Leksička obrada kod osobe s Alzheimerovom bolesti

master's thesis

• Title: Leksička obrada kod osobe s Alzheimerovom bolesti : studija slučaja
• Title (english): Lexical processing in a patient with Alzheimer's disease : a case study
• Author: Kornelija Berečić
• Mentor: Jelena Kuvač Kraljević (mentor)
• Mentor: Tatjana Prizl-Jakovac (komentor)
• Committee member: Jelena Kuvač Kraljević (predsjednik povjerenstva)
• Committee member: Tatjana Prizl-Jakovac (član povjerenstva)
• Committee member: Draženka Blaži (član povjerenstva)
• Granter: University of Zagreb; Faculty of Education and Rehabilitation Sciences; Zagreb
• Defense date and country: 2019-09-26, Croatia
• Scientific / art field, discipline and subdiscipline: SOCIAL SCIENCES; Speech Therapy

Abstract

Alzheimerova bolest najčešći je uzročnik neurokognitivnih poremećaja. Simptomi se pojavljuju postupno, tijekom više mjeseci ili godina te variraju u pojavnosti i intenzitetu. Najčešći rani simptom je poremećaj epizodičkog pamćenja, a iznimka su atipične prezentacije bolesti. Jezične teškoće dio su kliničke slike osoba s Alzheimerovom bolesti. Jezični problemi najčešće započnu kao anomička afazija. Napredovanjem bolesti teškoće se proširuju na druge razine jezične obrade i time prelaze u teži stupanj jezičnog poremećaja. Širenje neurodegenerativnih promjena prekida integritet jezičnih neuralnih mreža što narušava leksičku obradu. Proces obrade riječi odvija se brzo i s velikom točnošću, no mehanizam u podlozi je izrazito složen. Leveltov model jezične proizvodnje objašnjava složeni mehanizam u podlozi priziva riječi i pretpostavlja mogućnost nastanka teškoća na trima razinama leksičke obrade – konceptu, lemi ili leksemu. Na priziv riječi utječe i niz psiholingvističkih obilježja.
Oslanjajući se na dio Leveltovog modela jezične proizvodnje koji se odnosi na sam konstrukt riječi, cilj ovog rada je ispitati leksičku obradu na sve tri razine leksičke obrade i utvrditi mjesto gdje je leksička obrada narušena kod ispitanice s Alzheimerovom bolesti. Leksička obrada ispitana je zadatcima koji su oblikovani u svrhu ovog diplomskog rada te određenim zadatcima iz CAT-HR testa. U zadatcima su kontrolirana psiholingvistička obilježja predočivosti, učestalosti i duljine riječi.
Rezultati kvalitativne analize jasno pokazuju da ispitanica ima teškoće na semantičko-sintaktičkoj razini obrade dok je obrada leksema intaktna. Čini se da je leksička obrada na razini leme narušena uslijed nedovoljno snažne aktivacije poslane s konceptualne razine ili zbog narušene organizacije mentalnog leksikona lema, što usporava pristup i pronalaženje odgovarajućih riječi u zadatcima. Narušenost obrade na konceptualnoj razini ne može se potvrditi sa sigurnošću zbog poremećaja vizualnog procesiranja koji je izražen u ove ispitanice. Na manjem broju zadataka koji nisu uključivali vizualnu percepciju, ispitanica nije pokazivala probleme u obradi koncepta.

Abstract (english)

Alzheimer's disease is the most common cause of neurocognitive disorders. The symptoms appear over time, throughout a number of months or years, and vary in their intensity and occurrence. The earliest common symptom is a disturbance in episodic memory with the exception of atypical presentations of the disease. Language impairments are part of the clinical picture of Alzheimer's disease. Language difficulties are first presented as anomic aphasia. As the disease progresses these difficulites appear at other levels of language processing, thereby developing into more severe forms of language disorder. Language processing depends on the integrity of neural networks which becomes disjointed as neurodegenerative changes start to affect a larger area. While lexical processing is very fast and precise, the underlying mechanism is extremely complex. Levelt’s model of speech production explains that underlying mechanism while assuming the possibility of issues arising at three different levels of lexical process – concept, lemma or lexeme. Furthermore, a number of psycholinguistic factors can affect lexical retrieval.
The aim of this thesis is to examine the lexical processing on all three levels, while focusing on the aspect of Levelt’s model of speech production regarding the word itself, and to determine at which point the lexical processing becomes impaired in a participant suffering from Alzheimer’s disease. Lexical processing was examined with different tasks, which were modelled specifically for the purpose of this thesis and a few tasks taken from the CAT-HR test. Three psycholinguistic factors - imageability, frequency and word length, were controlled in these tasks.
Qualitative analysis results clearly indicate the participant has difficulties in processing semantic and syntatic information, while lexeme processing remains intact. There are indications that the lexical process is impaired due to insufficient activation from the conceptual level, or possibly stemming from an impaired mental lexicon which delays access and retrieval of appropriate words during lexical processing. The impairment of processing on conceptual level cannot be fully ascertained as the patient also had difficulties in visual processing. In tasks which did not require visual perception, the patient did not show difficulties in processing conceptual information.

• Keywords: Alzheimerova bolest; leksička obrada; Leveltov model; stečeni jezični poremećaj
• Keywords (english): Alzheimer's disease; lexical processing; Levelt's model; acquired language disorder
• Language: croatian
• URN:NBN: urn:nbn:hr:158:811896
• Study programme: Title: Graduate study of Speech and Language Pathology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra logopedije (magistar/magistra logopedije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2019-11-04 07:26:46