Background: Multiple sclerosis (MS) is a chronic inflammatory demyelinating neurodegenerative disorder with multiple lesions in the central nervous system. Motor abnormalities are considered to be a major cause of permanent occupational, social and daily disability of MS patients. However, due to serious limitations of existing methods for assessment of upper limb functioning, evaluation of coordinator and motor abnormalities in the upper extremities in clinical practice is difficult. Aim: To evaluate the efficacy of a computer kinetic method in the diagnosis of fine motor abnormalities of upper limbs in MS patients at early stage of the disease, when motor abnormalities in the upper limbs are not yet obvious. Materials and methods: The main study group included 42 patients with confirmed MS, who consented for testing and met the inclusion criteria (among them, absence of obvious motor and coordinator abnormalities in the arms). The mean age of the patients was 36 [29; 44] years. The control group included 31 healthy subjects with a mean age of 28 [21; 37] years. All the patients were assessed with an original computer kinetic system, including a two-minute test, when the patient had to follow a moving object on the screen with a computer mouse. Every test series resulted in 13 final characteristics. Results: The test of the dominant hand showed that compared to the control group, the MS patients without clinical motor abnormalities in the upper extremities spend 20% more time to move to the aim object (p 0.001), have a 18% lower output motor performance (p 0.001), make by 54% more recurrent returns to the aim object (p = 0.012), by 7% more crosses of the ideal trajectory of moving to the aim (p = 0.036), by 32% more deviations from the ideal trajectory of moving along the x axis and by 52% more along the y axis (p 0.001 for both comparisons), as well as they have a 12% lower mean rate of the movements during the computer test (p 0.001) and by 12% more rate picks (p = 0.003). Conclusion: Patients with confirmed MS, low degree of disability and absence of any clinically confirmed motor abnormalities in the upper limbs do have subclinical signs of motor abnormalities in the arms that can be identified by computer kinetic system.

There are a lot of methods for rendering of shell-space geometry, represented through voxel texture, known for today. While the topic is well studied in terms of techniques for applying this geometry onto surfaces, a little attention was paid to representation of sub-pixel details of the geometry. Such details are prone to produce aliasing artifacts and reduce performance due to bad cache utilization. In this paper we solve these problems by introducing levels of detail for voxel textures within shell mapping technique. The main problem here is that less detailed levels begin to contain semi-transparent voxels on the edge of an encoded surface, which requires additional handling. For this we present a new approach for order independent transparency rendering based on depth peeling. We extend the algorithm by adding additional resolving pass which allows to fully utilize hardware z-buffering to reduce amount of overdraw. This significantly reduces cost of each subsequent peeling pass. Empirically, 3-4 of such passes is enough to produce good quality results in most cases. Another issue with shell mapping techniques is that shell geometry is constructed offline, making base surface to be static. By slightly modifying the method, we made the construction to be performed on-the-fly on GPU and be applicable for animated surfaces.