This study used healthy elderly participants with the age of 65-85 years. Eighty-four elderly participants were recruited by announcing the study information at the elderly homes. Sample size calculation was performed using G\*Power software (G\*Power version 3.1.9.2, University Kiel, Germany). To our knowledge, no study compare the effects of physical exercise, virtual reality and brain exercise on balance of the elders. Based on previous finding on the effects of virtual reality on balance of the elderly, a total of 84 participants were required at confidence level (α) of .05 and power (1-β) of 0.80. Participants who were interested in participation underwent a screening process using inclusion-exclusion criteria and receive brief information regarding the study. If they met all inclusion criteria, the consent process was performed. To ensure they understood the study, they were simply asked regarding the study (i.e. objectives, benefits, etc.) before signing the consent form.

After the participants provided a written informed consent, all participants filled out the information sheet and demographic data were collected. After that, age matching with range of ± 5 years and random allocation to different studies groups were done. Pretest assessment for balance by BBS and TUG, cognitive function by TUGC and MOCA, muscle strength by 5 TSTST and Hand Grip Strength (HG) and fear of falling by FES-I and perspective of exercise by questionnaires were done and recorded by blinded assessor. In this study, random allocation of the participants to different study groups; physical exercise group (PE), virtual reality group (VR), brain exercise group (BE) and control group; was done by the medical doctor and intervention was given the physical therapist from the study area which is the elderly home. All the assessments were done by the principal researcher. The assessor was blinded to reduce the bias which might come from the assessor's expectation.

After that, all the participants from intervention groups were explained and demonstrated about the respective interventions until they clearly understand about the intervention program before commencing the intervention program. The PE, VR and BE groups got their respective intervention for 30 minutes per sessions, 3 non-consecutive days per week for 8 weeks. The control group was reminded not to participate in any other exercise or intervention program except their routine daily activities for 8 weeks. Participants from PE group needed to do the 5-minute warm-up, 20-minute core content (upper and lower limb strengthening exercises and balance challenging exercises), and 5-minute cool down exercise programs. For the virtual reality group, the participants were reminded to play the game according to the program and try to get as high a score as possible they can. This intervention program included 10 games. The participants were asked to choose 6 games from the list before each 30-minute session, and were asked to choose the games to include the upper limbs, lower limbs, and also for both strength and balance challenges instead of choosing the games that need to use only upper limbs or lower limbs, and were just for strength and balance gain. For the brain exercise, participants needed to play cognitive stimulating games; Chinese Checker, Jenga and Memory Matched pair game; in the sitting position. The participants needed to paly 10 minutes for each game and total duration for all 3 games was about 30 minutes. After 8-week study period, post-test assessments were done to find out the effect of interventions.

The statistical analyses were performed by using SPSS for windows version 18.0, statistical software package. The value of p\<0.05 was considered to indicate statistical significance. As the objective of this study was to find out the effects of PE, VR and BE on balance, cognitive function, muscle strength and fear of falling in the elderly. Two-way mixed ANOVA was used to test the variance differences among the four groups with post-hoc analysis as appropriately. Prior to utilization of statistical tests, descriptive statistics were performed and statistical assumptions were tested. Transformation will be performed if the data were not normally distributed. Appropriate statistical tests (parametric vs. non-parametric) were performed to determine the effects of different interventions in this study on balance, cognitive function, muscle strength and fear of falling in the elderly. Post-hoc power analysis was also performed.