Systematic evaluation of current control devices used by people with intellectual disabilities in non-immersive virtual environments.

Virtual environments have a role to play in facilitating the acquisition of living skills in people with intellectual disabilities, improving their cognitive skills and providing them with entertainment. However, the currently recommended devices to allow navigation in and interaction with the environments are difficult to use. Using a methodology established in an earlier study, the study aims to systematically document the performance of users with the currently recommended devices in order to (i) inform the design of a usable control device or devices and (ii) act as a baseline against which they can be evaluated. 40 people with severe intellectual disabilities aged 21-67 years used four environments with an equal number of sessions with the different devices being evaluated. Results indicate that when forward movement is provided by the software using the mouse for both navigation and interaction allows better performance both initially and after exposure than using the fire button on the joystick. When the user had to initiate forward movement with the navigation device, the joystick allowed better performance than the arrows on the keyboard. Preventing slippage of the joystick base would make its use much easier and it is suggested that separate devices are retained for navigation and interaction.

Isolation of a group of glycolipid toxins from seedheads of annual ryegrass Lolium rigidum Gaud.) infected by Corynebacterium rathayi.

A group of highly toxic compounds was isolated from galled seedheads of annual ryegrass (Lolium rigidum Gaud.) containing Corynebacterium rathayi. Purified extracts were resolved by reverse-phase high-performance liquid chromatography into eight main fractions which have been partially characterised and shown to be toxic to nursling rats. A mixture of the toxins also produced clinical signs and brain lesions in lambs consistent with annual ryegrass toxicity. The name 'corynetoxin' is tentatively proposed for the series, individual members being designated according to their order of elution from the high performance liquid chromatography column as corynetoxins 1 to 8. The two main fractions are corynetoxins 3 and 4 of which the former has been crystallised. They appear to be of glycolipid character, 3-hydroxyheptadecanoic acid and a C6 amino sugar being identified among the hydrolysis products of corynetoxin 3, and heptadec-2-enoic acid and a C6 amino sugar from corynetoxin 4.