Giampiero Villa

On the Basis for the Agrammatic's Difficulty in Producing Main Verbs

Current theories of agrammatism do not provide a clear explanation for the co-occurrence of omission of grammatical markers and main verbs in this disorder. This study tested the hypothesis that the two symptom features have distinct underlying causes. Specifically, that the omission of main verbs in agrammatic speech is caused, at least in part, by a lexical (as opposed to a syntactic) deficit. Agrammatic and anomic aphasics and normal controls were given an object and action naming test. Agrammatic patients showed a marked impairment in naming actions in contrast to anomic aphasics and normal controls who named actions better than objects. The action naming impairment in agrammatic patients was interpreted as evidence for the lexical deficit hypothesis of verb omission in the speech of these patients and as a demonstration that agrammatism is a heterogeneous disorder that implicates damage to both lexical and syntactic mechanisms.

The Role of the Graphemic Buffer in Spelling: Evidence from a Case of Acquired Dysgraphia

Information processing models of spelling assume that an abstract graphemic representation of the to-be-written word must be generated at some point in the spelling process. This representation specifies the orthographic structure-the sequence of letters-that must be produced. How these graphemic representations are generated in the course of spelling is currently a much debated issue. One class of models assumes that the graphemic representations of familiar and novel words are generated by a single processing mechanism (e.g. Campbell, 1983). Another class of models assumes that the graphemic representations of familiar words are addressed directly in a graphemic lexicon whereas the graphemic representations for novel words (or nonwords) are computed through the application of a Phoneme-Grapheme Conversion Mechanism (e.g., Patterson, in press; Caramazza, Miceli, & Villa, 1986). However, independently of the class of model one adopts for the generation of graphemic representations, there is the issue of how these representations are processed further in the course of spelling. That is, we must specify the types of processes that transform an abstract graphemic representation into a form that is suitable for guiding motor output processes (see Margolin, 1984). Thus, we can consider the spelling process as consisting of two stages: First, those processes involved in the generation of a graphemic representation and, second, those processes involved in using the computed graphemic representation to generate the proper graphomotor processes for oral and written spelling.

Sensitivity and specificity of some neuropsychological markers of Alzheimer dementia.

A standardized neuropsychological test battery was administered to 167 patients with different forms of mild-to-moderate dementia: probable Alzheimer dementia (AD: n = 49), multi-infarct dementia (n = 43), idiopathic Parkinson disease with dementia (n = 35), depressive pseudodementia (n = 26), and progressive supranuelear palsy (n = 14). Results obtained were used (a) to analyze the profiles of cognitive impairment shown by the different dementia groups; (b) to assess the incidence of some neuropsychological patterns that we hypothesized to be more characteristic of AD, in the various groups; and hence (c) to evaluate the reliability of these patterns as diagnostic markers of AD. Four of the patterns investigated were derived from a verbal learning task (Reys Auditory Verbal Learning test): (1) absence of the primacy effect; (2) tendency to produce intrusion errors during free recall of a word list; (3) absolute decay of memory trace; and (4) tendency to produce false alarms during delayed recognition of the same word list. Two additional patterns were derived from visual-spatial tasks (copying drawings and Ravens Coloured Progressive Matrices): (5) occurrence of the closing-in phenomenon in copying drawings; and (6) tendency to choose globalistic or odd responses in Ravens matrices. Though all the six patterns were somewhat useful for identifying AD patients, no pattern met the criteria of being both highly sensitive and highly specific, which should characterize an ideal marker. In fact, intrusions and false alarms were observed in many AD patients, but also in patients affected by other forms of dementia. The absence of the primacy effect, the closing-in phenomenon, and the absolute decay of memory trace were more specific, but could be observed in only one-third of AD patients. We also computed the number of positive patterns shown by each patient and assumed the presence of two or more patterns as a global index suggestive of a dementia of the Alzheimer type. With this cumulative method, a higher level of sensitivity and specificity was achieved in the identification of AD patients.

Focal brain lesions and intelligence: A study with a new version of Raven's colored matrices

Contrasting results have been obtained in previous investigations, which have used the standard version of Ravens Colored Progressive Matrices for studying the effects of localized brain lesion on visual-spatial intelligence. Some of these discrepancies might be due to the fact that specific factors, such as unilateral spatial neglect, could contribute to decreased performance obtained on Ravens test by patients with focal brain lesions. A new set of Colored Matrices, devised to minimize the influence of unilateral spatial neglect without changing the essential features of the original task, was therefore constructed. The test was administered to 76 normal controls, 74 right brain-damaged patients, 87 aphasics, and 61 nonaphasic left brain-damaged patients, in order to study the effect of laterality of lesions and of language impairment on Ravens scores. The results show that, if the influence of unilateral spatial neglect is minimized and Ravens scores are corrected in reference to age, educational level, and lesion size, then: no significant differences are observed between right and left brain-damaged patients; aphasics score worse than nonaphasic left brain-damaged patients; impairment is greater in patients with Wernickes and Global aphasia (i.e., in patients with severe language comprehension disorders) than in patients classified as Brocas, Anomic, or Conduction aphasia; impairment is greater in patients with semantic-lexical discrimination errors than in patients free from semantic-lexical comprehension disorders.

Influence of age, sex, literacy and pathologic lesion on incidence, severity and type of aphasia

The influence of sex, age, educational level and pathologic lesion on incidence, severity and clinical form of aphasia was investigated in 390 right‐handed, left brain‐damaged patients. Sex and educational level were not related to any parameter. Etiology of lesion and age were related to both incidence and type of aphasia. Incidence of aphasia increased with age and was higher in patients with cerebrovascular accidents than in subjects with other types of brain lesions. Non‐fluent forms of aphasia were more frequent in young patients suffering from acute cerebrovascular accidents, whereas anomia prevailed in neoplastic subjects and Wernickes aphasia increased regularly in frequency with age. Some tentative explanations of these findings are discussed.

Neuropsychological tests and [99mTc]-HM PAO SPECT in the diagnosis of Alzheimer's dementia

Twenty-three patients with Alzheimers dementia (AD) in relatively early stages and 40 patients with other cognitive disorders of vascular or degenerative aetiology underwent neuropsychological examination and [99mTc]-HM PAO single photon emission computed tomography (SPECT). In contrast to the commonly accepted notion of a posterior temporoparietal reduction of tracer uptake as the typical SPECT pattern of AD, the most consistent feature found in the SPECT images of our AD patients was a hippocampal uptake deficit, associated with a variable degree of temporal, parietal and frontal deficit (extending from the posterior to the anterior regions), according to the severity of the disease. These results support the theory of AD as a “hippocampal dementia”, at least in the early stages. Neuropsychological tests were found to be somewhat more specific and more accurate than SPECT in distinguishing AD from non-AD cases.

Some anatomo-clinical aspects of phonemic and semantic comprehension disorders in aphasia

60 aphasic patients, affected by localized lesions of the left hemisphere and classed as Brocas, Global, Conduction, Amnestic or Wernickes aphasia received 1 phoneme discrimination test and 3 semantic‐lexical discrimination tests. The aim of the study consisted in investigating the relationships between phoneme and semantic‐lexical discrimination disorders, the clinical form of aphasia and the anatomic locus of the cerebral lesion.

Neurophysiological study of normal pressure hydrocephalus

A neuropsychological Mental Deterioration Battery (MDB) was used to identify deterioration profiles of 43 patients afflicted with normal pressure hydrocephalus (NPH) (n= 18) or other forms of dementia (n= 25). The NPH patients submitted to a shunt‐intervention (n= 10) were also evaluated after surgery. A comparison of profiles, obtained from the experimental and control groups, shows that NPH patients seem to be more impaired in tests designed to detect frontal lobe involvement. Some implications of the relatively greater impairment of frontal functions in NPH dementia are discussed.