Enrico Ripamonti

The anatomical foundations of acquired reading disorders: a neuropsychological verification of the dual-route model of reading.

In this study we investigated the neural correlates of acquired reading disorders through an anatomo-correlative procedure of the lesions of 59 focal brain damaged patients suffering from acquired surface, phonological, deep, undifferentiated dyslexia and pure alexia. Two reading tasks, one of words and nonwords and one of words with unpredictable stress position, were used for this study. We found that surface dyslexia was predominantly associated with left temporal lesions, while in phonological dyslexia the lesions overlapped in the left insula and the left inferior frontal gyrus (pars opercularis) and that pure alexia was associated with lesions in the left fusiform gyrus. A number of areas and white matter tracts, which seemed to involve processing along both the lexical and the sublexical routes, were identified for undifferentiated dyslexia. Two cases of deep dyslexia with relatively dissimilar anatomical correlates were studied, one compatible with Colthearts right-hemisphere hypothesis (1980) whereas the other could be interpreted in the context of Morton and Pattersons (1980), multiply-damaged left-hemisphere hypothesis. In brief, the results of this study are only partially consistent with the current state of the art, and propose new and stimulating challenges; indeed, based on these results we suggest that different types of acquired dyslexia may ensue after different cortical damage, but white matter disconnection may play a crucial role in some cases.

Assessing the inter-rater agreement for ordinal data through weighted indexes

Assessing the inter-rater agreement between observers, in the case of ordinal variables, is an important issue in both the statistical theory and biomedical applications. Typically, this problem has been dealt with the use of Cohen’s weighted kappa, which is a modification of the original kappa statistic, proposed for nominal variables in the case of two observers. Fleiss (1971) put forth a generalization of kappa in the case of multiple observers, but both Cohen’s and Fleiss’ kappa could have a paradoxical behavior, which may lead to a difficult interpretation of their magnitude. In this paper, a modification of Fleiss’ kappa, not affected by paradoxes, is proposed, and subsequently generalized to the case of ordinal variables. Monte Carlo simulations are used both to testing statistical hypotheses and to calculating percentile and bootstrap-t confidence intervals based on this statistic. The normal asymptotic distribution of the proposed statistic is demonstrated. Our results are applied to the classical Holmquist et al.’s (1967) dataset on the classification, by multiple observers, of carcinoma in situ of the uterine cervix. Finally, we generalize the use of s* to a bivariate case.

Contemporary Frequentist Views of the

The 2 × 2 table is the simplest of data structures yet it is of immense practical importance. It is also just complex enough to provide a theoretical testing ground for general frequentist methods. Yet after 70 years of debate, its correct analysis is still not settled. Rather than recount the entire history, our review is motivated by contemporary developments in likelihood and testing theory as well as computational advances. We will look at both conditional and unconditional tests. Within the conditional framework, we explain the relationship of Fisher’s test with variants such as mid-p and Liebermeister’s test, as well as modern developments in likelihood theory, such as p ∗ and approximate conditioning. Within an unconditional framework, we consider four modern methods of correcting approximate tests to properly control size by accounting for the unknown value of the nuisance parameter: maximisation (M), partial maximisation (B), estimation (E) and estimation followed by maximisation (E+M). Under the conditional model, we recommend Fisher’s test. For the unconditional model, amongst standard approximate methods, Liebermeister’s tests come closest to controlling size. However, our best recommendation is the E procedure applied to the signed root likelihood statistic, as this performs very well in terms of size and power and is easily computed. We support our assertions with a numerical study.

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Imitation is a sensorimotor process whereby the visual information present in the models movement has to be coupled with the activation of the motor system in the observer. This also implies that greater the similarity between the seen and the produced movement, the easier it will be to execute the movement, a process also known as ideomotor compatibility. Two components can influence the degree of similarity between two movements: the anatomical and the spatial component. The anatomical component is present when the model and imitator move the same body part (e.g., the right hand) while the spatial component is present when the movement of the model and that of the imitator occur at the same spatial position. Imitation can be achieved by relying on both components, but typically the models and imitators movements are matched either anatomically or spatially. The aim of this study was to ascertain the contribution of the left and right hemisphere to the imitation accomplished either with anatomical or spatial matching (or with both). Patients with unilateral left and right brain damage performed an ideomotor task and a gesture imitation task. Lesions in the left and right hemispheres gave rise to different performance deficits. Patients with lesions in the left hemisphere showed impaired imitation when anatomical matching was required, and patients with lesions in the right hemisphere showed impaired imitation when spatial matching was required. Lesion analysis further revealed a differential involvement of left and right hemispheric regions, such as the parietal opercula, in supporting imitation in the ideomotor task. Similarly, gesture imitation seemed to rely on different regions in the left and right hemisphere, such as parietal regions in the left hemisphere and premotor, somatosensory and subcortical regions in the right hemisphere.

Binomial Trial

Abstract In this paper we apply the s* statistic, aimed to measure the inter-rater agreement between observers in case of ordinal variables, to the evaluation of the quality of University courses. The objective is to measure the inter-rater agreement between students, along with their satisfaction, in order to verify the consistency of judgments expressed by independent observers. s* is a modification of a previously proposed index, which avoids the problem of paradoxes of Cohens and Fleiss’ kappa statistics. We present the s* index from both a descriptive and an inferential point of view. In particular, as far as statistical inference is concerned, we show that s* is a biased estimator of the inter-rater agreement in the population and, under the null hypothesis of inter-rater agreement by chance, s* is asymptotically normally distributed.

Anatomical and spatial matching in imitation: Evidence from left and right brain-damaged patients.

Letter-by-letter (LBL) dyslexia is a reading impairment caused by left occipital damage and characterized by significant increase in reading time according to the number of letters in a given string (word length effect). In analogy to Dejerine’s interpretation of pure alexia (1892), this disorder is said to be the consequence of a disconnection of the word-blind right hemisphere (RH) from the left hemisphere (LH) word recognition system (angular gyrus). However, several patients have been found to maintain some reading capacities. Coslett & Saffran (1989) described four LBL patients who performed better than chance either on lexical decision or on semantic judgment tasks with words that could not be explicitly identified (implicit reading). Results are controversial (Behrmann, Black & Bub, 1990) and not consistent with the assumption of a complete RH blindness. Data on pure alexia and LBL reading were mostly obtained on Frenchor English-speaking patients, i.e. patients speaking languages with largely irregular orthography, but similar results were also occasionally reported for languages with shallow orthography, like Italian (Perri, Bartolomeo, & Silveri, 1996). The purpose of the present study is to collect data on the nature of the implicit reading phenomenon, to analyze the explicit and implicit reading abilities of a bilingual English and Italian-speaking patient suffering from LBL dyslexia, and to verify for a possible different reading behavior in the two languages.

A Measure of Ordinal Concordance for the Evaluation of University Courses

The word superiority effect (WSE) denotes better recognition of a letter embedded in a word rather than in a pseudoword. Along with WSE, also a pseudoword superiority effect (PSE) has been described: It is easier to recognise a letter in a legal pseudoword than in an unpronounceable nonword. At the current state of the art, both WSE and PSE have been mainly tested with English speakers. This study uses the Reicher–Wheeler paradigm with native speakers of Italian (a shallow orthography language). Different from English and French, we found WSE for reaction times (RTs) only, whereas PSE was significant for both accuracy and RTs. This finding indicates that in the Reicher–Wheeler task, readers of a shallow orthography language can effectively rely on both the lexical and the sublexical routes. As to the effect of letter position, a clear advantage for the first-letter position emerged, a finding suggesting a fine-grained processing of the letter strings with coding of letter position and indicating the role of visual acuity and crowding factors.

Lexical and semantic access in letter-by-letter dyslexia: A case report

ABSTRACT Phonological and articulatory programming impairments may co‐occur in aphasic patients and previous research does not offer a clear‐cut picture of their anatomical counterparts. Hickok and Poeppel (2007) put forward a seminal model of speech processes. The ventral stream (mostly bilateral) would be involved in speech recognition and phonological‐lexical processing, whereas the dorsal stream (largely lateralized to the left hemisphere) would map phonological representations onto articulatory motor patterns. In this study we analyzed repetition errors for single words and spontaneous speech ratings on the Italian version of the Aachen Aphasia Test. Through a VLSM procedure we aimed at discriminating the neuroanatomical substrates of the phonological and articulatory impairment (and of their normal functional processing). We also estimated functional connectivity networks related to articulation and phonology using seed‐to‐voxel connectivity analysis with resting state fMRI data. Results indicate that repetition deficit of single words is associated with lesions in a network of left perisylvian areas including the central operculum, the Heschls gyrus, the angular gyrus, and the supramarginal gyrus (posterior part). Articulatory impairment is associated with lesions in a number of areas in the left dorsal stream, such as the insula (anterior portion), the pars opercularis of the inferior frontal gyrus, the central operculum and the precentral gyrus. On the contrary, phonological impairment is underpinned by lesions of the Heschls gyrus, and of the posterior portion of the superior temporal and supramarginal gyri. Anatomo‐clinical correlative results partly support Hickok and Poeppels functional model of phonological and articulatory processing. HIGHLIGHTSWe used an anatomo‐correlative procedure to disentangle the neuroanatomical foundation of phonological and articulatory damage in aphasia.We analyzed repetition errors for single words and spontaneous speech samples using VLSM.VLSM results partly support Hickok and Poeppels functional model of phonological and articulatory processing

Word and Pseudoword Superiority Effects: Evidence From a Shallow Orthography Language

Background: Intuitionistic fuzzy sets (IFS) represent a methodology for quantifying latent variables in questionnaire analysis through membership and non-membership functions, which are linked by an uncertainty function. Objectives: We aim to apply an IFS approach to the problem of students’ satisfaction of university teaching. Such framework can take into account a source of uncertainty related to items and another related to subjects. Results: A new technique for IFS analysis is set forth and generalized to a multivariate scenario. Potential advantages of the IFS perspective with respect to other nonfuzzy approaches are provided. Application: We apply this method to a national program of university courses evaluation and we focus, in particular, on the outcomes of two Masters in Statistics.

Disentangling phonological and articulatory processing: A neuroanatomical study in aphasia

ABSTRACT Background: Reading impairment is frequently associated with neurodegenerative diseases, such as Alzheimer disease (AD), primary progressive aphasia (PPA), and posterior cortical atrophy (PCA). Notwithstanding the clinical relevance of reading processes in these conditions, only a relatively small number of studies have been published on this topic so far. Aims: We investigated the reading impairment in patients with different types of neurodegenerative diseases. In the light of the marked variability in pathological changes affecting brain areas potentially relevant to reading, it could be hypothesised that these neurodegenerative conditions may lead to different patterns of reading impairment. Methods & Procedures: Three groups of patients (AD, PPA, and PCA) and a control sample of neurologically healthy participants were examined with five tasks to test the ability to read and to repeat words and nonwords, as well as with an auditory and visual lexical decision task. Outcomes & Results: No specific pattern emerged as strongly diagnostic of a specific degenerative disease. Overall, AD and PPA patients were significantly more impaired in reading nonwords than words. Lexical decision impairment in the visual modality appears to be related to PCA, while a similar deficit in the auditory modality is more suggestive of AD. A multiple single-case analysis on the reading performance was run to identify the distribution of different kinds of dyslexia: phonological dyslexia occurred in 50% of patients affected by PCA: it occurred less often in patients affected by AD (15.8%) and PPA (16.7%). Surface dyslexia occurred only in one case of AD. Age of acquisition was predictive of the reading performance for AD patients, but not for PCA and PPA patients. Conclusions: Phonological dyslexia predominates in PCA. Surface dyslexia occurred only in one AD patient. Reading nonwords was predominantly impaired in AD and PPA cases. Impairment in visual lexical decision was associated with PCA, whereas a lexical decision deficit in the auditory modality emerged in AD. Data indicate the importance of extensive testing of reading and input lexical abilities in neurodegenerative diseases.