Soft tissue rapid prototyping in neurosurgery.

As part of our research into the fluid hydrodynamics of the human ventricular system, a fused deposition model of the human ventricular system was made using magnetic resonance imaging (MRI) data. This article describes the manufacturing of a positive cast of the ventricles as a first step in the construction of a hollow model. After decryption of the original MRI file (ACR-Nema format), the MRI slices were reassembled semiautomatically and a rapid prototyping station produced a resin model. Because of its ease and speed, this method harbors great potential for teaching purposes, research, and preoperative planning in complex three-dimensional soft tissue targets.

Visual and phonological factors in acquired dysgraphia.

The written spelling behaviour of a severely aphasic patient, whose many errors suggested a strong influence of visuo-spatial representations, is described. An experiment was carried out to confirm or refute the importance of visual factors in spelling to dictation. The strongest confirmatory evidence was the patient's propensity for writing the individual letters of a word in nonlinear order, i.e. not left to right, sometimes even beginning in the middle of a word. The influence of whole visual word-contours was also examined. Analysis of the results suggested that, in addition to the visual element, certain phonological factors played a small part in the patient's repertoire of strategies and this was confirmed in a second experiment. The patient's multi-strategy approach to written spelling is discussed on the basis of an information-flow model. This leads on to consideration of the possibility of consolidating the residual phonological system as part of a re-education plan.

Analysis and remediation of aphasia in the U.S.S.R: the contribution of A. R. Luria.

This paper surveys the contribution of A. R. Luria to aphasiology, emphasising the unique extent to which he integrated theory and therapeutic practice. The influence exerted by two prominent Russian figures, Pavlov and Vygotskii, is discussed. Luria's view of the primary defects underlying the main forms of aphasia is summarised; this is followed by a brief account of his application of certain notions of structural linguistics, including Jakobson's interpretations of the breakdown of language following brain damage. Examples are given of the wide range of simple tests included in Luria's neuropsychological investigations. The factual part of the article culminates in some examples of his methods of restoring higher cortical functions, in particular, verbal skills. The summary criticises certain aspects of Luria's analysis as being too mechanistic and simplistic, and cites criticisms of details from other workers, but considers many of his insights and the total coherence of his view of cortical functioning and cortical disturbance to be still of the utmost importance for clinicians undertaking aphasia therapy. The need for therapists everywhere to develop language rehabilitation with as systematic a basis as Luria's is stressed.

Occupational resettlement in aphasia.

An account is given of the occupational resettlement and progress of four patients with severe dysphasia, due to cerebrovascular accidents. The dysphasia was predominantly expressive in two cases and predominantly receptive in the other two. Three of the patients were resettled in gainful employment and the fourth in a sheltered occupation. In all four cases, the patients attained a very adequate level of working efficiency, distinctly above what had been anticipated on clinical and psychometric grounds. While these results are encouraging, it is stressed that fuller and more extensive long-term follow-up studies of occupational resettlement in aphasia are necessary before firm conclusions can be drawn.