Aphasia is a cognitive disorder that impairs speech and language. From interviews with aphasic individuals, their caregivers, and speech-language pathologists, the need was identified for a daily planner that allows aphasic users to independently manage their appointments. We used a participatory design approach to develop ESI Planner (the Enhanced with Sound and Images Planner) for use on a PDA and subsequently evaluated it in a lab study. This methodology was used in order to achieve both usable and adoptable technology. In addition to describing our experience in designing ESI Planner, two main contributions are provided: general guidelines for working with special populations in the development of technology, and design guidelines for accessible handheld technology. Categories & Subject Descriptors: K.4.2 [Computers and Society]: Social Issues ? Assistive technologies for persons with disabilities; H.5.2 [Information Interfaces and Presentation]: User Interfaces - Evaluation/ ...