Alessia Granà

Finger–digit compatibility in Arabic numeral processing

Finger–digit response compatibility was tested by asking participants to identify Arabic digits by pressing 1 of 10 keys with all 10 fingers. The direction of the finger–digit mapping was varied by manipulating the global direction of the hand–digit mapping as well as the direction of the finger–digit mapping within each hand (in each case, from small to large digits, or the reverse). The hypothesis of a left-to-right mental number line predicted that a complete left-to-right mapping should be easier whereas the hypothesis of a representation based on finger counting predicted that a counting-congruent mapping should be easier. The results show that when all 10 fingers are used to answer, a mapping congruent with the prototypical finger-counting strategy reported by the participants leads to better performance than does a mapping congruent with a left-to-right oriented mental number line, both in palm-down and palm-up postures of the hands, and they demonstrate that finger-counting strategies influence the way that numerical information is mentally represented and processed.

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.

The validity of the hospital anxiety and depression scale and the geriatric depression scale in Parkinson's disease.

We assessed the concurrent validity of the Hospital Anxiety and Depression Scale (HADS) and the Geriatric Depression Scale (GDS) against the Hamilton Rating Scale for Depression (Ham-D) in patients with Parkinson’ disease (PD). Forty-six non-demented PD patients were assessed by a neurologist on the Ham-D. Patients also completed four mood rating scales: the HADS, the GDS, the VAS and the Face Scale. For the HADS and the GDS, Receiver Operating Characteristics (ROC) curves were obtained and the positive and negative predictive values (PPV, NPV) were calculated for different cut-off scores. Maximum discrimination between depressed and non-depressed PD patients was reached at a cut-off score of 10/11 for both the HADS and the GDS. At the same cut-off score of 10/11 for both the HADS and the GDS, the high sensitivity and NPV make these scales appropriate screening instruments for depression in PD. A high specificity and PPV, which is necessary for a diagnostic test, was reached at a cut-off score of 12/13 for the GDS and at a cut-off score of 11/12 for the HADS. The results indicate the validity of using the HADS and the GDS to screen for depressive symptoms and to diagnose depressive illness in PD.

Patterns of phonological errors as a function of a phonological versus an articulatory locus of impairment

We present the case of two aphasic patients: one with fluent speech, MM, and one with dysfluent speech, DB. Both patients make similar proportions of phonological errors in speech production and the errors have similar characteristics. A closer analysis, however, shows a number of differences. DBs phonological errors involve, for the most part, simplifications of syllabic structure; they affect consonants more than vowels; and, among vowels, they show effects of sonority/complexity. This error pattern may reflect articulatory difficulties. MMs errors, instead, show little effect of syllable structure, affect vowels at least as much as consonants and, and affect all different vowels to a similar extent. This pattern is consistent with a more central impairment involving the selection of the right phoneme among competing alternatives. We propose that, at this level, vowel selection may be more difficult than consonant selection because vowels belong to a smaller set of repeatedly activated units.

Evaluation of anxiety in Parkinson’s disease with some commonly used rating scales

This study assessed the concurrent validity of the State-Trait Anxiety Inventory (STAI), the Hospital Anxiety and Depression Scale (HADS) and the Hamilton Anxiety Scale (Ham-A) for evaluating anxiety in a group of 46 Parkinson’s disease (PD) patients. The magnitude of correlations between the scales was high (all p<0.01), indicating a good concurrent validity. The item-by item analysis indicated that the main characteristics of anxiety in PD patients were ‘inability to relax’, ‘restlessness or inability to feel calm’ and ‘feeling tense’. The association between anxiety, as measured by the HADS-A, with demographic characteristics or clinical features of PD was not significant, supporting existing data suggesting that anxiety in PD is not closely correlated with the severity of motor symptoms or the degree of disability. The HADS-A may be the most appropriate scale for documenting patient-reported anxiety in depression.SommarioQuesto studio indaga la validità nel valutare l’ansia in un gruppo di 46 pazienti con malattia di Parkinson dell’Inventario per l’ansia di stato e di tratto (STAI-Y), della Hospital Anxiety and Depression Scale (HADS) e della scala Hamilton per l’ansia (Ham-A). Il livello di correlazione tra le scale è elevato (p<0.01), indicando una buona validità convergente. L’analisi dei singoli items mostra che le principali caratteristiche dell’ansia nei pazienti con malattia di Parkinson sono “l’incapacità a rilassarsi”, “l’irrequietezza o incapacità a stare calmo” e “il sentirsi teso”. L’associazione tra l’ansia, misurata con l’HADS, e le caratteristiche demografiche del campione e/o gli aspetti clinici della malattia di Parkinson non è significativa. Tale risultato sostiene i dati presenti in letteratura che suggeriscono che l’ansia nella malattia di Parkinson non è strettamente correlata con la gravità dei sintomi motori o con il livello di disabilità.

Leftward motion restores number space in neglect

In the present study, a group of patients with left-sided neglect performed a number comparison task that co-occurred either with coherent motion in different directions or with random motion. Their performance was compared to that of a healthy control group and to a group of patients with right hemisphere damage (RHD) but no signs of neglect. The presence of leftward motion alleviated the difficulties that neglect patients typically show for a number smaller than the reference number 5 (i.e., number 4). Moreover, the standard distance effect was only present when the task co-occurred with leftward motion. These effects were not present in a group of participants with RHD without neglect or in a control group. The present data extend the effects of optokinetic stimulation (OKS) to representational neglect, suggesting that an external redirection of attention by the perception of motion may restore the altered access to the representation of the mental number line in neglect.

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.

Numbers in the Blind's “Eye”

Background Although lacking visual experience with numerosities, recent evidence shows that the blind perform similarly to sighted persons on numerical comparison or parity judgement tasks. In particular, on tasks presented in the auditory modality, the blind surprisingly show the same effect that appears in sighted persons, demonstrating that numbers are represented through a spatial code, i.e. the Spatial-Numerical Association of Response Codes (SNARC) effect. But, if this is the case, how is this numerical spatial representation processed in the brain of the blind? Principal Findings Here we report that, although blind and sighted people have similarly organized numerical representations, the attentional shifts generated by numbers have different electrophysiological correlates (sensorial N100 in the sighted and cognitive P300 in the blind). Conclusions These results highlight possible differences in the use of spatial representations acquired through modalities other than vision in the blind population.

On knowing about nothing: The processing of zero in single- and multi-digit multiplication

Background: Zero has a special role in calculation: indeed it is not obvious which representation may be invoked in multiplication or division by zero. In particular, zero as an operand, unlike any other operand, makes any quantity disappear. Aims: The study is intended to shed light on the mechanisms mediating the manipulation of zero. Methods & Procedures: Three neuropsychological patients, AF, FV, and FS, are described, whose specific pattern of preserved/impaired performance with single- and multi-digit multiplication shows selective problems with the use of zero (N×0 and 0×N). Outcome & Results: AFs performance in single- and multi-digit multiplication showed a clear dissociation between spared fact-based problems and impaired 0 rule-based problems. FV was totally unable, in multi-digit multiplication, to apply adequately the 0 rule that he could master in simple calculation. Finally, FS showed, within the rule-based problems, a clear-cut dissociation between a preserved performance on N×0 problems and an impaired performance on 0×N problems, a difficulty that almost disappeared in multi-digit multiplications. Conclusions: Overall the reported dissociations indicate that a full grasp of the concept of zero may not be used in routine calculation, and that processing of zero rather appears to rely on a collection of independent, shallow representations.

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.