The neural correlates of therapy with semantic feature analysis in chronic anomia: An event-related fMRI study
Brain and Language 99 (2006) 8–219 www.elsevier.com/locate/b&l
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The neural correlates of therapy with semantic feature analysis in chronic anomia: An event-related fMRI study Karine Marcotte a
, Paolo Vitali a, Ana Paula Delgado c, Ana Ine´s Ansaldo
Centre de recherche´ de l’Institut universitaire de ge´riatrie de Montre´al, Unite´ de Neuroimagerie, Montre´al, Que´bec, Canada b Speech-Communication Sciences Department, University of Montreal, Que´bec, Canada c Hoˆpital du Sacre´-Coeur de Montre´al, Montreal, Que´bec, Canada d Faculty of Medicine, University of Montreal, Que´bec, Canada Accepted 6 July 2006
Word retrieval is one of the most striking and persistent deﬁcits following aphasia. Among the therapy approaches aimed at improving naming, Semantic feature analysis (SFA) aims to improve word access by boosting semantic representations in order to facilitate the phonological retrieval (Boyle & Coehlo, 1995). Thus, SFA intends to elicit the targeted response by activating semantic networks without inhibiting related or creative responses. However, the impact of SFA on the neural substrate of the recovery from anomia remains to be determined, and could provide interesting cues for a better understanding of the language-therapy-dependent neural changes underlying the recovery from aphasia. This event-related fMRI examined the impact of SFA on the neural substrate sustaining the recovery from chronic and severe anomia.
During fMRI scanning (3Tesla Siemens), CM accomplished a visual naming task. He was instructed to name the pictures corresponding to the nouns and verbs, and to say ‘‘BABA’’ for the baseline items. Pictures were presented, in two runs, for a total of 180 stimuli, jittered with a variable ISI.
Methods CM, is a 66 years old, right-handed male. He suﬀered a left fronto-temporal CVA in 2002, leading to severe non-ﬂuent Broca’s aphasia and a verbal apraxia. He received intensive language therapy for 3 years. In 2004, he returned to speech therapy and was followed for 3 months with a SFA approach, with the aim of improving word retrieval given that SFA resulted in the improvement of naming with nouns and verbs (Ansaldo & Delgado, 2004), it was decided to extend its application to a larger number of items. Further, an e-r fMRI study was accomplished before and after therapy to examine the corresponding neural changes.
Language therapy with SFA CM attended three-60 min. sessions per week, for a total of 3 weeks. Stimuli were presented individually in a random order and CM was asked to name each picture. When CM was unable to name a picture, he was prompted with WH-questions aiming at the access of the semantic features of the target, such as category, function, physical properties, etc. Any response given served to elaborate more prompts. After three prompts, the target word was orally provided so that CM who could repeat it. Post-therapy scanning CM completed the visual naming task during f-MRI scanning, as in pre-therapy scanning. Stimuli were pictures corresponding to 15 trained words, 15 untrained missed words, and 15 accurate words, for both nouns and verbs categories. Results
Procedure Behavioral data analysis Two baseline evaluations, with the Snodgraas and Vanderwart (1980) images showed a stable word naming performance. For both nouns and verbs, 60 pictures corresponding to 30 correctly named and 30 incorrectly named words, were selected from the pre-therapy baseline. Additionally, 30 pictures were transformed into non-object or action images, by numerical distortion, so as to serve as baseline condition, for the fMRI subtraction.
Therapy was a signiﬁcant (p < .01) improvement with both treated nouns and verbs after SFA therapy. Thus, CM named correctly 80% of the trained nouns and 26.7% of non trained nouns. With verbs, CM correctly named 73.3% of the trained items, in comparison to 26.7% of the untrained ones (p < .01). Analyses of error types before and after SFA therapy did not show any signiﬁcant diﬀerences.
Abstracts / Brain and Language 99 (2006) 8–219 fMRI data analysis FMRI data was analyzed with statistical parametric mapping (Wellcome Department of Imaging Neuroscience). Before the therapy, there was active participation of the right hemisphere in the successful naming of nouns and verbs. Thus, signiﬁcant activations (p < .05), with nouns included the right homologous to Broca’s area, whereas with verbs they included: the right inferior temporal gyrus, and the left superior parietal cortex, in a bilateral expanded network. After therapy, signiﬁcant activation with nouns and verbs (p < .05) concerned the same regions for nouns, whereas with verbs, signiﬁcant activation loci were more concentrated in the right cerebral hemisphere, and included the right inferior temporal gyrus and Broca’s homologous. Conclusions SFA is an eﬃcient approach to improve naming deﬁcits, and its value is speciﬁc to treated words, both in the noun and verb categories. Neuroimaging data obtained before and after therapy show that both hemispheres sustain naming in chronic and severe aphasia. Further, these results show that signiﬁcant behavioral improvement with treated nouns did not correspond to major changes with activation maps, whereas it
was expressed by a contraction of the network sustaining improvement on naming verbs. Combining fMRI with functional and eﬀective connectivity analyses could improve our understanding on the impact of language therapy on the neural substrate of the recovery from anomia. References A.I. Ansaldo, A.P. Delgado (2004). Eﬃcacy of Aphasia Therapy: A combined approach for the treatment of word retrieval deﬁcits in chronic Broca’s aphasia. International Aphasia Rehabilitation Conference, Milos Island, Grece, june 12-16.. Boyle, M., & Coehlo, C. A. (1995). Application of Semantic Feature Analysis as a Treatment for Aphasic Dysnomia. American Journal of Speech Language Pathology, 4(4), 94–98. Collins, A. M., & Loftus, E. F. (1975). A spreading activation theory of semantic processing. Psychological Review, 52, 407–428. Rosenbeck, J. C., LaPointe, L. L., & Wertz, R. T. (1989). Aphasia: A clinical approach. Boston: College-Hill. Snodgraas, J. G., & Vanderwart, M. (1980). A standerdized set of 260 pictures: Norms for name agreement, image agreement, familiarity, and complexity. Journal of Experimental Psychology: Human Learning and Memory, 6, 174–215.