Much has been discussed since the release of the Kinect about its accessibility for wheelchair users or those with a disability.
Early on Ablegamers.com published two articles - links below, that present the current issues and presented the hardware as it was back then. They present the issues clearly and honestly, highlighting some potential developments that were hoped would influence game development, with the disabled user in mind.
Kinect and the disabled part 1
Kinect and the disabled part 2
So where are we now? The Kinect is now established as a motion controller, both for the Xbox itself and with a PC. Whilst the Xbox Kinect games continue to cater for the commercial gaming population, the PC setup is slowly turning to address the more bespoke needs of those engaged in therapy or rehabilitation. The main influential factor over the success of any of these newly emerging Therapy games/software is that Microsoft endorse it and have done so by releasing its 'Service Development Kit (SDK)' for anyone to use and develop software with - something Nintendo never did.
This means that anyone with an idea and money to develop can put together a piece of software that will potentially cater for, and address, the needs of a patient and therapist. Software, such as SeeMe Rehabilitation, already demonstrates the potential that the Kinect/PC combination can offer.
There are still limitations though. The Kinect recognises skeletal points in order to work effectively but can still become very confused. Patients who present with hemiplegia, limited active movement in one arm or other similar postural deformities may find that the Kinect does not 'see' them. Equally whilst someone using a self propelled wheelchair will be recognised straight away, someone else using a powered wheelchair, with joystick control for example, may find themselves struggling to be noticed and registered within the game.