Stefania Cerruti

Specific linguistic and pragmatic deficits in Italian patients with schizophrenia

OBJECTIVE Verbal communication impairments are prominent features of schizophrenia. The grammatical and pragmatic components of expressive and receptive verbal abilities were systematically examined, for the first time, in Italian patients with schizophrenia. Indeed, most of the language literature is composed of studies on English speaking people. METHOD Elicited narrative production, and syntactic and pragmatic receptive abilities were analyzed in a cohort of 37 patients with schizophrenia and 37 healthy controls. Furthermore, a conversational speech production task was administered to an age- and gender-matched subset of this population. The level of significance was set at p<or=0.01. RESULTS Participants with schizophrenia produced significantly less words on the narrative task and were less fluent on the conversational task than healthy controls. In both narrative and conversational speech they showed significantly poorer syntactic diversity skills. Errors at word level did not distinguish the two groups. At a receptive level, syntactic abilities were selectively impaired in patients with schizophrenia, who were also slower than controls in providing their answers. Metaphor and idiom explanations revealed consistent deficits in patients with respect to controls. CONCLUSIONS Reduced syntactic diversity characterized expressive language skills in schizophrenia. Syntactic abilities were selectively impaired also at the receptive level, suggesting an underlying processing deficit. On the pragmatic test schizophrenia patients were significantly less able to produce appropriate interpretations, indicating the presence of abnormal pragmatic inferential abilities. These findings confirm that language impairment is a key feature of schizophrenia independent of mother language and suggest a possible deficit involving hemispheric lateralization processes.

Dissimilarity-based detection of schizophrenia

We propose to approach the detection of patients affected by schizophrenia by means of dissimilarity-based classification techniques applied to brain magnetic resonance images. Instead of working with features directly, pairwise distances between expert delineated regions of interest (ROIs) are considered as representations based on which learning and classification can be performed. Experiments were carried out on a set of 64 patients and60 controls and several pairwise dissimilarity measurements have been analyzed. We demonstrate that good results are possible and especially significant improvements can be obtained when combining over different ROIs and different distance measures. The lowest error rate obtained is 0.210.

Shared impairment in associative learning in schizophrenia and bipolar disorder

BACKGROUND Schizophrenia (SCZ) and bipolar disorder (BD) share some cognitive commonalities. However, the role of associative learning, which is a cornerstone of human cognition mainly relying on hippocampus, has been under-investigated. We assessed behavioral performance during associative learning in a group of SCZ, BD and healthy controls (HC). METHODS Nineteen patients with SCZ (36 ± 8.1 years; 13 males, 6 females; all Caucasians), 14 patients with BD (41 ± 9.6 years; 5 males, 9 females; all Caucasians) and 45 HC (27.7 ± 6.9 years; 18 males, 27 females; all Caucasians) were studied. Learning was assessed using an established object-location paired-associative learning paradigm. Subjects learned associations between nine equi-familiar common objects and locations in a nine-location grid. Performance data were analyzed in a repeated measures analysis of variance with time (repeated) and group as factors. RESULTS Learning curves (performance = (1-e(-k x time)) fitted to average performance data in the three groups revealed lower learning rates in SCZ and BD (k = 0.17 and k = 0.34) than HC (k = 0.78). Significant effects of group (F = 11.05, p < 0.001) and time (F = 122.06, p < 0.001) on learning performance were observed. CONCLUSIONS Our study showed that associative learning is impaired in both SCZ and BD, being potentially not affected by medication. Future studies should investigate the neural substrates of learning deficits in SCZ and BD, particularly focusing on hippocampus function and glutamatergic transmission.

Linguistic production and syntactic comprehension in schizophrenia and bipolar disorder

Perlini C, Marini A, Garzitto M, Isola M, Cerruti S, Marinelli V, Rambaldelli G, Ferro A, Tomelleri L, Dusi N, Bellani M, Tansella M, Fabbro F, Brambilla P. Linguistic production and syntactic comprehension in schizophrenia and bipolar disorder.

Laterality effects in schizophrenia and bipolar disorder

There are numerous reports in the literature of lateralised structural cerebral abnormalities and alterations of the corpus callosum in the major psychoses. In the light of these findings the purpose of this study was to directly compare hemispheric differences and callosal interhemispheric transmission (IT) in schizophrenia and bipolar disorder. To do that we tested schizophrenic (SCZ), bipolar disorder (BD) patients and controls in a simple manual reaction time (RT) task with lateralised visual stimuli (Poffenberger paradigm) which enables one to test both laterality effects and IT time. We found an overall slowing of responses with the right hand in schizophrenics but not in bipolar patients, who, like controls, showed no hand differences. This selective slowing down of the right hand is likely to be related to abnormalities of intrahemispheric cortico-cortical connections in the left hemisphere. In contrast, IT time was similar in SCZ and BD patients and did not differ with respect to controls. Two are the novel findings of the present study: first both SZC and BD share a normal IT of visuomotor information despite the presence of callosal abnormalities. Second, an impairment of intrahemispheric left hemispheric processing is present only in SCZ patients. This represents a potentially important clue to a further understanding of the pathogenetic differences between the two major psychoses.

Orbitofrontal cortex abnormalities in schizophrenia.

The magnetic resonance imaging studies investigating the volumes of the orbitofrontal cortex in patients suffering from schizophrenia are here presented, trying to elucidate its role for the pathophysiology and for the cognition of the disease.

Dissimilarity-Based Detection of Schizophrenia

We propose to approach the detection of patients affected by schizophrenia by means of dissimilarity-based classification techniques applied to brain magnetic resonance images. Instead of working with features directly, pairwise distances between expert delineated regions of interest (ROIs) are considered as representations based on which learning and classification can be performed. Experiments were carried out on a set of 64 patients and60 controls and several pairwise dissimilarity measurements have been analyzed. We demonstrate that good results are possible and especially significant improvements can be obtained when combining over different ROIs and different distance measures. The lowest error rate obtained is 0.210.

Multimodal schizophrenia detection by multiclassification analysis

We propose a multiclassification analysis to evaluate the relevance of different factors in schizophrenia detection. Several Magnetic Resonance Imaging (MRI) scans of brains are acquired from two sensors: morphological and diffusion MRI. Moreover, 14 Region Of Interests (ROIs) are available to focus the analysis on specific brain subparts. All information is combined to train three types of classifiers to distinguish between healthy and unhealthy subjects. Our contribution is threefold: (i) the classification accuracy improves when multiple factors are taken into account; (ii) proposed procedure allows the selection of a reduced subset of ROIs, and highlights the synergy between the two modalities; (iii) correlation analysis is performed for every ROI and modality to measure the information overlap using the correlation coefficient in the context of schizophrenia classification. We see that we achieve 85.96 % accuracy when we combine classifiers from both modalities, whereas the highest performance of a single modality is 78.95 %.

P03-104 - Linguistic production and comprehension deficits in schizophrenia and bipolar disorder

Introduction Although language deficits have often been reported in schizophrenia, the specific relevance of single linguistic levels of processing is still under debate. Moreover, little is known about language disturbances in bipolar disorder. Objectives The aims of this study were to: 1) investigate micro-linguistic (lexicon, morphology, syntax) and macro-linguistic (discourse coherence, pragmatics) dimensions of speech production and 2) evaluate syntactic comprehension skills in both schizophrenia and, for the first time, bipolar disorder. Methods A story telling task and a computer-based test of syntactic comprehension were administered to 30 Italian speaking DSM-IV patients suffering from schizophrenia, 30 participants with bipolar disorder and 30 healthy controls, comparable for age and educational level (p>0.05). Analysis of variance with post-hoc correction was performed to compare linguistic performance between groups. Results In comparison to healthy participants, patients with schizophrenia had significantly impaired productivity, syntactic complexity and local/global discourse coherence and bipolar disorder subjects showed deficits in mean length of utterance (p Conclusions Our results showed the presence of both micro and macro-linguistic deficits in linguistic production in schizophrenia, but not in bipolar disorder, suggesting that these abnormalities are specific for schizophrenia. On the contrary, syntactic construction comprehension was altered in both schizophrenia and bipolar disorder, potentially representing the target of innovative rehabilitation strategies.