AUTHORS: Mohamed M. Eldesoky, Neveen A. Abd-Elraouf, Khaled E. Ayad, Enas E. Abu-Taleb.
METHODS: The study protocol, aim and importance were explained to all the participants. A written agreement form was signed by each participant. All the participants caught the iphone device containing the SBS in the upright position with the screen facing their mid of sternum and pressed it against their sternum while performed four tests (foot together, semi tandem, tandem and single leg stance) all done with eyes opened while the participant standing on the platform of the BBS (performing the test on BBS and the SBS at the same time as it is concurrent validity test) fig.1, 2, 3&4. The dominant leg was the leg in front in both tandem and semi tandem positions and the leg of weight bearing in the single leg stance position. Each test was done for 10 seconds and all participants performed experimental trials on level 8 Biodex Balance System difficulty with a familiarization trail prior to it. The overall stability index for each test was collected from experimental trial of each participant on both BBS and the same the overall postural sway was collected from SBS for each test and statistically analyzed.
RESULTS: Thirty healthy subjects participated in this study. Data obtained from the study group regarding overall posture sway of smart phone sway balance application were correlated with overall stability index of biodex balance system at stability level 8 under four conditions; foot together, semi tandem, tandem and single leg stance. The correlations between overall posture sway and overall stability index at level 8 were moderate negative significant correlation at foot together (r = -0.42, p = 0.02), moderate negative no significant correlation at foot semi tandem (r = -0.35, p = 0.053), strong negative significant correlation at foot tandem (r = -0.8, p = 0.0001), and moderate negative significant correlations at single leg stance (r = – 0.61, p = 0.0001).
CONCLUSION: Using of smart phone Sway Balance application in measuring the dynamic balance is valid as well as the static balance as it was compared with the laboratory gold standard Biodex Balance System which is proved to be valid in measuring dynamic balance. This is a very important result as it providing an easy using, portable, cost effective and objective method to evaluate the dynamic balance in any field. So, it is recommended to the physical therapists to use the SBS in testing and reevaluation of the dynamic balance and at any field.