Dementia involves the loss of cognitive abilities and represents a decline from the prior level of function which impairs functional abilities in day-to-day life. No previous experimental research has been done to assess mental imagery (MI) effectiveness in the motor, cognitive and emotional status of individuals with early-stage dementia. One hundred and forty older individuals with early-stage dementia from the Day Care Centre of the Alzheimer Association in Athens will take part in this study. The sample will be randomly divided into three groups: MI and physical exercise (intervention group), only physical exercise (1 st control group), and neither MI nor physical exercise (2 nd control group). Assessment will be obtained one week prior to the program, in the middle of the program (6 th week of the intervention program) and after the end of the program (13 th week of the intervention program). Participants of the intervention group will perform a 30-minute MI programme after the end of every physiotherapy session. Reliable and valid instruments will be used to assess the primary outcomes, i.e., balance and functional status as well as the secondary outcomes i.e., cognitive ability, emotional state and quality of life. The two-way Mixed ANOVA with factors ‘intervention’ (between groups) and ‘time’ (within group) will be used as a statistical analysis. Approvals of clinical trial protocol: a) UNIWA Research Committee study protocol approval: 93292 - 26/10/2021. b) ClinicalTrials.gov: ID NCT05232526.