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Background: Language disorder in schizophrenia is explained by a theory that attributes language abnormalities to abnormalities in the structure and function of semantic memory, which in turn lead to the language abnormalities. The aim of this study was to examine the role of psycholinguistics parameters in lexical-semantic processing of early-course psychosis. Methods: The study included twenty patients who were undergoing a treatment and diagnostic differentiation within early-course psychosis. The control group was matched with the patients in age and sex. The subjects performed four experiments: an explicit semantic matching task, lexical- semantic decision task, elicited-association production test and a forced- choice comprehension test. The experiments measured time and accuracy of lexical-semantic processing. The stimuli were presented visually on a computer screen and were consistently balanced, from the psycholinguistic database Psiholeks_HR. In the database, each of the words is also attributed with the measures and values of the five psycholinguistic parameters: subjective word frequency, imageability, abstractness/concreteness, word familiarity and age of acquisition and word associations. Results: In a semantic matching task, the patient group had lower accuracy and longer reaction times compared with healthy subjects, as well as better accuracy for related word- pairs and longer reaction times for unrelated word-pairs. The lexical-semantic relatedness effect supposes different activation in the semantic memory of related versus unrelated word-pairs. Semantically related pairs are considered to result in a larger spread of activation, as the activation of concept nodes is dependent on shared lexical-semantic features of concepts. The increased activation of concepts in the semantic memory of individuals with schizophrenia is found to be faster spreading and lacking in inhibition in relation to healthy control subjects. In a lexical-semantic decision task, the patient group was significantly less accurate on the taxonomy condition than the control group. The higher activation of shared features in animate concepts demanded heightened inhibition, which failed and resulted in the activation of incorrect relations in the semantic memory and lower accuracy in the patient group. Furthermore, when shared features were not activated, there were no differences in accuracy between the two groups. In elicited- association production test the patient group had longer reaction times on both imageability conditions in relation to the control group. While the control group had shorter reaction times on highly imageable words, the patient group’s reaction times did not differ on account of the imageability condition. In the forced-choice comprehension test the patient group had overall longer reaction times independently of the imageability condition. Both groups statistically more often chose associations that were of high and medium frequency, when compared to low frequency words, and the target group had longer reaction times on high- and medium-frequency words than on low-frequency words. Discussion: In clinical practice, the determination of language classifiers for early-course psychosis could potentially enable the creation of reliable diagnostic markers and instruments for identifying the population with an elevated risk of developing psychotic disorders in schizophrenia spectrum, and predicting the course of the disorder.

We firstly introduce the notion of lexical- semantic deficits in schizophrenia and the concept of semantic fluency. We follow with a review of semantic fluency studies in schizophrenia patients. Thereafter, we present the results of two studies from our lab. In a study of semantic fluency in first-episode psychosis with schizophrenia features/symptoms, we found disproportionate deficits across different lexical-semantic categories in the patient group. In another study of on the neuropsychological background of verbal fluency in healthy Croatian speakers, we found that animal fluency is highly correlated with visual object recognition, while tree fluency is also highly correlated with cognitive flexibility and visual episodic memory.

Background It is widely assumed that lexical-semantic deficits in first-episode psychosis occur as a syndrome of a dysfunctional neural connectivity and global functional changes in brain regions that are crucial for language processing because of a broadly distributed network disorder. Purpose The aim of this study was to investigate deficits of mental lexicon access in psychosis. Furthermore, the question that has arisen is the role of lexical-semantic features of animacy in lexical-semantic processing in regard to executive functions. Concepts that share the animacy feature also suppose more correlated intercategory features. On the other hand, inanimate concepts have more distinctive features. Furthermore, the correlation of intercategory features increases the automation of connections in the mental lexicon and presupposes activation of a higher number of clusters. Method Specific aspects of lexical-semantic processing were tested in The University Psychiatric Hospital Vrapče on 30 patients with diagnosed first-episode psychosis who were matched with a control group consisting of 30 healthy participants.Analysis confirmed that there are differences in clustering and switching strategies between the patients and the control group. Results The results of this study have demonstrated that patients have fewer automated links in all tested lexical-semantic categories, but the animate category features are shown to be most preserved. On account of these results we can assume that different lexical-semantic categories produce a neural noise of different intensity. Conclusions The contribution of this study is in line with determining language classifiers which could help in additional diagnosing of the acute disorder and could potentially enable the prediction of the course of the disorder and its functional outcome.

Focus of this study was to review which aspects of working memory, and to what extent, are associated with verbal fluency. It is generally believed that working memory consists of the phonological loop, the visuospatial sketchpad and the central executive. The aim of this study was to examine the interaction of the visuospatial sketchpad and central executive with semantic and phonemic fluency. Our research hypotheses were (1) there will be a positive correlation between the visuospatial sketchpad and semantic fluency, (2) the correlation effect sizes will differ depending on semantic category and (3) there will be a positive correlation between the central executive and both fluency tasks. The visuospatial sketchpad was assessed with the Spatial Working Memory test, and the central executive with the Attention Switching Task (both tests are part of the CANTAB test battery). The study included 20 participants, ranging from 18 to 30 years of age. According to Levelt et al. (1999) lexical access is the ability to retrieve grammatical representations and sound forms of words from the mental lexicon, and the executive control ability controls and regulates thought and direct behavior toward a general goal. Furthermore, in performing the semantic fluency task, a validated tool for lexical access assessment, participants rely on existing links between concepts or words in word retrieval (e.g., cat) and can automatically activate semantically associated words (e.g., dog, tiger), while in performing the phonemic fluency task such associations need to be inhibited. In accordance with Levet’s model, the results of this study suggest that the central executive functions may play a great role in the performance of both fluency tasks, and that the visuospatial component has an important role only in semantic fluency. Therefore, differences in the two fluencies likely depend on different mechanisms of the mental lexicon.

Introduction: Language disturbances, usually seen as loosening of associations, have featured prominently among „characteristic" signs and symptoms of schizophrenia from the earliest conceptualizations. There is an open question of the nature of language disturbances, as indicators of underlying cognitive disturbances or core symptoms of the disorder. Aims: The aim of the collaboration between University of Zagreb linguists and psychiatrists was to describe lexical-semantic deficits in schizophrenia-spectrum disorders and to determine correlations between executive functions and lexical-semantic deficits. Finally, the aim was to link these changes with specific symptom clusters and evaluate their possible value in indicating/predicting particular illness phases/courses. Participants and methods: First-episode psychosis (FEP) patients and those early in the course of schizophrenia-spectrum psychotic disorder will be recruited and evaluated clinically to determine symptom clusters profile/severity. Earlier collaboration focused on verbal fluency task and categorization, while in the present study participants were tested on both lexical- semantic processing as well as cognitive functioning. Psycholinguistic tests were developed to determine different aspects of lexical-semantic deficits. Results: Comparison of FEP and healthy individuals showed deficits in hypernymy/ hyponymy processing and the processing of semantic-pragmatic structures, in both production and reception. Results also confirm previous research with regards to significant differences in clustering mechanisms in verbal fluency tasks and relativity of lexical-semantic category boundaries. Additionally, we found that neural noise during lexical recall in FEP depends on the given lexical-semantic category. Data collection is ongoing in the current project on psycholinguistic parameters in lexical-semantic deficits. Conclusion: There are clear changes in lexical-semantic processing in FEP patients. Clinical linguistics creates an arena for multidisciplinary efforts of linguists and psychiatrists (but related fields as well) in an attempt to elucidate processes underlying schizophrenia-spectrum disorders and potentially come up with new diagnostic/prognostic instruments.

Lexical-semantic deficits in first-episode psychosis have been relatively explored, but few questions remain answered. The aim of this study was to investigate the preservation of category relations in the mental lexicon of first-episode psychosis patients with schizophrenic symptoms or symptoms similar to schizophrenia. The study recruited 24 first- episode psychosis patients from the University Psychiatric Hospital “Vrapče” in Zagreb and 24 matched control subjects. Subjects performed a lexical-semantic categorization task where they had to determine which of the four possible answers was a hyponym of the given lexical- semantic category. The task consisted of 10 categories, and each category was tested using 5 different exemplar hyperonyms. Other than the target word, three distractors were presented: a semantical-pragmatically related distractor, meronym and lexical-semantically unrelated word. Research was guided by two hypotheses: (1) the patient group would show significantly less correct answers compared to the control group, and (2) the patients would choose significantly more semantical- pragmatically related distractors, but not other distractors. Our hypotheses were modeled after the recent findings of Berberian et al. (2016) and Gabrić et al. (in press) who suggest stronger neural noise during lexical-semantic processing and a dysfunction of automated connections in the mental lexicon of first- episode psychosis and schizophrenia patients due to deficits in executive functioning. Both hypotheses were confirmed. Our results support the hypothesis that there is no significant damage to the mental lexicon in first-episode psychosis and that lexical-semantical deficits can be attributed to stronger neural noise in the mental lexicon of patients. This further implies that lexical-semantic deficits in first-episode psychosis are largely due to deficits in executive functioning and specifically inhibition. In addition, our results suggest that stronger neural noise in first-episode psychosis causes an outward shift of lexical-semantic category boundaries, but doesn’t include meronyms and semantically unrelated words.

Predstavljanje projekta Klinička lingvistika: psiholingvistički parametri u leksičko- semantičkoj obradi i izvršnim funkcijama kod osoba oboljelih od shizofrenije

Hemispheric lateralization of concrete and abstract words in medial temporal lobe epilepsy

PALPA (Psycholinguistic Assessments of Language Processing in Aphasia ; Kay et al. 1992) battery of tests was translated and adapted to Croatian (Erdeljac et al. 2014 ; Peti-Stantić et al. 2014) and a group of aphasics was tested in order to assess the hypothesized difference in accuracy modulated by the feature of imageability (HI for High Imageable and LI for Low Imageable ; cf. Gvion and Friedman 2013 ; Dual-Coding Theory: Paivio 1990, 2010 ; Holcomb et al. 1999 ; Kounios and Holcomb 1994 ; West and Holcomb 2000 ; Sabsevitz et al. 2005). We further explored the relation of verbal and nonverbal cognition. Our hypothesis is that bimodal presentation of stimuli, and the complexity of performed cognitive and lexical tasks influence the accuracy of lexical choices in the aphasic group. Our research was conducted based on three tests from PALPA battery designed to examine lexical processing - in binary matching condition and in forced task word-picture and only language-mediated condition. The study included 30 participants with different types of fluent and non-fluent aphasia and 30 paired healthy participants, all native speakers of Croatian. We specifically report results of 11 Broca’s aphasics. They scored significantly lower than other aphasics (including anomic aphasics) and healthy participants on all tests and exhibited by far the greatest variation across subjects. The difference between Broca’s and anomic aphasics did not reach significance for tests of lower complexity (47 and 48), but was highly significant for complex tests (0.0002 for HI and LI), irrespective of the modality. Standard reports on types of deficits limited to syntactic processing demonstrated by Broca’s aphasics already established that they perform poorly on certain syntactic tasks, especially ones in which they have to rely only on syntax and cannot use contextual information to arrive at the understanding. This holds for English and crosslinguistically (Caplan and Futter 1986 ; Caplan et al. 2007, 2013 ; Bates et al. 1991 ; Lukatela et al. 1988, 1995). However, Broca’s patients are rarely tested on lexical decision tasks. By comaring our data to data from syntactic processing studies, we conclude that divergence of Broca’s aphasics in processing lexical tasks of different complexity from other groups tested is due to the weight and stability of disruptions in the process and not due to knowledge type. Such findings, coupled with more controlled psycholinguistic studies, should enable us to redefine Broca’s aphasics deficits. Since the data suggest that syntax and lexicon are equally disrupted, our tentative claim is that the deficit Broca’s aphasics suffer from lies in the domain of complexity and is not specifically pertinent to the syntax. Concerning the other condition, undoubtedly we need a systematic series of comparisons in order to distinguish between pure linguistic, language-mediated and visual tasks. We present the setup of controlled RT studies for an ordered set of non-linguistic and linguistic tasks that overlap in sensorimotor and semantic domains, closely matched on all procedural dimensions and timing dimensions. The present study did not comprise such a match because we decided to start with an established testing battery designed both for diagnostics and research (Bate et al. 2010 ; Kay et al. 2010). It turned out that the PALPA battery calls for significant improvements in order to become truly suitable for psycholinguistic experimentation.

According to Trebuchon-Da Fonseca et al (2009), patients with left temporal lobe epilepsy are less successful in lexical processing in comparison to patients with right temporal lobe epilepsy. Epilepsy causes functional differentiation between the anterior temporal lobe structures involved in semantic processing and the neocortical posterior structures involved in lexical processing. The aim of this research is to examine the differences in semantic processing of concrete and abstract words in the Croatian language in patients with lateral temporal lobe epilepsy when compared to healthy subjects on the basis of a quantitative and qualitative analysis. Semantic processing of the aforementioned two groups of words is expected to be less successful in patients with lateral temporal lobe epilepsy than in healthy subjects and differences in lateralization with respect to the focal point are expected as well, i.e. a focal point in the left hemisphere is expected to be found in patients with more severe and specific semantic impairments.

Imageability has been argued to induce asymmetry in processing of nominal lexical units as this feature of the mental lexicon unit is sensitive to the stimulus modality and to the conceptual system. Double modality of the representation of concrete nouns in the mental lexicon, verbal and non-verbal representation, contrasted with single, verbal, representation in abstract nouns [Paivio] is argued to facilitate the processing of a concrete noun and slow down successful retrieval, access and any further processing of an abstract noun [Sabsevitz et al.]. However, research confirming double dissociation of imageability underlines the claim that for the account of imageability it is equally crucial to verify the processing capacity of the mental lexicon’s interface with the conceptual system [Gvion & Friedmann]. The first aim of the study is to investigate whether is a significant difference in the semantic processing of high and low imageable words in people with aphasia compared to the healthy control speakers when presented with a visual or auditive stimulus. The second aim of the study is to investigate whether the greater asymmetry in semantic processing of high and low imageable words stems from the incoming stimulus modality that is impaired in aphasic people, or to the interface processing capacity of the mental lexicon with the conceptual system. Research was conducted based on the three tests designed to examine the processing of the lexical feature of imageability: Auditory Synonym Judgements, Written Synonym Judgements and Word Semantic Association from the battery of tests PALPA adapted for Croatian [Kay et al., Erdeljac et al.]. To reduce the effect of perceptive impairments, general semantic processing was verified by conducting two follow-up PALPA comprehension tests: Spoken Word-Picture Matching and Written Word-Picture Matching. The study included 30 participants with different type of aphasia (motor, sensory, and global) and 30 paired healthy participants ; all native speakers of Croatian. In line with the predictions, there was a statistically significant difference between experimental and control group ; the experimental group further confirmed the predictions by achieving significantly lower results with respect to low- imageable words. Difficulties in recognition of low imageable words in aphasics confirm the existing variations in the organization of processing pathways as imagined by Modular Models depicted in PALPA. These variations also correlate with the interaction of stimulus modality and facilitating effects due to representation modality as predicted by Dual-Coding Theory. Double-dissociation with respect to mental lexicon’s interface to conceptual system is further discussed based on the results of the two comprehension tests. Selected references: Gvion, A. & N. Friedmann (2013) A selective deficit in imageable concepts: a window to the organization of the conceptual system ; Frontiers in human neuroscience ; 7 ; 1-13. Kay, J. et al. (1992). Psycholinguistic Assessment of Language Processing in Aphasia (PALPA). London: Lawrence Erlbaum Associates. Paivio, Allan (2010) Dual coding theory and the mental lexicon ; The Mental Lexicon ; 5 (2) ; 205–230. Sabsevitz, D. S. et al. (2005) Modulation of semantic system by word imageability ; NeuroImage ; 27 ; 188–200. Erdeljac et al. (submitted) Lexical Feature of Imageability in the Mental Lexicon of People with Aphasia. Govor/Speech.

Semantic processing in aphasia is commonly assumed to be affected by a specific language impairment. According and to modular models (MM), this is due to the impairment of a specific module or pathway, and according to Du- Neuro- linguistics al-code theory (DCT), the impairment is relative to a specific modality of mental representation. In this paper, we examine the extent to which the modality of stimuli facilitates recognition of high-low imaginable nouns in varying types of aphasia and reconsider relevance of integrating semantic category of imageability into current models of semantic processing and mental lexicon. To verify the hypothesis that each type of aphasia can provide a pathway specific evidence for DCT, we tested 24 Croatian aphasic patients on the adapted version of Picture and Word Semantics battery of tests from PALPA: Psycholinguistic Assessments of Language Processing in Aphasia. Experiment results differentiated between 3 ty- pes of aphasia (sensory, nominal and motor). Collected data was used to conduct two follow up studies. First study concentrated on stimulus modality and check for the facilitating effects picture of high imaginable nouns has on semantic processing in 3 types of aphasia. This study analysed data collected on Spoken and Written Word-Picture Matching and Picture Naming tests. Second study focused on semantic category of imaginability and compared the effect spoken and written stimuli have in semantic processing of high and low imaginable nouns with respect to 3 types of aphasia. This study included data collected on Auditory and Written Synonymy judgment tests. Results allowed us to confirm the existing variations in the organisation of processing pathways specific to each type of aphasia as imagined by MM, and to correlate these variations with the interaction of the stimulus modality and the facilitating effects as predicted by DCT.

Semantic processing in people with nominal and motor aphasia associated with different stimuli: picture, written or spoken word

Poster prezentacija s podacima o pilot- istraživanju semantičke obrade predočivosti u razumijevanju riječi kod osoba s afazijom.

Ispitivan je odnos sintakičko-semantičkih kategorija sinonimije, antonimije, hiperonimije te kolokocije i koordinacije u odgovorima afazičara na usmeno postavljena pitanja.

The text examines the relative values of the syntactic - semantic relationships in the mental lexicon of aphasic patients.

The paper addresses two issues related to the spoken word recognition: the relationship between the amount of acoustic material and the degree of recognizability at the lexical and phonemic levels; and the influence of segmentation ambiguities on the speed and success of the recognition process. The analyses were done on Croatian language material, using the gating paradigm. The results indicate that the degree of recognizability is directly proportional to the signal duration, and inversely proportional to the complexity of segmentation. A combination of bottom-up and top-down processing is involved in successful word recognition.

Interdisciplinary Linguistic and Psychiatric Research on Language Disorders is a collection of scientific papers presented at the International Scientific Workshop on Clinical Linguistics, held on 20 November 2018 at the Education Centre of the University Psychiatric Hospital Vrapce.The Erdeljac & Sekulic Sovic research group in clinical linguistics, based at the Department of Linguistics, Faculty of Humanities and Social Sciences, University of Zagreb, in collaboration with psychiatrists from the Department of Biological Psychiatry and Psychogeriatrics and the Department of Diagnostics and Intensive Care, both at the University Psychiatric Hospital Vrapce, present a unique example of an academic publication designed to spotlight ongoing research on semantic processing in individuals diagnosed with psychosis spectrum disorders who are native speakers of Croatian.A further value of this book lies in the co-authors’ contributions, written by specialists in clinical linguistics and psychiatry to expand the focus of research in clinical linguistics to other domains of language disorders while showcasing the research being undertaken at prominent institutions such as University College London, the University of Cologne, Johannes Gutenberg University Mainz, Philipps University Marburg, the University of Belgrade, the University of Novi Sad, and Massachusetts Institute of Technology.Jana Willer GoldUniversity College LondonEditor-in-chief Objavljivanje ove knjige potpomognuto je sredstvima projekta Clinical linguistics: Psycholinguistic parameters in lexical-semantic processingin patients with schizophrenia i sredstvima Klinike za psihijatriju Vrapce.