Lexical competition for production in a case of nonfluent aphasia: Converging evidence from four different tasks

Abstract

We report an individual with Broca's aphasia (J.H.M.), who exhibited powerful lexical context effects in word production tasks. In an adjective-noun production task (Experiment 1), J.H.M.'s production accuracy decreased as the number of adjectives in the phrase increased (e.g., curly hair vs. long curly hair). In a picture pair naming task (Experiment 2), J.H.M.'s naming accuracy was high, but her naming latencies were abnormally delayed when pairs were semantically related (e.g., goat and pig). This pattern was not observed for older controls. In a computerized Stroop task (Experiment 3), J.H.M.'s naming latencies were abnormally prolonged in the conflict condition, relative to a baseline colour naming task. This effect was far in excess of that for controls. Finally, in a blocked cyclic naming task (Experiment 4), J.H.M.'s accuracy was poorer and her latencies slower when the pictures were semantically related than when they were unrelated, and this effect built up across successive presentation cycles. It was far in excess of that exhibited by older controls. We propose that J.H.M.'s pattern of impairment across these four very different tasks suggests an impairment to a lexical control mechanism, whose normal function is to modulate the flow of activation throughout the lexical network, so as to minimize the competitive effects of nontarget lexical items.

Cumulative and Non-Cumulative Semantic Interference in Object Naming: Evidence from Blocked and Continuous Manipulations of Semantic Context

“…J.H.M. (Scott & Wilshire, 2010) displayed a substantial and cumulative semantic context effect in the analysis of response times, hence presenting a similar pattern of results to those of the other patients (see Table 5 for details on the analysis of his accuracy). By contrast, the accuracy and, where applicable, the reaction times of most of the healthy controls (Biegler et al, 2008;Scott & Wilshire, 2010;Wilshire & McCarthy, 2002) or the control patients (K.V.…”

What we talk about when we talk about access deficits

“…The broader population of individuals with stroke aphasia also appears to exhibit progressively worse performance for related sets relative to unrelated sets and the effect is particularly pronounced in individuals with Broca's aphasia [28,38].…”

“…This has been shown in word-topicture matching [12,15,[18][19][20][21][22]24,32,33] and spoken-to-written word matching [16,18,25,26,32,33,35,36]. In addition, participants with non-fluent aphasia have been reported to exhibit exaggerated slowing when naming pairs of semantically related pictures than unrelated pictures [37,38]. Misleading phonemic cues (e.g.…”

“…IRQ [33]; AZ [32]; 9/10 pre-and 7/8 postsurgery glioma patients [24] c spoken-to-written word matching AZ [18,25,26,32,35]; MED [16]; IRQ [33]; FBI, NBC [36] naming pairs of pictures 2/2 semantic short-term memory deficit patients [37]; JHM [38] miscueing effects in picture naming 3/3 aphasic patients [39]; 5/6 SA patients [40] a ; seven SA patients [41,42] a,e matching non-verbal sounds to pictures or words AZ, BBB [30] selecting an object to complete a common task In addition to generally inconsistent performance, individuals with access deficits exhibit declining performance over repeated presentations of a stimulus, typically called a negative serial position effect (where 'serial position' refers to repetition of the same item, unlike in serial order recall tasks where it refers to position of different items). In the simplest studies, trials were presented in a ( pseudo-)random order and repeated multiple times.…”

Efectos de la edad de adquisición de las palabras en denominación de imágenes en sujetos afásicos hablantes del español

“…Si consideramos que los participantes fueron sujetos con daño cerebral y que la instrucción dada antes del experimento, con énfasis en respuestas rápidas que no permite una mayor reflexión acerca de la imagen presentada, podemos plantear que las respuestas fueron generadas a partir de un proceso rápido constituido por eventos de activación en cascada (Ellis & Young, 1988) que se inicia con el reconocimiento de la imagen y culmina con la codificación fonológica, la programación motora del habla y la correspondiente ejecución del habla de la o las palabras que conforman la respuesta. De acuerdo con este esquema, el acierto en una respuesta de denominación oral de una imagen observada es reflejo de la activación exitosa de un elemento léxico correcto y de una inhibición, también exitosa, de competidores que se encuentran en la red léxica (Scott & Wilshire, 2010); así, un mayor porcentaje de aciertos y, a la vez, un menor tiempo de respuesta ante un determinado grupo de palabras en comparación con otro grupo de palabras, puede considerarse un indicio importante de una activación más exitosa en un caso con respecto al otro. A partir de esto, se puede establecer que si los sujetos afásicos de este estudio presentaron una activación léxica más exitosa ante imágenes ATe que ante imágenes ATa, se espera que todas aquellas palabras que poseen un índice de edad de adquisición temprana tengan una mayor probabilidad de activación exitosa en sujetos afásicos; no obstante, no podemos descuidar que las variaciones en el grado de activación estarán evidentemente relacionadas también con otros factores tales como la edad del paciente, el grado de severidad del cuadro afásico y desempeño lingüístico premórbido, entre otros.…”