In order to better understand the neuropsychological mechanisms and anatomic loci that underlie acquired disorders of writing (and spelling), consecutive patients with acquired agraphias will be studied. The goal is to prospectively test a neuropsychological model of writing that was developed from preliminary studies and previous literature. These studies analyzed the behavior and pathological anatomy (by computerized tomography, CT) of the following agraphias: phonological, lexical, semantic and apractic. The proposed underlying anatomy included: supramarginal gyrus or underlying insula (phonological), posterior angular gyrus (lexical), areas thought to be important for language comprehension (semantic) and the parietal lobe (apractic). From these agraphias the specific functional components of the model were developed. They include linguistic (phonological, lexical, semantic) and motor components (graphemic area for apractic agraphia). In addition, the model proposes that there is a transitional phase when linguistic information is passed to the motor systems. Using a previously designed and normed writing, spelling and reading battery, as well as other language and non-language tests, the investigators will study a consecutive series of patients with left hemispheric lesions. All patients will be given the entire battery and all will have CT. The data generated from these tests will then be analyzed using a variety of statistical methods in order to validate or invalidate the behavioral and anatomic hypotheses predicted by the model. The results of this study will help lead to a better classification of the agraphias and a better understanding of the brain-behavior relationships underlying these common language disorders. Further development of a specific model of writing may lead to the development of additional therapeutic approaches to agraphia.
| Roeltgen, D P; Tucker, D M (1988) Developmental phonological and lexical agraphia in adults. Brain Lang 35:287-300 |
