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Glimpses of the Stages of conceptual development of Pure Agraphia: 1884 – 2026
Poster Session A, Wednesday, September 30, 11:00 am - 1:00 pm, Wangari Maathai
Venugopal Balasuramanian1; 1Seton Hall University
Objective. The current study traces the conceptual development of ‘pure agraphia’ since Pitres’ inaugural work (1884) till the recent years that witnessed the use of AI technology in explaining and treating this clinical condition. This study attempts to answer the following research questions: What are the general classifications of Pure agraphia that emerged since 1884? Are there lesion patterns associated with the general classification? Are there sub-types of Pure motor agraphia and Pure linguistic agraphia? If so, what are the associated sites of lesions? What were the causal, theoretical accounts advanced to explain the varieties of dysgraphia? How did the theoretical advances set the stages for innovations in the interpretation of pure agraphia? Does the script system play a crucial role in advancing our knowledge of agraphia?Method. Procedure. As a review of cardinal publications on pure agraphia in the medium of English language, it identified relevant studies using search terms such as ‘agraphia’ ‘pure agraphia’, ‘motor agraphia’, ‘central (linguistic) agraphia’, and ‘peripheral agraphia’. Only case reports that explicitly described pure agraphia or its variants with neural lesion data and theoretical explanations were included. A total of thirty-two case reports were identified for the current study. Data required to answer the research questions were extracted from the review process. Results. Pure motor agraphia accounted for sixteen cases. Equal number of linguistic agraphia cases were identified. The stages of evolution of pure agraphia were identified by the causal reasoning (theory) used by the investigators. Initial stage witnessed the use of explanations such as 1) loss of memory for the complex coordinated movements for writing, (Lesion: foot of the second frontal convolution in the LH) 2) dyspraxic errors in the recall of letter outlines and execution of serial writing (Lesion: Left parietal lobe in aleft handed person), 3) Inability to translate verbal signals into motor movements for writing (Lesion Posterior part of the left prefrontal region. Coming to pure Linguistic agraphia, one can identify early explanations such as 1) Programs that translate letter choice into visual terms for writing is impaired (Lesion: posterior part of left prefrontal), 2) Impaired sensory-motor linguistic integration (Lesion: Left superior parietal), 3) Well formed (Kana) letters were accompanied by abnormal spelling with anagram or typing (Lesion: Left parietal infarct), 3) Isolated phonological agraphia with apraxia of speech (Lesion: inferior frontal and pre-central gyrus. The Dual-Route (D-R) model reinforced the view that access to orthographic representations can be achieved without the mediation of phonology, an idea that resonated well with some earlier studies. In contrast, a few researchers continue to argue in favor of the phonological mediation for the access of orthographic representation in writing. Hence, isolated agraphia with relatively spared oral reading will have implications for this issue. More recently, researchers on a pure linguistic dysgraphia case with a left Exner center lesion explained the characteristics using D-R and neural-network models. Multiple lesion sites associated with Isolated linguistic agraphia seem to favor a network model. Lastly, AI-based research was able to predict diagnostic features and potential treatments, .
Topic Areas: Disorders: Acquired, Writing and Spelling