In view of the prevalence of carpal tunnel syndrome (CTS) in females (prevalence 4:1) and other gender-related CTS risk factors (pregnancy and menopause) we hypothesized that hormonal factors could influence the pathogenesis of the syndrome. We thus set out to evaluate the association between the use of oral contraceptive drugs (ORCDs) and CTS as a way to gain insight into the relationship between hormonal factors and CTS. Some data suggest a positive association between ORCDs and CTS (Sabour and Fadel 1970; Vessey et al. 1990) but these data lack electromyographic evaluation supporting the CTS diagnosis. In another study in which CTS was diagnosed by electromyography the authors found a negative association (De Krom et al. 1990). We recently studied 189 consecutive females (mean age 34.9 +/- 7.7 years; range 15-46) who presented with a painful CTS complaint and who were not obese or diabetic (other CTS risk factors). The patients were divided into two groups (group A: women under 35 years of age; group B: women over 35 years) and further divided into three subgroups: ORCD subgroup included women currently taking ORCDs no ORCD subgroup included those who had never taken them and past ORCD subgroup included women who had taken ORCDs in the past. All patients underwent electromyography and electroneurography to confirm the diagnosis of CTS. (excerpt)

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).