PubMed · 8337556
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
A M Galaburda. 1993. Developmental dyslexia.. https://pubmed.ncbi.nlm.nih.gov/8337556/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
We present a case of "pure" or "apraxic" agraphia, a recognized writing disturbance, caused by intermittent focal seizures from the left posterior parasagittal parieto-occipital region. Pure agraphia has been described in focal lesions or as part of a generalized confusional syndrome. The posterior cerebral vascular territory is the characteristic site for the transient neurologic syndromes associated with cyclosporine toxicity. Our patient was at risk for this complication while recovering from a lung transplant, with elevated cyclosporine levels.
A longitudinal design was applied to differentiate between normal variations of psychomotor development and lasting handwriting deficiency (dysgraphia). Sixteen primary school children were tested with writing tasks that were recorded on a computer-monitored'XY tablet. These tasks represented different modules of the handwriting model of Van Galen (1991). Dependent variables were spatial errors, movement time, movement dysfluencies, trajectory length, stroke curvature, and the degree of neuromotor noise in the movement velocity profiles. The latter variable was measured by means of Power Spectral Density Analysis of the movement velocity signal, which revealed that movements of poor writers were substantially more noisy than those of proficient writers, with a noise peak in the region of neuromotor tremor. At the same time, the poor writers were less accurate. It was concluded that control of spatial accuracy rather than allograph retrieval or size control is the discriminating feature in dysgraphic children. Moreover, poor writers do not catch up with their peers within the 1 year time span tested.
We report the unusual case of AZO, who professionally used handwritten shorthand writing, and became dysgraphic after a stroke. AZO suffered from a complex cognitive impairment, and part of her spelling errors resulted from damage to auditory input processing, to phonology-orthography conversion procedures and to the ortographic output lexicon. However, analysis of her writing performance showed that the same variables affected response accuracy in alphabetic and shorthand writing; and, that the same error types, including transpositions, were observed in all tasks in the two types of writing. These observations are consistent with damage to the graphemic buffer. They suggest that, in multiple-code writing systems (e.g., stenography, Japanese, or in the case of multilingual speakers of languages that use different spelling codes), the graphemic buffer is shared by all codes.