Vision system assists dementia sufferers with personal tasks

Older adults living with cognitive disabilities such as Alzheimer's disease have difficulty completing activities of daily living. They forget the proper sequence of tasks that need to be completed, or they lose track of the steps that they have already completed. The current solution is to have a human caregiver assist the patients. The dependence on a caregiver is difficult for the patient and can lead to anger and helplessness, particularly for private tasks such as using the washroom.

Older adults living with cognitive disabilities such as Alzheimer's disease or other forms of dementia have difficulty completing activities of daily living (ADLs). They forget the proper sequence of tasks that need to be completed, or they lose track of the steps that they have already completed. The current solution is to have a human caregiver assist the patients at all times. The dependence on a caregiver is difficult for the patient and can lead to anger and helplessness, particularly for private ADLs such as using the washroom.

A real-time system has been devised by Jesse Hoey and colleagues at the University of Dundee (Dundee, UK; www.computing.dundee.ac.uk) to assist persons with dementia during handwashing. Assistance is given in the form of verbal and/or visual prompts, or through the enlistment of a human caregiver's help. The system uses only video inputs and combines a Bayesian sequential estimation framework for tracking hands and towel, with a decision theoretic framework for computing policies of action--specifically a partially observable Markov decision process. A key element of the system is the ability to estimate and adapt to user states, such as awareness, responsiveness, and overall dementia level.

In operation, video is grabbed by an overhead Point Grey Research (Vancouver, BC, Canada; www.ptgrey.com) Dragonfly II IEEE-1394 camera and fed to a hand-and-towel tracker. The tracker reports the positions of the hands and towel to a belief monitor that tries to estimate where in the task the user is currently: what have they managed to do so far and what is their internal mental state. The belief about where the user's state is is then passed to the policy. The policy maps belief states into actions: audio-visual prompts or calls for human assistance.

More details can be found in a paper, presented at ICVS 2007: "Assisting Persons with Dementia during Handwashing Using a Partially Observable Markov Decision Process," by Jesse Hoey, Axel von Bertoldi, Pascal Poupart, and Alex Mihailidis, in Proceedings of the International Conference on Vision Systems, ICVS 2007, Biefeld, Germany (March 2007).


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