Noémie Auclair-Ouellet

The Role of Basal Ganglia in Language Production: Evidence from Parkinson's Disease

According to the dominant view in the literature, basal ganglia do not play a direct role in language but are involved in cognitive control required by linguistic and non-linguistic processing. In Parkinsons disease, basal ganglia impairment leads to motor symptoms and language deficits; those affecting the production of verbs have been frequently explored. According to a controversial theory, basal ganglia play a specific role in the conjugation of regular verbs as compared to irregular verbs. We report the results of 15 patients with Parkinsons disease in experimental conjugation tasks. They performed below healthy controls but their performance did not differ for regular and irregular verbs. These results confirm that basal ganglia are involved in language processing but do not play a specific role in verb production.

Improving verb anomia in the semantic variant of primary progressive aphasia: the effectiveness of a semantic-phonological cueing treatment

The semantic variant of primary progressive aphasia (svPPA) is known to affect the comprehension and production of all content words, including verbs. However, studies of the treatment of anomia in this disorder focused on relearning object names only. This study reports treatment of verb anomia in an individual with svPPA. The semantic-phonological cueing therapy resulted in significant improvement in naming abilities, for treated verbs only. This case study demonstrates that improvement in verb-naming abilities may be possible in svPPA. The almost complete maintenance of the treatment’s effects in the patient 4 weeks after the end of the therapy also suggests improvements may be durable, at least in the short term, for some individuals with svPPA.

Regularity and beyond: Impaired production and comprehension of inflectional morphology in semantic dementia

Studies on inflectional morphology in semantic dementia (SD) have focused on the contrast between the regular and the irregular English past-tense. These studies aimed to contrast the claims of single- and dual-mechanism theories. However, both theories can account for impaired production of irregular verbs observed in SD. According to the dual-mechanism theory, this impairment is related to word-retrieval difficulties, while according to single-mechanism theory it is the consequence of semantic impairment. However, authors suggest that it is time to envision a broader role for semantic memory in the production of semantically encoded aspects of inflectional morphology. This study reports the performance of 10 French-speaking patients with SD in three tasks of inflectional morphology. Their performances were compared to those of a group of 20 age-, gender- and education-matched adults without cognitive impairment. Results show that SD patients had difficulties producing tense and person inflection in verbs and pseudo-verbs, whether regular or pseudo-regular. In a second task in which participants were directly exposed to regularity manipulations, SD patients tended to choose a more typical or predictable alternative over a correctly inflected verb. Results of the third task show that their difficulties in producing semantically encoded aspects of inflection, such as tense, are related to difficulties to understand the semantic content conveyed by inflectional morphemes. Overall, these results support the claim that semantic impairment can cause morphological deficits that do not only affect irregular verbs, but that also have impacts on the production and comprehension of semantic information conveyed by inflectional morphemes.

Production of morphologically derived words in the semantic variant of primary progressive aphasia: preserved decomposition and composition but impaired validation

Abstract Although there is growing interest in inflectional morphology in semantic variant primary progressive aphasia (svPPA), derivational morphology has rarely been studied in this population. This study reports the performance of N.G., a 72-year-old-woman with svPPA in a verb production task designed to entail morphological processing (composition, decomposition) and self-appraisal of her productions. N.G. demonstrated an over-reliance on morphological processing and failures in her appraisal of root/affix combinations that resulted in the production of morphological paraphasias and neologisms. Her performance in lexical decision of verbs and pseudo-verbs points to the involvement of semantic impairment in these difficulties.

Toward an executive origin for acquired phonological dyslexia: a case of specific deficit of context-sensitive grapheme-to- phoneme conversion rules.

Phonological dyslexia is a written language disorder characterized by poor reading of nonwords when compared with relatively preserved ability in reading real words. In this study, we report the case of FG, a 74-year-old man with phonological dyslexia. The nature and origin of his reading impairment were assessed using tasks involving activation and explicit manipulation of phonological representations as well as reading of words and nonwords in which the nature and complexity of grapheme-to-phoneme conversion rules (GPC rules) were manipulated. FG also underwent an extensive neuropsychological assessment battery in which he showed impaired performance in tests exploring verbal working memory and executive functions. FG showed no phonological impairment, and his performance was also largely unimpaired for reading words, with no effect of concreteness, grammatical class, morphological complexity, length or nature and complexity of the GPC rules. However, he showed substantial difficulties when asked to read nonwords with contextual GPC rules. The contribution of FG’s executive deficits to his performance in reading is discussed.

Conception or *conceivation? The processing of derivational morphology in semantic dementia

ABSTRACT Background: Only a few studies have focused on derivational morphology in semantic dementia (SD). The productive and componential nature of derivational morphology as well as recent findings in psycholinguistics suggest that semantic cognition would be involved in the production and comprehension of derivational morphemes and derived words. Therefore, participants with SD might present impairment in derivational morphology. Aims: This study aims to specify semantic cognition’s involvement in the production and comprehension of derivational morphemes and morphologically complex words in SD participants. This involvement was considered in relation to the production of morphologically complex words, the comprehension of the meaning conveyed by morphemes, and the capacity to distinguish between words with a real vs. an apparent morphological structure. Methods and Procedures: Ten French-speaking SD participants completed three tasks of derivational morphology. Their performances were compared to those of a group of 20 age-, gender- and education-matched adults without cognitive impairment. Outcomes and Results: Compared with participants of the control group, SD participants had more difficulty producing nouns derived from verbs that follow less-frequent patterns of root allomorphy, while their performance was less affected when they could rely on basic morphological decomposition/composition abilities. Participants with SD also had more difficulties to match derived words and pseudo-words to a definition and to distinguish between pairs of real morphological antonyms and pseudo-morphological non-antonyms. Conclusions: These results support the involvement of semantic cognition in the validation of morpheme combinations and in derivational morpheme representation. Difficulties in the production and comprehension of derived words and derivational morphemes are another of the many consequences of central semantic impairment that characterises SD. More studies are needed to develop tests and further characterise the involvement of semantic cognition in derivational morphology.