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Biomedical subjects

G Miceli

Publications and source records attributed to G Miceli.

At least 19 recordsLinked to original sources
PubMed1996

The treatment of anomia resulting from output lexical damage: analysis of two cases.

This study describes a treatment project, carried out with two anomic subjects, RBO and GMA failed to name pictures correctly as a consequence of damage to phonological lexical forms; their ability to process word meaning was unimpaired. Words that were consistently comprehended correctly, but produced incorrectly by each subject, were identified. Some words were treated, whereas some served as the control set. A significant improvement was observed in both subjects. As predicted by the model of lexical-semantic processing used as the theoretical background for the study, improvement was restricted to treated items and did not generalize to untreated words, not even to words that were semantically related to those administered during treatment. Improvement was long-lasting, as shown by the fact that 17 months post-therapy GMA's performance on treated words was still significantly better than before treatment. These results are discussed in relation to the claim that cognitive models can be profitably used in the treatment of language disorders.

Adult↗
PubMed1995

Selective deficit in processing double letters.

This paper reports a patient with a selective difficulty in spelling words and pseudowords with geminate (double) consonants. In all writing tasks, deletions of a geminate consonant occurred ten times more often than deletions of a consonant in a non-geminate cluster. In addition, the probability of substituting both geminate consonants was indistinguishable from the probability of substituting one consonant in a non-geminate cluster; and, the probability of substituting only one geminate consonant was close to zero, and significantly lower than the probability of substituting one consonant in a non-geminate cluster. This pattern of performance is consistent with the hypothesis that grapheme quantity and identity are separately represented in orthographic representations. The fact that these errors occurred in the absence of a significant number of geminate transpositions is interpreted as support for the hypothesis that letter gemination is specified by a "doubling feature."

Adult↗
PubMed1994

Morphological errors and the representation of morphology in the lexical-semantic system.

Neuropsychological studies support the hypothesis that morphology is represented autonomously, both at the level of word meaning and at the level of word form. In output processes, morphologically organized semantic information activates lexical representations of roots and affixes, which are composed before production. In input processes, the stimulus is parsed along the morphological dimension, to access root and affix lexical representations, which in turn activate morphologically organized semantic information. Inflectional and derivational morphology are represented independently in the lexicon. Inflected words are fully decomposed; derived words are decomposed into base form+inflection. In aphasia, morphological errors in transcoding tasks always co-occur with semantic and/or phonemic errors. Morphological errors in transcoding tasks require combined damage to morphological representations in the semantic-lexical system and to sublexical conversion procedures; they co-occur with semantic errors when also root representations are damaged. The co-occurrence of morphological and phonemic errors can be accounted for by several hypotheses, but its theoretical meaning is still uncertain.

Aphasia↗
PubMed1994

The interaction of lexical and sublexical processes in reading, writing and repetition.

It has recently been proposed that in the course of repetition, reading aloud and writing to dictation, lexical representations are activated and selected for output by the joint operation of the semantic system and of sublexical conversion mechanisms--the Summation Hypothesis [Hillis and Caramazza, Brain Lang. 40, 106-144, 1991]. The hypothesis predicts that semantic errors in oral reading and in writing to dictation should only occur when both the semantic system and the sublexical component involved in that task (orthography to phonology and phonology to orthography conversion, respectively) are damaged. The performance of Italian patient E.C.A. indicates damage to the semantic system, and to sublexical phonology to phonology and phonology to orthography conversion mechanisms, but with substantial sparing of sublexical orthography to phonology conversion processes. In agreement with expectations derived from the Summation Hypothesis, E.C.A. produced semantic errors in repetition and in writing to dictation, but not in reading aloud. The paucity of semantic errors in speakers of languages with relatively transparent orthographies is discussed in the context of the Summation Hypothesis.

Aged↗
PubMed1991

Selective impairment of thematic role assignment in sentence processing.

We report the performance of a brain-damaged subject showing a particularly pure dissociation between impairment in processing thematic roles and spared ability to process the morphological structure of sentences. The thematic role processing impairment was observed in both comprehension and production of active and passive reversible sentences, although it was more severe for the latter sentence type. This pattern of performance poses interesting challenges for current conceptions of the nature of language breakdown in aphasia and for models of normal sentence processing.

Aphasia, Wernicke↗
PubMed1991

The interaction of lexical and non-lexical processing mechanisms: evidence from anomia.

Patient SF presented with a selective deficit in naming, in the presence of normal auditory, visual and pictorial input processing, and of normal comprehension. The naming disorder was independent of input modality, and resulted in the inability to respond to low-frequency items. The analysis of the patient's performance in the repeated administration of the same set of pictures for oral naming and for written naming demonstrated that both tasks were disrupted to a similar extent--high consistency values were observed both across and within modality. Thus, the profile of the naming disorder observed in this patient was consistent with damage to phonological and orthographic output lexicons. SF's performance in reading and writing was apparently at odds with this account, as he was able to read aloud words with lexically-assigned stress, and to write to dictation words whose spelling is also determined lexically. The co-occurrence of the inability to activate output lexical representations in both oral and written picture naming, in the context of normal ability to activate the same representations in reading and in writing is consistent with the notion that phonological and orthographic output lexicons are distinct, but interact with nonlexical conversion mechanisms.

Anomia↗
PubMed1991

[Plasma levels of beta-endorphin in obese subjects with normal glucose tolerance test and in diabetics].

Forty obese subjects with normal glucose tolerance test (NGTT) thirteen diabetic obese subjects and sixteen normal subjects were studied to evaluate the possible interactions between beta-endorphin (B-Ep) and glucose homeostasis. On the basis of baseline B-Ep levels, two subgroups were selected: one group with normal mean values of B-Ep (7.02 +/- 0.59 pmol/l); another group with elevated mean values of B-Ep (18.95 +/- 1.52 pmol/l). No differences between these subgroups were found as regards body mass index (BMI), insulin and glucagon levels. Normal B-Ep values were found in diabetic obese subjects. No significant correlation was found between B-Ep and BMI, insulin or glucagon. Considering that B-Ep is involved in eating behavior and on the basis of our results, we suggest that elevated B-Ep levels can be found only in those obese NGTT subjects whose obesity is probably related to an abnormal modulation of food intake, such as hyperphagia.

Adult↗
PubMed1990

The structure of graphemic representations.

The analysis of the spelling performance of a brain-damaged dysgraphic subject is reported. The subject's spelling performance was affected by various graphotactic factors, such as the distinction between consonant and vowel and graphosyllabic structure. For example, while the subject produced many consonant and vowel deletion errors when these were part of consonant and vowel clusters, respectively (e.g., sfondo----sondo; giunta----gunta), deletions were virtually never produced for single consonants flanked by two vowels (e.g., onesto----oesto) or for single vowels flanked by two consonants (e.g., tirare----trare). The demonstration that graphosyllabic factors affect spelling performance disconfirms the hypothesis that graphemic representations consist simply of linearly ordered sets of graphemes. It is concluded that graphemic representations are multidimensional structures: one dimension specifies the grapheme identities that comprise the spelling of a word; a second dimension specifies the consonant/vowel status of the graphemes; a third dimension represents the graphosyllabic structure of the grapheme string; and, a fourth dimension provides information about geminate features.

Agraphia↗
PubMed1990

Rabies reference vaccine for use as a regional standard for Latin America and the Caribbean countries.

A candidate rabies reference vaccine of suckling mouse brain (SMB) origin was prepared and standardized at the Pan American Zoonoses Center (PAHO/WHO) and evaluated in a collaborative study involving seven laboratories. On the basis of three different tests, its potency, immunogenicity, and stability were demonstrated to be satisfactory. The vaccine was proposed for consideration of the Latin American and Caribbean countries as a regional standard to determine the potency of SMB vaccines, the most widely used in the Region.

Animals↗
PubMed1990

Increase in red cell lactate concentration and its reduction by isologous plasma in NIDDM subjects.

We determined red blood cell (RBC) lactate concentrations in NIDDM subjects using an experimental protocol in which diabetic RBCs were incubated over 8 hours both with own plasma and with normal plasma. Furthermore, normal RBCs were incubated both with own plasma and with diabetic plasma. The results indicate that the increased lactate concentrations in RBCs from NIDDM subjects decreased significantly when the same RBCs were incubated in normal plasma. Conversely, lactate concentrations in normal RBCs increased significantly when RBCs were incubated in diabetic plasma. Thus, other than muscle and adipose tissue, RBCs may contribute to increase lactate release for hepatic gluconeogenesis in NIDDM and we suggest that there may be extrinsic plasmatic factor(s) capable of stimulatory effect on diabetic RBC glycolytic pathway.

Adult↗
PubMed1989

Variation in the pattern of omissions and substitutions of grammatical morphemes in the spontaneous speech of so-called agrammatic patients.

We describe the patterns of omissions (and substitutions) of freestanding grammatical morphemes and the patterns of substitutions of bound grammatical morphemes in 20 so-called agrammatic patients. Extreme variation was observed in the patterns of omissions and substitutions of grammatical morphemes, both in terms of the distribution of errors for different grammatical morphemes as well as in terms of the distribution of omissions versus substitutions. Results are discussed in the context of current debates concerning the possibility of a theoretically motivated distinction between the clinical categories of agrammatism and paragrammatism and, more generally, concerning the theoretical usefulness of any clinical category. The conclusion is reached that the observed heterogeneity in the production of grammatical morphemes among putatively agrammatic patients renders the clinical category of agrammatism, and by extension all other clinical categories from the classical classification scheme (e.g., Broca's aphasia, Wernicke's aphasia, and so forth) to more recent classificatory attempts (e.g., surface dyslexia, deep dysgraphia, and so forth), theoretically useless.

Adult↗
PubMed1988

Dissociation of inflectional and derivational morphology.

A patient is described who makes morphological errors in spontaneous sentence production and in repetition of single words. The great majority of these errors were substitutions of inflectional affixes. The patient did make some derivational errors in repeating derived words but almost never made such errors for nonderived words. The inflectional errors for adjectives and nouns occurred mostly on the plural forms for nouns and adjectives and on the feminine form for adjectives. For verbs, inflectional errors were produced for all tense, aspect, and mood forms. There were no indications that these latter verb features constrained the form of inflectional errors produced. The results are interpreted as support for the thesis that morphological processes are located in the lexicon but that inflectional and derivational processes constitute autonomous subcomponents of the lexicon.

Aphasia↗
PubMed1987

[Antiviral activity of a chemical contraceptive (nonoxynol-9)].

The aim of this study was to evaluate, in vitro, the antiviral activity of a chemical contraceptive (Nonoxynol-9). The results have demonstrated that such a compound is able to inhibit the infectivity of enveloped viruses. It seems that the activity of this contraceptive is due to the lesion of the envelope.

Cell Line↗
PubMed1986

Anomia with and without lexical comprehension disorders.

Anomic patients are usually described as free from language comprehension disorders, but the status of lexical comprehension in anomia is still controversial. Most anomic patients are impaired on tasks of semantic-lexical discrimination, but some of them do not present clear signs of semantic-lexical deficit at the receptive level. The aim of the present research was to elucidate the nature of word-finding disturbances by contrasting results obtained by anomic patients with and without lexical comprehension disorders on a number of variables, namely severity of anomia, implicit knowledge of words that patients failed to name, presence of verbal-semantic paraphasias, and scores obtained on a test of phoneme discrimination and on the "Token Test." The results of our investigation seem to suggest that there are two types of anomia, caused by the impairment of two different sets of mechanisms. In "purely expressive anomia" the locus of defect seems to be near to the stage in which the selected lexical item is specified into the appropriate phonological form. In "anomia with lexical comprehension disturbances" the locus of defect seems to be much deeper within the lexicon, so that the semantic disorder affects both the expressive and the receptive levels in a roughly comparable manner.

Adult↗
PubMed1985

Cognitive analysis of a case of pure dysgraphia.

An Italian patient with a pure dysgraphia who incorrectly spelled words and nonwords is described. The spelling errors made by the patient were not affected by lexical factors (e.g., frequency, form class) and were qualitatively the same for words and nonwords. The pattern of writing performance is discussed in relation to current models of writing and, specifically, in relation to the role of the Output Grapheme Buffer and Phoneme-Grapheme Conversion in writing.

Cerebrovascular Disorders↗
PubMed1984

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.

Adult↗
PubMed1983

The production of morphological and lexical opposites in aphasia.

Four unselected groups of Broca's, Wernicke's, conduction, amnesic aphasic patients and a group of normal controls were asked to produce the best opposite of 60 adjectives. For half of the stimuli the expected opposite was morphologically related to the stimulus word (e.g. "formal"/"informal"), for the other half it could be obtained only by selecting a new base-form within the lexicon (e.g. "good"/"bad"). Following some neurolinguistic observations by Hécaen et al., it was predicted that amnesic patients should produce mainly morphological opposites, whereas conduction aphasics should produce mainly lexical antonyms. Results confirmed the predictions, since amnesic aphasics showed a prevalent impairment in the selection lexical opposites, whereas conduction aphasics showed a selective impairment in the production of morphological antonyms.

Anomia↗