Background: Preventing the progression of dementia is a widespread challenge. However, currently there is limited evidence supporting the effectiveness of dementia rehabilitation. Methods: We practiced activity reminiscence therapy (ART) as brainactivating rehabilitation for both lucid and demented persons (n = 18) in a day-service setting as well as in a group home. The ART sessions were conducted 1 hour every week for 12 weeks (intervention period). We compared the results of three cognitive tests (the Mini-Mental State Examination, the Kana Pick-out test and the 'logical memory' component of the Wechsler Memory Scale-Revised) and four behavior and caregiver s burden scales (the Clinical Dementia Rating, the Multidimensional Observation Scale for Elderly Subjects, the Dementia Behavior Disturbance scale and the Zarit Caregiver Burden Interview) conducted during the control period with those taken during the intervention period. At the end of the intervention period, we interviewed the staff and families individually to assess whether the participants seemed to have changed after intervention and, if so, how. Results: In cognitive tests, only immediate and delayed recall of the Wechsler Memory Scale-Revised showed significant improvement. None of the four behavior and caregiver s burden scales showed any significant changes after intervention. However, the interviews showed improvements in subjective aspects of communication, interaction and behavior. Conclusion: ART uses old-style tools. The nostalgia brought about by using these familiar tools led to effective recall of experiences, in which the participants taught the staff how to use the tools, which were unfamiliar to the staff. Through this role-reversal, they gained a sense of self-worth and a desire to live. Due to the reconstructed relationship between participants and caregivers, we consider ART to be effective in maintaining and improving emotional functions, activities of daily living and memory. ART should be useful for both lucid and mildly demented persons as brain-activating rehabilitation therapy.