The aim of our communication is to present results of an evaluation of two cognitive stimulation software tools (“ProfessionalTool” and “StudyTool”) and to give recommendations to improve their usability. The evaluation was conducted using a test user on a group of 32 seniors (average age 78.19 years) and a group of 15 people (mean age 30.47 years). The “ProfessionalTool” software includes thirty exercises targeting different cognitive skills. The second software – “StudyTool”- has been designed by our team applying user-centered design. The performances of these interfaces were measured using a questionnaire of satisfaction and a heuristic inspection observation grid, based on ergonomic criteria. The scores obtained by each group and each method of data collection were calculated and compared. An important result is that the number of problems encountered by users in the cognitive stimulation tasks is M=10.09 with ProfessionalTool; i.e. a senior user remained stuck for ten minutes on a settings screen. The results of the questionnaire also indicate problems concerning visual ergonomics guidelines, workload, control and error handling, uniformity and consistency, significance and compatibility. This experience highlights the importance of ergonomics in cognitive stimulation software. Their adaptation to a specific public need is often insufficient, especially as the users have troubles with memory and attention. Our study enables us to make a positive contribution of ergonomic human- computer interaction to cognitive stimulation. Beyond the actual effect of cognitive stimulation that is no longer in doubt, the challenge is to support the use and empower the user. This is only possible through tailored interactions.