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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: (I) 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.

The processing of Prepositional compounds (typical Neo-latin noun noun modifications where a head noun is modified by a prepositional phrase, e.g., midino a vento, windmill) was preliminarily studied with a group of six agrammatic aphasic patients, and, in more detail, with a further agrammatic patient (MB). Omission was the most frequent error type in naming, whereas in the other tasks (repetition, reading, writing, and completion) errors were mostly substitutions of the target preposition. This happened even with fully lexicalized compound forms, i.e., those forms where the linking preposition is syntactically and semantically opaque. These findings are interpreted in terms of a dual-route theory of lexical access to morphologically complex words. (c) 2005 Elsevier Inc. All rights reserved.

This study seeks information on the mental representation of Verb-Noun (VN) nominal compounds through neuropsychological methods. The lexical retrieval of compound nouns is tested in 30 aphasic patients using a visual confrontation naming task. The target names are VN compounds, Noun-Noun (NN) compounds, and long morphologically simple nouns (LSN). In order to check the ability to produce simple nouns and verbs in the same participants, a further visual confrontation naming task of objects and actions is used. Results of the study confirm that several patients with disproportionate verb deficit are also impaired in naming VN compounds. Data are in favor of a (de)compositional processing of compound words. A further group of patients is selectively more impaired with compound nouns than with comparably long simple nouns, irrespective of their VN or NN morphological structure. It is suggested that this impairment is to be ascribed to a specific disorder in retrieving two different lexemes with a single lexical entry. (C) 2003 Elsevier Inc. All rights reserved.

This study investigates the performance of two Italian nonfluent aphasic patients on nounadjective agreement in compounds and in noun phrases. A completion, a reading, and a repetition task were administered. Results show that both patients were able to correctly inflect adjectives within compounds, but not in noun phrases. Moreover, they were sensitive to constituent order (noun-adjective vs adjective-noun) within noun phrases, but less so within compounds, These results suggest differential processing for compounds as compared to noun phrases: While the latter require standard morphosyntactic operations that are often impaired in aphasic patients, the former can be accessed as whole words at the lexical level. () 2001 Elsevier Science (USA).

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 the authors 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 testing of 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.

We analyzed the performance of a patient (M.B.) affected by agrammatism and phonological dyslexia. M.B. was tested with a series of tasks requiring lexical retrieval of simple and morphologically complex words. The patient presented a pattern of errors that is interpreted as the result of the prominent use of the lexical routine. This pattern of errors was characterized by frequency effect more than by a difference between types of suffixes (inflectional versus derivational) or types of word. It seems that high-frequency morphologically complex items will meet stored representations, thus avoiding more costly parsing that is required for less frequent items. These results are in keeping with dual-route models of lexical representation of morphologically complex words.

Objective: This study describes a follow-up investigation of numerical abilities and visuospatial memory in a patient suffering from semantic dementia whose progressive decline of semantic memory variably affected different types of knowledge. Crucially, we investigated in detail her outstanding performance with Sudoku that has been only anecdotally reported in the previous literature. Method: We tested spatial cognition and memory, body representation, number processing, calculation, and Sudoku tasks, and we compared the patient's performance with that of matched controls. Results: In agreement with the neuroanatomical data, showing substantial sparing of the parietal lobes in the face of severe atrophy of the temporal (and frontal) regions, we report full preservation of skills known to be supported by intact parietal-basal ganglia networks, and impaired knowledge related to long-term stored declarative information mediated by temporal regions. Performance in tasks sensitive to parietal dysfunction (such as right-left orientation, finger gnosis, writing, and visuospatial memory) was normal; within the numerical domain, preserved quantity-based number knowledge dissociated from increasing difficulties with nonquantitative number knowledge (such as knowledge of encyclopedic and personal number facts) and arithmetic facts knowledge. Conclusions: This case confirms the relation between numbers and space, and, although indirectly, their anatomical correlates, underlining which abilities are preserved in the case of severe semantic loss. In addition, although Sudoku is not inherently numerical, the patient was able to solve even the most difficult pattern, provided that it required digits and not letters, showing that digits have, in any case, a specific status.

Background: Although disproportionate impairment of noun or verb retrieval has been described on the basis of the evidence from several aphasic cases since the mid 1980s, with different theoretical frames being proposed to account for noun-verb dissociation, very few studies have dealt with this dissociation in spontaneous speech. Aims: The objectives of this study were to investigate (i) whether the dissociation also emerged in connected speech, and (ii) whether the analysis of patients' narratives could shed light on the functional damage underlying their grammatical-class-specific impairment. Methods & Procedures: Two non-fluent verb-impaired patients, two fluent verbimpaired patients, and three fluent noun-impaired patients participated in this study. Their noun-verb dissociation was preliminarily assessed through a picture-naming task, following which their spontaneous speech was collected and analysed using a single-case approach, taking into consideration both lexical productivity (as indicated by the number of different tokens produced by the patients) and lexical diversity (as indicated by the number of different types and stems used by the patients). Outcomes & Results: Non-fluent verb-impaired patients tended to produce a lower proportion of verb types than unimpaired control participants, as opposed to fluent verb-impaired patients, who produced a normal verb rate in their spontaneous speech on all counting procedures. One out of three fluent noun-impaired patients produced a lower proportion of noun tokens, types, and stems compared to normal speakers. Conclusions: The data presented in this paper indicate that noun-verb dissociation as assessed in picture-naming tasks might not emerge in spontaneous speech and indicates the need for the inclusion of a lemma level in models of word production that aims at explaining grammatical-class-specific impairments in people with aphasia

Bastiaanse and Jonkers (1998) found that in verb-impaired aphasic patients verb retrieval in picture naming tasks and in spontaneous speech do not always correlate. This study aims at (i) further investigating the relationship between verb production in formal tasks and spontaneous speech, (ii) extending this analysis to noun-specific impairments and (iii) using this evidence to clarify the cognitive damage underlying noun-verb dissociation. Seven Italian aphasic patients (three noun-impaired fluent, two verb-impaired fluent and two verb-impaired non-fluent patients) participated in the study. For each patient a three-hundred-word sample of spontaneous speech was analyzed. The number of tokens, types and roots was then calculated for any of these five categories: open-class words, closed-class words, nouns, open-class verbs and closed-class verbs. These variables were analyzed using the modified t-test described by Sokal and Rohlf (1995) and the norms reported in Semenza et al. (1989). Verb-impaired patients split according to the type of aphasia they suffer from; non-fluent patients have a poor verb-type production in spontaneous speech, while fluent patients produce a normal amount of verbs. Also noun-impaired fluent patients have a reduced noun production in spontaneous speech. We argue that this different behaviour depends on the different cognitive damages underlying the dissociations and on the different impact of the frame context characterizing spontaneous speech on noun and verb retrieval. The consequence of these results on the different hypotheses on noun-verb dichotomy mental representation will be also discussed.

Introduction Many studies on aphasia have described disproportioned impairment of either verbs or nouns and have broached the issue of mental implementation of the grammatical class distinction. A clear picture has not yet been reached and, while evidence has has been found to indicate the lemma level as the possible locus of this distinction (Crepaldi et al., 2006), some alternative interpretations have been proposed (e.g., Rapp & Caramazza, 2002). These studies have focused almost exclusively on picture naming tasks, and have practically ignored the assessment of the dissociation in spontaneous speech. A remarkable exception is the study by Bastiaanse and Jonkers (1998) in which, however, the authors considered only verb-impaired patients and focused exclusively on the production of verbs. The results of this study indicate that the naming performance resulting from picture naming tasks does not always correlate with lexical retrieval in spontaneous speech. The present study aims at verifying (i) whether the disproportionate verb or noun impairment that emerges from a picture naming task is also present in spontaneous speech, and (ii) whether this occurs irrespective of the type of aphasia. Materials and Methods Seven Italian aphasic patients participated in the study. Their lexical retrieval abilities on nouns and verbs were tested by means of a picture naming task of 40 actions and 30 objects. Nouns and verbs were matched for word frequency, length and age of acquisition (see Luzzatti et al., 2002). Patients were selected according to their performance on this task and their aphasia type in order to represent the major types of noun-verb dissociation observed so far, i.e., noun-impaired fluent (n=3), verb-impaired fluent (n=2) and verb-impaired non-fluent patients (n=2). Spontaneous speech was elicited by asking the patients to describe their job, their family, their hobbies and how their speech disorder started. The spontaneous production was recorded and t

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 (Nx0 and 0xN). Outcome & Results: AF's 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 Nx0 problems and an impaired performance on 0xN 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.