Semantic typicality effects in acquired dyslexia: Evidence for semantic impairment in deep dyslexia

Abstract

Background-Acquired deep dyslexia is characterized by impairment in grapheme-phoneme conversion and production of semantic errors in oral reading. Several theories have attempted to explain the production of semantic errors in deep dyslexia, some proposing that they arise from impairments in both grapheme-phoneme and lexical-semantic processing, and others proposing that such errors stem from a deficit in phonological production. Whereas both views have gained some acceptance, the limited evidence available does not clearly eliminate the possibility that semantic errors arise from a lexical-semantic input processing deficit.

Semantic Typicality Effects in Primary Progressive Aphasia

“…Notably, individuals with Wernicke's aphasia and acquired deep dyslexia showed impairments on other semantic tasks as well, [7][8][9] in line with their failure to show semantic typicality effects. Further, the patients with deep dyslexia 3 showed this pattern in both visual and auditory modalities.…”

“…Typical members of a category are processed faster than atypical members. 1,3,4 This typicality effect has been demonstrated in healthy participants in many studies using several experimental paradigms, including item ranking, lexical decision, category verification, and category naming. 1,2,5,6 In neurologically impaired participants, this effect has been demonstrated in nonfluent Broca's aphasia but not fluent Wernicke's aphasia 4 and in acquired phonological dyslexia but not acquired deep dyslexia.…”

“…The stimuli used in this study were the same as those used in a category verification task by Riley and Thompson, after Kiran and Thompson. 3,4 Fifteen typical and 15 atypical items were used for each of 3 superordinate natural object categories (birds, vegetables, fish), for a total of 90 items; an additional 90 items, unrelated to the aforementioned superordinate categories, were also used as nonmember exemplars, making a total 180 items used in the tasks. In addition, 12 training trials were administered for each condition-these training items included 4 typical, 4 atypical, and 4 nonmember items.…”

“…1,2,5,6 In neurologically impaired participants, this effect has been demonstrated in nonfluent Broca’s aphasia but not fluent Wernicke’s aphasia 4 and in acquired phonological dyslexia but not acquired deep dyslexia. 3 In both of these experiments with neurologically impaired participants, a category verification task was used, and patients with Broca’s aphasia and acquired phonological dyslexia demonstrated faster response times (RTs) for typical when compared to atypical exemplars of category items. However, for patients with fluent Wernicke’s aphasia and acquired deep dyslexia, no RT differences were found between the typical and atypical items.…”

La habilidad léxico-semántica en la Enfermedad de Alzheimer: Un estudio de la fluidez verbal con categorías semánticas

“…Con el avance de la enfermedad, el hablante pierde la capacidad de reconocer el significado de las palabras (Ardila, 2005), 'olvidando' primero las palabras de baja frecuencia y luego, las de alta frecuencia de uso (Arboleda Ramírez, 2016). La evolución hacia EA, además, va asociada a la modulación de una variable de naturaleza semántica, la tipicidad, que se manifiesta en que los hablantes dementes producen mayor número de unidades léxicas típicas (Vita, Marra, Spinelli, Caprara, Scaricamazza, Castelli, Canulli, Gainotti & Quaranta, 2014), es decir, aquellas que poseen un mayor número de rasgos característicos asociados a una categoría semántica (Riley & Thompson, 2010).…”