RESUMO
There is evidence that the explicit lexical-semantic processing deficits which characterize aphasia may be observed in the absence of implicit semantic impairment. The aim of this article was to critically review the international literature on lexical-semantic processing in aphasia, as tested through the semantic priming paradigm. Specifically, this review focused on aphasia and lexical-semantic processing, the methodological strengths and weaknesses of the semantic paradigms used, and recent evidence from neuroimaging studies on lexical-semantic processing. Furthermore, evidence on dissociations between implicit and explicit lexical-semantic processing reported in the literature will be discussed and interpreted by referring to functional neuroimaging evidence from healthy populations. There is evidence that semantic priming effects can be found both in fluent and in non-fluent aphasias, and that these effects are related to an extensive network which includes the temporal lobe, the pre-frontal cortex, the left frontal gyrus, the left temporal gyrus and the cingulated cortex.
Assuntos
Afasia/fisiopatologia , Cognição/fisiologia , Potenciais Evocados/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Semântica , Anomia/fisiopatologia , Afasia de Broca/fisiopatologia , Afasia de Wernicke/fisiopatologia , Compreensão/fisiologia , Medicina Baseada em Evidências , Humanos , Imageamento por Ressonância Magnética/métodos , Memória/fisiologia , Tempo de ReaçãoRESUMO
There is evidence that the explicit lexical-semantic processing deficits which characterize aphasia may be observed in the absence of implicit semantic impairment. The aim of this article was to critically review the international literature on lexical-semantic processing in aphasia, as tested through the semantic priming paradigm. Specifically, this review focused on aphasia and lexical-semantic processing, the methodological strengths and weaknesses of the semantic paradigms used, and recent evidence from neuroimaging studies on lexical-semantic processing. Furthermore, evidence on dissociations between implicit and explicit lexical-semantic processing reported in the literature will be discussed and interpreted by referring to functional neuroimaging evidence from healthy populations. There is evidence that semantic priming effects can be found both in fluent and in non-fluent aphasias, and that these effects are related to an extensive network which includes the temporal lobe, the pre-frontal cortex, the left frontal gyrus, the left temporal gyrus and the cingulated cortex.
Há evidências de que os déficits de processamento léxico-semântico explícitos que caracterizam a afasia podem ser observados na ausência de déficits semânticos implícitos. O objetivo deste artigo foi analisar criticamente a literatura internacional sobre processamento léxico-semântico na afasia, avaliado por meio do paradigma de priming semântico. Especificamente, esta revisão teve seu foco na afasia e processamento léxico-semântico, pontos fortes e fracos da metodologia dos paradigmas léxico-semânticos usados, e evidências recentes de estudos de neuroimagem sobre o processamento léxico-semântico. Além disso, evidências de dissociações entre processamento léxico-semântico implícito e explícito relatadas na literatura serão discutidas e interpretadas, relacionando-se aos dados de neuroimagem funcional de amostras saudáveis. Há indícios de que os efeitos de priming semântico podem ser encontrados tanto em afasias fluentes como em não fluentes, e que esses efeitos são relacionados a uma extensa rede que inclui o lobo temporal, o córtex pré-frontal, o giro frontal esquerdo, o giro temporal esquerdo e o córtex cingulado.
Assuntos
Humanos , Afasia/fisiopatologia , Cognição/fisiologia , Potenciais Evocados/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Semântica , Anomia/fisiopatologia , Afasia de Broca/fisiopatologia , Afasia de Wernicke/fisiopatologia , Compreensão/fisiologia , Medicina Baseada em Evidências , Imageamento por Ressonância Magnética/métodos , Memória/fisiologia , Tempo de ReaçãoRESUMO
Williams syndrome (WS) is a neurodevelopmental genetic disorder, often referred as being characterized by dissociation between verbal and non-verbal abilities, although the number of studies disputing this proposal is emerging. Indeed, although they have been traditionally reported as displaying increased speech fluency, this topic has not been fully addressed in research. In previous studies carried out with a small group of individuals with WS, we reported speech breakdowns during conversational and autobiographical narratives suggestive of language difficulties. In the current study, we characterized the speech fluency profile using an ecologically based measure--a narrative task (story generation) was collected from a group of individuals with WS (n = 30) and typically developing group (n = 39) matched in mental age. Oral narratives were elicited using a picture stimulus--the cookie theft picture from Boston Diagnosis Aphasia Test. All narratives were analyzed according to typology and frequency of fluency breakdowns (non-stuttered and stuttered disfluencies). Oral narratives in WS group differed from typically developing group, mainly due to a significant increase in the frequency of disfluencies, particularly in terms of hesitations, repetitions and pauses. This is the first evidence of disfluencies in WS using an ecologically based task (oral narrative task), suggesting that these speech disfluencies may represent a significant marker of language problems in WS.
Assuntos
Afasia de Wernicke/fisiopatologia , Desenvolvimento da Linguagem , Testes de Linguagem , Fala/fisiologia , Síndrome de Williams/fisiopatologia , Adolescente , Adulto , Afasia de Wernicke/diagnóstico , Criança , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/fisiopatologia , Feminino , Humanos , Masculino , Narração , Estimulação Luminosa/métodos , Adulto JovemRESUMO
El paciente afásico comúnmente muestra alteraciones a nivel gestual, observándose diferencias entre afásicos fluentes y no fluentes. Sin embargo, no está claro si la naturaleza del déficit es simbólica o práxica. El presente estudio compara el rendimiento de la pantomima en pacientes afásicos (Broca y Wernicke) según: severidad de afasia, comprensión de la pantomima, apraxia ideomotora y déficit cognitivo. Además, compara el rendimiento entre pacientes y sujetos normales, realizándose un análisis cualitativo de los tipos de errores cometidos por los pacientes. Los resultados muestran que los pacientes afásicos rinden significativamente peor que los normales y que los afásicos de Broca rinden significativamente mejor que los afásicos de Wernicke. Por otra parte, la severidad de afasia correlaciona significativamente con el rendimiento de la pantomima en ambos. La comprensión de la pantomima y la apraxia ideomotora correlacionaron significativamente solo con los afásicos de Wernicke. La respuesta más común en los afásicos de Broca fue la de tipo incompleta y en los afásicos de Wernicke fue la de tipo relacionada.
Assuntos
Humanos , Masculino , Adolescente , Adulto , Feminino , Pessoa de Meia-Idade , Apraxia Ideomotora , Afasia de Broca/fisiopatologia , Afasia de Wernicke/fisiopatologia , Gestos , Atenção/fisiologia , Estudos de Casos e Controles , Comportamento Imitativo/fisiologia , Comunicação não Verbal , Desempenho Psicomotor , Tempo de Reação , Testes NeuropsicológicosRESUMO
This article describes the development of language in a left-handed girl with a left middle cerebral artery infarction. Seven language samples of parent-child interaction, obtained when she was between 36 and 60 months of age, were transcribed and analyzed using the Child Language Data Exchange System. At 36 months of age, only 42 (20%) of the child's 214 utterances contained words; the other 80% were composed of jargon or interactional markers such as "uh-huh" and "uhn-uhn." Jargon incorporated familiar intonational contours and prosodic features to convey emotional states and communicative functions. Between 36 and 45 months of age, her jargon became differentiated into increasing approximations of English sentences. Simultaneously, her use of words and word combinations increased. By 54 months of age, no jargon was heard. The pattern of development observed in this child can be described as a transient jargon or fluent aphasia. It may have resulted from initial reliance on an uninjured right hemisphere. However, given the similarity between this pattern and the expressive or gestalt style of learning seen in some normal children, the pattern may also be related to other variables including characteristics of the parental input.
Assuntos
Afasia de Wernicke/fisiopatologia , Lesões Encefálicas/fisiopatologia , Lateralidade Funcional , Transtornos do Desenvolvimento da Linguagem/diagnóstico , Adulto , Afasia de Wernicke/complicações , Afasia de Wernicke/etiologia , Encéfalo/patologia , Encéfalo/fisiopatologia , Lesões Encefálicas/complicações , Doenças Arteriais Cerebrais/fisiopatologia , Linguagem Infantil , Pré-Escolar , Feminino , Humanos , Transtornos do Desenvolvimento da Linguagem/complicações , Transtornos da Linguagem , Testes de Linguagem , Aprendizagem , Relações Mãe-Filho , Gravidez , Complicações na Gravidez , Tomografia Computadorizada por Raios X , Comportamento Verbal , VocabulárioRESUMO
While a relative preservation of repetition in acute transcortical aphasia (TA) has usually been associated with the functional integrity of the speech dominant (left) perisylvian area, recent amytal data (Bando et al., 1986) have suggested a fundamental role of the nondominant (right) hemisphere in language repetition. The neuroradiological correlates of repetition were studied in a consecutive series of 21 patients with acute TA. A similar frequency of either perisylvian or extraperisylvian pathology was found. In 2 patients with perisylvian pathology, the injection of amytal in the hemisphere contralateral to the lesion abolished repetition. Positron emission tomography (PET) in another patient revealed marked hypometabolism over the entire left cortical mantle ipsilateral to a basal ganglia lesion, suggesting that preserved repetition was carried out by right hemisphere structures. This was confirmed in a second patient with left extraperisylvian pathology, in whom a second lesion in the right hemisphere resulted in impaired repetition. These findings suggest that the spared contralateral hemisphere may subserve residual repetition in some transcortical aphasic patients with a lesion within or outside the speech-dominant perisylvian area.