The aim of the research project is to get knowledge about the use of cognitive assistive devices in the daily life of persons with cognitive impairment caused by dementia. The objectives are to enhance the use of assistive technology in the area of dementia in order to secure a high degree of personal independence and quality of life. 29 persons with the diagnosis of dementia and/or their relatives as well as professionals from the service delivery of assistive technology were interviewed about their experiences on the assessment of need for assistive devices, the implementation and the use of the cognitive assistive devices in the daily life. A thematic qualitative analysis focuses on the usefulness and benefit of cognitive assistive technology in the daily living for persons with dementia and on the function of the service delivery system in order to find relevant procedures for delivering of cognitive assistive technology to persons with dementia. The results show that assistive technology can enhance the independence and quality of life for people with dementia, and therefore promote a sort of new interfaces between formal and informal elderly care in the area of dementia. A guideline for service delivery of assistive technology has been developed concerning the area of dementia, and the case stories with description of assistive devices and their use show the effect on formal and informal care.