Table 1

Summary of previous COACH systems.

COACH Version
Tracking System
Decision-making system
Prompting system
Number of Subjects*
Related Publications

Version 1
Pattern wristband worn by the user
Neural networks interacting with a hard-coded taxonomy
Audio prompts, with one prompt for each step
10
[22,33]
Version 2
Using background subtraction to isolate the user's hands. Tracking of hands and task objects (i.e. soap and towel) using a preset colour model.
Fully observable Markov decision process (MDP). This technique assumes the world is fully observable; it does not take into account hidden variables, such as user responsiveness.
Audio prompts with three levels of assistance (minimal, moderate, and maximal) for each step.
4
[20,37-39]
Version 3 (system presented in this paper)
Colour based flocking.
[Belief monitoring system & policy] Partially observable Markov decision process (POMDP). This model takes into account hidden variables and is able to make decisions in conditions of uncertainty.
Audio and audio-video prompts with three levels of assistance (minimal, maximal, and maximal + video demonstration) for each step. Encouragement and a reminder regarding the activity the user is attempting added. Professional actor recorded prompts.
6
[18,19,21,23,25]

* Results from previous trials are not presented as they are not comparable because of the variance in the technologies and procedures that were used.

Mihailidis et al. BMC Geriatrics 2008 8:28   doi:10.1186/1471-2318-8-28