Biomedical subjects

Michele Miozzo

Publications and source records attributed to Michele Miozzo.

6 recordsLinked to original sources

PubMed2003

On the processing of regular and irregular forms of verbs and nouns: evidence from neuropsychology.

Following acquired brain damage, a native English speaking patient (AW) encountered problems accessing phonology in speech production, while her ability to access word meaning appeared to be intact. In a series of tasks, AW was presented either with a verb, and was asked to produce its past tense or past participle (walk --> "walked"), or with a noun, and was asked to produce its plural (glove --> "gloves"). A stark dissociation was found: while AW responded accurately with regular forms of verbs (walked) and nouns (gloves), performance was significantly less accurate with irregular forms (found; children). The appearance of a selective deficit for irregular forms in conditions of impaired lexical access is in line with dual-mechanism accounts, which proposes that irregular forms are specified in the lexicon whereas regular forms are computed via rule-based mechanisms. In contrast, AW's data are problematic for connectionist accounts that do not posit separate mechanisms for processing regular and irregular forms, including the connectionist model recently proposed by Joanisse and Seidenberg (Proceedings of the National Academy of Sciences USA 96 (1999) 7592) which successfully simulated a variety of earlier neuropsychological findings. Analyses of AW's responses shed light on further details of the representation and processing of regular and irregular inflected forms.

Aged↗

PubMed2003

When more is less: a counterintuitive effect of distractor frequency in the picture-word interference paradigm.

Pictures were shown with superimposed word distractors of high and low frequency. Low-frequency distractors produced greater interference on picture naming than did high-frequency distractors. This distractor frequency effect was not affected by manipulations that facilitated or hindered distractor recognition. Interference was reduced for distractors that were read aloud several times prior to being shown in the picture-naming task. Together these findings suggest that the distractor frequency effect has its locus at some stage of lexical access for production. Other findings further constrain hypotheses about which level of speech production is involved in the effect. The distractor frequency effect has implications for models of lexical processing in speaking as well as for accounts of picture-word interference and the frequency effect.

Humans↗

PubMed2003

Where do perseverations come from?

RB, a patient with probable Alzheimer's disease, makes continuous perseverations of single letters when writing (e.g. fruit-->fruuit), particularly on high frequency letters. An analysis of her errors reveals that her perseverations do not reflect letter substitutions or transpositions, nor do they suggest difficulty with geminates. No continuous perseverations were found in oral production, in graphic and simple motor tasks, and in oral spelling. RB's data do not support an attention deficit as the basis of her continuous perseverations. It is proposed that a deficit at the level of abstract letter representations is the source of RB's perseverations. The implications of this conclusion for accounts of perseveration and of spelling models are discussed.

Aged↗

PubMed2002

The organization of letter-form representations in written spelling: evidence from acquired dysgraphia.

We report on an Italian brain-damaged patient with impaired written spelling. The patient's errors, in different fonts and scripts, consist mainly of letter substitutions (e.g., filo [thread] --> TILO). The results of various tests indicate that letter substitution errors arise because of a deficit in accessing the letter-form representations supporting written spelling. Letter substitutions occurred predominantly between letters with common strokes (e.g., C and G; b and p). Similarities in terms of global letter shape or letter sound were not valid predictors of letter substitution errors. Letter frequency, consonant-vowel status, and letter gemination were factors affecting letter substitution errors. The results of our investigation suggest that information about letter strokes are stored at the level of letter-form representations, and that access to these representations is sensitive to letter frequency. The results further indicate that letter-form representations do not specify whether a letter is a consonant or a vowel, or is a geminate.

Agraphia↗

PubMed2002

The absence of a gender congruency effect in romance languages: a matter of stimulus onset asynchrony?

Using the picture-word interference paradigm, H. Schriefers and E. Teruel (2000) found that in German the grammatical gender of the distractor word affects the production of phrases composed of article+picture name: Latencies were longer for picture-word pairs of different genders. However, the effect was found only at positive stimulus onset asynchronies (SOAs; i.e., when pictures were presented 75 or 150 ms earlier than word distractors). This gender congruency effect is not obtained in Romance languages. The present article examines whether in these languages, as in German, the effect appears at positive SOAs. No effect was observed in Italian and Spanish at positive SOAs. An account is proposed to explain why the gender congruency effect is obtained in Germanic (Dutch and German) but not in Romance languages.

Female↗

PubMed2002

Evidence for a cascade model of lexical access in speech production.

How word production unfolds remains controversial. Serial models posit that phonological encoding begins only after lexical node selection, whereas cascade models hold that it can occur before selection. Both models were evaluated by testing whether unselected lexical nodes influence phonological encoding in the picture-picture interference paradigm. English speakers were shown pairs of superimposed pictures and were instructed to name one picture and ignore another. Naming was faster when target pictures were paired with phonologically related (bed-bell) than with unrelated (bed-pin) distractors. This suggests that the unspoken distractors exerted a phonological influence on production. This finding is inconsistent with serial models but in line with cascade ones. The facilitation effect was not replicated in Italian with the same pictures, supporting the view that the effect found in English was caused by the phonological properties of the stimuli.

Analysis of Variance↗