Lisa S. Arduino

Word naming times and psycholinguistic norms for Italian nouns

The present study describes normative measures for 626 Italian simple nouns. The database (LEXVAR. XLS) is freely available for down-loading on the Web site http://wwwistc.ip.rm.cnr.it/material/ database/. For each of the 626 nouns, values for the following variables are reported: age of acquisition, familiarity, imageability, concreteness, adult written frequency, child written frequency, adult spoken frequency, number of orthographic neighbors, mean bigram frequency, length in syllables, and length in letters. A classification of lexical stress and of the type of word-initial phoneme is also provided. The intercorrelations among the variables, a factor analysis, and the effects of variables and of the extracted factors on word naming are reported. Naming latencies were affected primarily by a factor including word length and neighborhood size and by a word frequency factor. Neither a semantic factor including imageability, concreteness, and age of acquisition nor a factor defined by mean bigram frequency had significant effects on pronunciation times. These results hold for a language with shallow orthography, like Italian, for which lexical nonsemantic properties have been shown to affect reading aloud. These norms are useful in a variety of research areas involving the manipulation and control of stimulus attributes.

LEXICAL EFFECTS IN LEFT NEGLECT DYSLEXIA. A STUDY IN ITALIAN PATIENTS

This study investigated whether and to what extent the reading performance of six Italian right-brain-damaged patients with left neglect dyslexia was affected by lexical variables. The lexicality of responses (either words or nonwords) and the distribution of substitution vs. omission neglect errors were measured. Patients were given the following tasks: (1) reading aloud monomorphemic words of different frequencies and nonwords with different degrees of similarity to real words (Experiment 1); (2) reading aloud morphologically complex (suffixed) derived words and morphologically complex (suffixed) nonwords (Experiment 2). Patients could be distinguished in terms of their sensitivity to the lexical status of the target. Four patients exhibited lexicality effects in their reading performance, while two patients did not. The dissociation is discussed in terms of the interaction between defective visuospatial analysis, which characterises neglect, and higher-order lexical knowledge. The suggestion is made that lexical effects in neglect dyslexia reflect a relative preservation of visuospatial processing of the left side of the letter string, its absence a more severe neglect disorder. This interpretation of the occurrence of lexical effects in left neglect dyslexia in terms of severity of the spatial disorder is specific to the domain of reading, however, and does not extend to other manifestations of unilateral spatial neglect. Finally, the relationship between error type (omissions vs. substitutions) and the absence vs. presence of lexical effects is considered.

Neglect dyslexia: a review of the neuropsychological literature

Neglect dyslexia (ND) is reviewed, based on published single-patient and group studies. ND is frequently associated with right hemispheric damage and unilateral spatial neglect (USN), and typically involves the left side of the letter string. Left-brain-damaged patients showing ND, ipsilateral (left) or contralateral (right) to the side of the left-sided hemispheric lesion, have also been reported, as well as a few patients with bilateral damage, with more frequently left than right ND. As USN, ND is temporarily ameliorated by lateralized stimulations (vestibular caloric, visual prism adaptation). ND may occur independent of USN, suggesting the damage to specific visuospatial representational/attentional systems, supporting reading. ND errors comprise omission, substitution, and, less frequently, addition of letters on one side of the stimulus, resulting in words or nonwords, also with reference to the stimulus’ linguistic features. Patients with ND may show preserved lexical–morphological effects and implicit processing, up to the semantic level, of the misread string. This preserved processing is a feature of ND, shared with the USN syndrome. The mechanisms modulating error type and lexical–morphological effects are partly independent of each other. Different levels of representation of the letter string may be affected, giving rise to egocentric, stimulus-centred, and word-centred patterns of impairment. The anatomical correlates of ND include the temporo-parieto-occipital regions.

Fully transparent orthography, yet lexical reading aloud: The lexicality effect in Italian

This is the first study that reports the lexicality effect (i.e., words read better than nonwords) in Italian with fully transparent and methodologically well-controlled stimuli. We investigated how words and nonwords are read aloud in the Italian transparent orthography, in which there is an almost strict one-to-one correspondence between graphemes and phonemes. Contrary to the claim that in such orthography word naming is accomplished primarily by the nonlexical assembly route, we found that words were named faster than nonwords, regardless of their frequency (high or low) or the composition of the experimental list (pure vs. mixed blocks). These findings show that the lexical route is the main one used by readers even in a language with a transparent orthography.

Two different mechanisms for omission and substitution errors in neglect dyslexia

Neglect dyslexia is a reading disorder often associated with right-sided brain lesions. In reading single words, errors are mostly substitutions or omissions of letters that occupy the left-sided positions. Typically, these errors have been thought to depend on a single mechanism. Conversely, we propose that they are due to different mechanisms. In particular, a visuo-spatial mechanism is responsible for omissions and a perceptual integration process for substitution errors. We measured the performance of six patients with both neglect and neglect dyslexia, analyzing their reading errors as a function of letter spacing. According to our conjecture, letter spacing should increase omissions by moving part of the string further in the unattended space, while it should reduce substitutions by restoring the integration processes. Furthermore, we predict that letter spacing should be more effective with pseudowords compared to words, in that in this latter case lexical effects are supposed to influence attentional and perceptual processes. Accordingly, we found that for pseudowords only the two types of errors are differently affected by this manipulation and only omissions correlate with the severity of the disorder in visuo-spatial tasks.

A stimulus-centered reading disorder for words and numbers: Is it neglect dyslexia?

A single case, RCG, showing a unilateral reading disorder without unilateral spatial neglect was studied. The disorder was characterized by substitutions of the initial (left) letters of words, nonwords and Arabic numbers, independently of egocentered spatial coordinates. MRI showed a bilateral lesion with the involvement of the splenium. Although, within the framework of the visual word recognition model proposed by Caramazza and Hillis (1990), RCG disorder could be defined as a stimulus-centered neglect dyslexia, we discuss the hypothesis of a dissociation in neural correlates and mechanisms between the syndrome of unilateral spatial neglect and such a unilateral reading disorder.

Line and word bisection in right-brain-damaged patients with left spatial neglect.

Right-brain-damaged patients with left unilateral spatial neglect typically set the mid-point of horizontal lines to the right of the objective center. By contrast, healthy participants exhibit a reversed bias (pseudoneglect). The same effect has been described also when bisecting orthographic strings. In particular, for this latter kind of stimulus, some recent studies have shown that visuo-perceptual characteristics, like stimulus length, may contribute to both the magnitude and the direction bias of the bisection performance (Arduino et al. in Neuropsychologia 48:2140–2146, 2010). Furthermore, word stress was shown to modulate reading performances in both healthy participants, and patients with left spatial neglect and neglect dyslexia (Cubelli and Beschin in Brain Lang 95:319–326, 2005; Rusconi et al. in Neuropsychology 18:135–140, 2004). In Experiment I, 22 right-brain-damaged patients (11 with left visuo-spatial neglect) and 11 matched neurologically unimpaired control participants were asked to set the subjective mid-point of word letter strings, and of lines of comparable length. Most patients exhibited an overall disproportionate rightward bias, sensitive to stimulus length, and similar for words and lines. Importantly, in individual patients, biases differed according to stimulus type (words vs. lines), indicating that at least partly different mechanisms may be involved. In Experiment II, the putative effects on the bisection bias of ortho-phonological information (i.e., word stress endings), arising from the non-neglected right hand side of the stimulus were investigated. The orthographic cue induced a rightward shift of the perceived mid-point in both patients and controls, with short words stressed on the antepenultimate final sequence inducing a smaller rightward deviation with respect to short words stressed on the penultimate final sequence. In conclusion, partly different mechanisms, including both visuo-spatial and lexical factors, may support line and word bisection performance of right-brain-damaged patients with left spatial neglect, and healthy participants.

The Centre Is Not in the Middle: Evidence from Line and Word Bisection.

English and German readers have been shown to mark a position to the left of the true centre as the subjective midpoint in word bisection. This effect resembles a well-known phenomenon observed with the bisection of solid lines (pseudoneglect), although this behavioural similarity does not imply a common origin. The purpose of the present study was twofold: on the one hand, to investigate the perceptual and lexical features that influence the bisection of Italian orthographic strings and, on the other hand, to investigate whether identical or partially independent processing mediate bisection of line and orthographic stimuli. Five experiments were carried out to explore to what extent stimulus type (lines, words, pseudowords, consonant strings, symbols), stimulus length (from 3 to 13 characters), list context (pure and mixed), and written word frequency (high and low) affected the bisection performance. The results showed that list context modulated the processing similarities across different materials and that word frequency failed to influence the magnitude of the bisection bias. More critically, across all five experiments, the results showed different effects for solid lines versus orthographic material. Lines were always bisected to the left, independent of length and list context. By contrast, a crossover effect emerged with orthographic material; for long stimuli (above five letters) the bias was consistently to the left, while short stimuli showed a consistent rightward bias. The results indicate that manual bisection involved partly different cognitive mechanisms during word and line perception and that this may depend on the characteristics of the stimuli (words/discrete vs. lines/continuous).

Neglect dyslexia: a matter of "good looking".

Brain-damaged patients with right-sided unilateral spatial neglect (USN) often make left-sided errors in reading single words or pseudowords (neglect dyslexia, ND). We propose that both left neglect and low fixation accuracy account for reading errors in neglect dyslexia. Eye movements were recorded in USN patients with (ND+) and without (ND-) neglect dyslexia and in a matched control group of right brain-damaged patients without neglect (USN-). Unlike ND- and controls, ND+ patients showed left lateralized omission errors and a distorted eye movement pattern in both a reading aloud task and a non-verbal saccadic task. During reading, the total number of fixations was larger in these patients independent of visual hemispace, and most fixations were inaccurate. Similarly, in the saccadic task only ND+ patients were unable to reach the moving dot. A third experiment addressed the nature of the left lateralization in reading error distribution by simulating neglect dyslexia in ND- patients. ND- and USN- patients had to perform a speeded reading-at-threshold task that did not allow for eye movements. When stimulus exploration was prevented, ND- patients, but not controls, produced a pattern of errors similar to that of ND+ with unlimited exposure time (e.g., left-sided errors). We conclude that neglect dyslexia reading errors may arise in USN patients as a consequence of an additional and independent deficit unrelated to the orthographic material. In particular, the presence of an altered oculo-motor pattern, preventing the automatic execution of the fine saccadic eye movements involved in reading, uncovers, in USN patients, the attentional bias also in reading single centrally presented words.

Bilingual vocabulary size and lexical reading in Italian.

In the present study we investigated how the vocabulary size of English-Italian bilinguals affects reading aloud in Italian (L2) modulating the readers sensitivity to lexical aspects of the language. We divided adult bilinguals in two groups according to their vocabulary size (Larger - LV, and smaller - SV), and compared their naming performance to that of native Italian (NI) readers. In Experiment 1 we investigated the lexicality and word frequency effects in reading aloud. Similarly to NI, both groups of bilinguals showed these effects. In Experiment 2 we investigated stress assignment - which is not predictable by rule - to Italian words. The SV group made more stress errors in reading words with a non-dominant stress pattern compared to the LV group. The results suggest that the size of the readers L2 lexicon affects the probability of correct reading aloud. Overall, the results indicate that proficient adult bilinguals show a similar sensibility to the statistical and distributional properties of the language as compared to Italian monolinguals.