Wernicke’s aphasia (WA), an acquired impairment of language comprehension and word repetition, results from a cerebrovascular accident to the left temporoparietal junction. The disorder has been important to the development of neurobiological models of language, however neuropsychological investigations into the nature of the comprehension impairment have been limited. This thesis presents a series of four experiments, investigating the comprehension impairment in WA. Chapter 3, a behavioural neuropsychological study, investigates existing hypotheses of the comprehension impairment in WA: a phonological breakdown, a semantic breakdown, a dual phonological-semantic breakdown. A case series comparison methodology is utilised. Participants with WA are compared to participants from two other clinical, comprehension impaired groups: semantic dementia and semantic aphasia. Semantic dementia and semantic aphasia provide neuropsychological models of semantic breakdown, affecting semantic representations and semantic control respectively. Individuals with WA showed disrupted non-verbal semantic analysis of a similar magnitude to that in semantic dementia and semantic aphasia and of a qualitatively similar nature to that in semantic aphasia. A significantly greater impairment on assessments which required acoustic-phonological analysis was found for individuals with WA compared to semantic aphasia. Overall a dual breakdown in acoustic-phonological and semantic control best accounted for the comprehension impairment in WA. In Chapter 4, direct evidence was sought for a link between acoustic-phonological non-word analysis and auditory comprehension in WA. A novel test of non-word discrimination was created which was perceptually graded so as to provide a sensitive measure in severely impaired participants. Individuals with WA were significantly impaired at non-word discrimination compared to age and hearing matched control participants who performed at ceiling. The degree of non-word discrimination/acoustic-phonological analysis impairment correlated with auditory comprehension in WA. Chapter 5 investigated the extent to which the established acoustic-phonological impairment in WA was grounded in a more fundamental deficit in non-verbal auditory analysis. The capacity to detect structural changes in non-verbal auditory stimuli was measured. Participants with WA had an impaired capacity to detect differences in all but the most structurally simple auditory stimuli, compared to control participants. The degree of this impairment correlated with the degree of auditory comprehension impairment in the WA group. Chapter 6 revisits the semantic impairment observed in WA. Functional magnetic resonance imaging was used to investigate the residual neural networks recruited by individuals with WA, when performing a semantic animate-inanimate judgment task. Large portions of the inferior and anterior temporal lobes bilaterally were activated, regions remote from the lesion in WA. Age matched control participants recruited similar regions; however the activation in WA participants was significantly stronger. This indicated greater reliance on the residual semantic network in WA in response to damage to posterior temporoparietal semantic regions. The results from this series of studies indicated that the primary deficit in WA is one of impaired acoustic analysis and co-morbid damage to a phonological system. Additional disruption occurs to the semantic control network, which regulates the task directed use of semantic representations. A combination of all three factors accounts for the comprehension impairment in WA and it is the relative contributions of each factor that accounts for behavioural variation between individuals.

Thesis (M.S.)--State University of New York at Binghamton, Department of Psychology, 2009. / Includes bibliographical references.

Though the current understanding of language processing is incomplete, it has been established that the left hemisphere is dominant for language in the majority of the population. Damage to language centers of the brain and to white matter tracts connecting these language centers results in a language deficit known as aphasia. Neuroplasticity in the brain can often compensate for these language deficits by strengthening neuronal connections between the right and left hemisphere, or by enhancing the neuronal connectivity of undamaged areas in the left hemisphere. Thus the brain can compensate for damaged language centers by using alternative cortical areas. These compensatory language areas may be homologous areas of the right hemisphere, or other undamaged portions of the left hemisphere. Various imaging techniques have been used to demonstrate this phenomenon. The current neuroimaging technique known as quantitative electroencephalographic brain imaging allows investigators to evaluate the functional anatomical location of language processing. When this mapping is overlaid on a magnetic resonance image, investigators are able to locate areas in the brain of the participant that are electrically activated during elicited speech tasks. This method was used in a single case study to examine the brain of an individual with a unique traumatic brain injury in which the anterior portion of the individual's left temporal lobe was surgically removed and considerable recovery of language subsequently occurred. The stimulus for the quantitative electroencephalography included identifying syntactically incorrect sentences. Imaging results from the participant with traumatic brain injury were compared to imaging results obtained from an age-matched control. Differences in quantitative electroencephalography between the two participants included a delayed P1-N1-P2 response and an absent P600 in the participant with traumatic brain injury. Behavioral results include an increased number of incorrect responses from the participant with traumatic brain injury as compared to the control participant. These results imply an interesting cortical distribution of language processing that could be further assessed by functional magnetic resonance imaging.

失語症病患(aphasic patients)的研究對於語言的運作機制提供了一些訊息，讓我們能從不同的角度認識大腦的運作。本篇研究的目的在於探討失語症病患的自我修補表現(self-repair performance)，我們利用一套具有五大自我修補項目的分類系統分析病患的表現並將參與研究的四位失語症病人區分為流利型(fluent)以及非流利型(non-fluent)病患，之後再分別將四位病人與其治療師一對一的各別談話錄音、譯寫。在流利型的組別之中，我們收集了207個威尼克病患(Wernicke’s aphasics)的自我修補語料，而在非流利型組別當中，則收集了347個布洛卡病患(Broca’s aphasics)的自我修補語料。 結果顯示，威尼克病患與布洛卡病患在自我修補的整體表現基本上是相似的，也就是說，在這五大項目的自我修補模式中，他們使用每一項的頻率是沒有顯著差異的。因此，我們認為自我修補是一種溝通能力的表現，而這樣的能力並不會受到病人各自的語言缺陷所影響。然而，我們得知兩種類型的病患在自我修補的表現上，依然具有一些細微的不同。威尼克病患使用了較多的填補模式(the completion pattern)，這或許與他們較流暢的表達能力有關係，因為他們能較不費力的把尚未完整說出的詞彙補述完成。布洛卡病患則是使用了較多的取代模式(the substitution pattern)，這或許是因為他們的理解能力較好，幫助他們監控了自己說話裡頭的錯誤並進而修正。 此外，比較中文正常說話者與失語症病患的表現，我們發現每一種自我修補項目被使用的比率亦是相似的。這種情況或許提供了一種證明，表示我們在使用自我修補的模式上，都有一種共同的傾向(universal tendency)。 總結來說，在自我修補的表現上，影響失語症病患的三個可能因素是1、在語言處理過程中的複雜度。2、不同類型病人各自具有的語言缺陷。3、每一種自我修補模式所具有的實用性。 / Studies of aphasic patients provide more information for understanding mechanisms of language processing, since we can know more details of the human brain from a different perspective. The purpose of this study is to investigate self-repair performance of aphasics. A classification system made up of five major categories was adopted to analyze their performance. We divided four patients into fluent and non-fluent groups and collected conversation recordings of these four therapist—patient dyads. In fluent group, 207 self-repairs were recognized in the conversation between therapists and Wernicke’s (fluent) patients. In the non-fluent group, 347 self-repairs were found in the conversation between therapists and Broca’s (non-fluent) patients. Results indicated that the overall self-repair performance of Wernicke’s (fluent) and Broca’s (non-fluent) aphasics was similar. That is, the distribution frequency in the five categories was not significantly different. We therefore suggest that the self-repair performance is a communication-oriented ability, and it is not interfered by specific language deficits. However, there were still subtle differences between the two patient groups. We speculate that the relative higher percentage of the completion pattern in Wernicke’s (fluent) group is due to their rather fluent production ability, since they can fulfill an unfinished word without too much difficulty. On the other hand, Broca’s (non-fluent) patients used more of the substitution pattern. That is, they can detect the problems within their own speech and further correct them. This could be attributed to the self-monitoring ability brought by their better comprehension. In addition, comparing with the studies of Mandarin normal speakers (Chui, 1996; Tseng, 2006), we found that the distribution frequency of each self-repair pattern in aphasic patients was similar with the distribution in normal speakers. This similarity might indicate a universal tendency of the self-repair use. In sum, there are three possible factors affecting the self-repair performance of aphasics, they are the processing difficulty, the linguistic deficits of different patients, and the value of the repair pattern.

La documentation scientifique fait état de la présence, chez l’adulte, de cellules souches et progénitrices neurales (CSPN) endogènes dans les zones sous-ventriculaire et sous-granulaire du cerveau ainsi que dans le gyrus denté de l’hippocampe. De plus, un postulat selon lequel il serait également possible de retrouver ce type de cellules dans la moelle épinière et le néocortex des mammifères adultes a été énoncé. L’encéphalopathie de Wernicke, un trouble neurologique grave toutefois réversible qui entraîne un dysfonctionnement, voire une défaillance du cerveau, est causée principalement par une carence importante en thiamine (CT). Des observations récentes laissent envisager que les facteurs en cause dans la prolifération et la différenciation des CSPN pourraient également jouer un rôle important lors d’un épisode de CT. L’hypothèse, selon laquelle l’identification de nouveaux métabolites entrant dans le mécanisme ou la séquence de réactions se soldant en une CT pourraient en faciliter la compréhension, a été émise au moyen d'une démarche en cours permettant d’établir le profil des modifications métaboliques qui surviennent en de telles situations. Cette approche a été utilisée pour constater les changements métaboliques survenus au niveau du foyer cérébral dans un modèle de rats déficients en thiamine (rats DT), particulièrement au niveau du thalamus et du colliculus inférieur (CI). La greffe de CSPN a quant à elle été envisagée afin d’apporter de nouvelles informations sur la participation des CSPN lors d’un épisode de CT et de déterminer les bénéfices thérapeutiques potentiels offerts par cette intervention. Les sujets de l’étude étaient répartis en quatre groupes expérimentaux : un premier groupe constitué de rats dont la CT était induite par la pyrithiamine (rats DTiP), un deuxième groupe constitué de rats-contrôles nourris ensemble (« pair-fed control rats » ou rats PFC) ainsi que deux groupes de rats ayant subi une greffe de CSPN, soit un groupe de rats DTiP greffés et un dernier groupe constitué de rats-contrôles (rats PFC) greffés. Les échantillons de foyers cérébraux (thalamus et CI) des quatre groupes de rats ont été prélevés et soumis à des analyses métabolomiques non ciblées ainsi qu’à une analyse visuelle par microscopie à balayage électronique (SEM). Une variété de métabolites-clés a été observée chez les groupes de rats déficients en thiamine (rats DTiP) en plus de plusieurs métabolites dont la documentation ne faisait pas mention. On a notamment constaté la présence d’acides biliaires, d’acide cynurénique et d’acide 1,9— diméthylurique dans le thalamus, alors que la présence de taurine et de carnosine a été observée dans le colliculus inférieur. L’étude a de plus démontré une possible implication des CSPN endogènes dans les foyers cérébraux du thalamus et du colliculus inférieur en identifiant les métabolites-clés ciblant les CSPN. Enfin, les analyses par SEM ont montré une amélioration notable des tissus à la suite de la greffe de CSPN. Ces constatations suggèrent que l’utilisation de CSPN pourrait s’avérer une avenue thérapeutique intéressante pour soulager la dégénérescence symptomatique liée à une grave carence en thiamine chez l’humain. / Endogenous neural-stem progenitor cells (NSPC) have been documented to be found in the subventricular and subgranular zones, the dentate gyrus, and suggestions of the possibility of these cells being found in the spinal cord and neocortex in adult mammalian brain have been postulated. Thiamine deficiency (TD) is the major cause of Wernicke's Encephalopathy, a reversible neurological disorder that results in cerebral dysfunction and impairment. Recent evidence suggests factors involved in neural NSPC proliferation and differentiation are involved during TD. By means of a current approach for profiling metabolic changes occurring in focal areas of the TD rat brain, specifically the thalamus and the inferior colliculus (IC), it was hypothesized that new metabolites that might offer a better understanding into the sequel and/or mechanism of TD could be identified. It was also considered that the use of NSPC transplantation could offer new information into the involvement of NSPC and potential therapeutic benefit in TD. Non-targeted metabolomics analysis, fluorescences microscopy, and scanning election microscopy (SEM) analysis visualization was performed on samples of the focal areas (thalamus and IC) of pyrithiamine induced TD rats (PTD), pair-fed controls (PFC) rats, and NSPC transplanted TD and PFC rats. Various key metabolites were identified in rats with TD, including previous undocumented metabolites such as bile acids, kynurenic acid, and 1,9-dimethyluric acid in the thalamus and taurine and carnosine in the IC. The study also demonstrated a possible involvement of endogenous NSPC in focal areas of the thalamus and IC identifying key metabolites targeting NSPC and showed tissue amelioration (observed through SEM) following NSPC transplantation. The findings suggested that NSPC could offer a therapeutic alternative to alleviate some of symptomatic degeneration of TD.

Für die Zuweisung von Genus im Deutschen wurden verschiedene Regeln vorgeschlagen. Genuszuweisung kann beispielsweise auf der Grundlage von Suffixregeln erfolgen. Diesen Regeln zufolge sind Derivations- und Diminutivsuffixe zuverlässige Genusindikatoren. Es finden sich nur wenige Ausnahmen zu diesen Regeln. Andere Nomen hingegen scheinen keine Genustransparenz zu haben. Ziel der durchgeführten Studien ist zu prüfen, inwieweit gesunde sowie aphasische Sprecher von formalen Genusindikatoren profitieren. Die Ergebnisse deuten darauf hin, daß gesunde Sprecher des Deutschen, anders als im Französischen oder Italienischen, in einer Genuszuweisungsaufgabe nicht von der Transparenz der Stimuli profitieren. Es wurden keine Reaktionszeitunterschiede zwischen der transparenten und intransparenten Bedingung gemessen. Aphasische Sprecher hingegen machen in der transparenten Bedingung weniger Fehler bei der Genuszuweisung als in der intransparenten Bedingung. Diese Ergebnisse werden im Kontext aktueller Sprachverarbeitungsmodelle diskutiert. Sie legen nah, daß Genus weder nur lexikalisch gespeichert ist noch ausschließlich auf der Basis von Regeln zugewiesen wird. Es wird angenommen, daß beide Strategien Teil der sprachlichen Kompetenz sind. / Different rules have been proposed for the assignment of gender to nouns in German. For instance, on the basis of derivational or diminutive suffixes gender can be assigned reliably, with only a few exceptions. However, there are several nouns that do not have any formal indication of gender. It was the aim to investigated whether normal and aphasic speakers benefit from formal gender cues. Results indicate that healthy speakers do not profit from gender cues in a gender assignment task. There are no differences in reaction times between the transparent and nontransparent condition. This contradicts findings from languages like French and Italian. However, Broca's and Wernicke's aphasics benefit from gender cues, although they do so in a different way. I interpret these findings within the context of current models of language processing and argue that gender is neither only lexically stored nor exclusively assigned on the basis of assignment rules. Both strategies seem to be part of German speakers' language competence.

正常人的語誤中可以取得在心理語言上何為音韻單位的證據，近來有許多針對失語症的病人語誤的研究，發現失語症病人的語誤也可當做測試語言表徵的重要來源資料。 　　本研究針對失語症病人在聲調方面表現，做聲調錯誤頻率分佈、語境影響錯誤、以及錯誤方向種類之分析 然後將整失語症病人聲調表現的分析跟心理語言學語言產出機制作連結。 　　本研究結果顯示，漢語失語症病人聲調表現上第四生錯誤雖然最多，但第四聲在漢語裡原本出現的頻率就最高，所以第四聲不應被認為對失語症病人最為困難。而第三聲雖然在漢語裡出現頻率最低，卻佔了失語症病人聲調錯誤頻率第二高位，因此我們判斷第三聲對失語症病人來說是最為困難的聲調。第二，我們發現漢語失語症病人聲調錯誤受語境影響比正常人低。第三，漢語失語症病人聲調錯誤裡，語境影響語誤之方向性中，錯誤來源在語誤出現前類型較多。第四，我們發現Dell的連續模型(connectionist model)，可以解釋失語症病人在聲調錯誤類型偏好原因。 / Naturally occurring speech errors have been used as evidence for testing the psychological reality of phonological units. A number of researchers start to look at evidence from aphasic speech for testing linguistic representation so the phenomena of aphasia provide tests of the validity of certain aspects of linguistic theory. 　　In this thesis, tone errors made by aphasics were examined and related overall analyses to psycholinguistic models of speech production. In light of the analysis of tone frequency in Mandarin written texts and oral data and tone errors produced by aphasics, relating issues concerning the research questions we put forward were elucidated. First, it seems that tone 4 is the most problematic tone for the aphasics in terms of error rate since tone 4 occurs the most often in errors. However, tone 4 errors intrinsically will occur more that other three tones because of its highest incidence in Mandarin. Thus, tone 4 may not be taken as the most difficult tone for aphasics merely from its high error rate. Second, the results indicated that non-contextual errors constitute most of the aphasic errors. Third, it has been shown that perseveration is a cross-linguistic feature of aphasia. Fourth, Dell’s connectionist model is proved to be able to account for and make predictions about the error patterns found in both aphasic and normal speech.