A clinical evaluation of a remote mobility monitoring system based on SMS messaging

The objective of this work was to evaluate the accuracy and viability of a mobility telemonitoring system, based on the short message service (SMS), to monitor the functional mobility of elderly subjects in an unsupervised environment. A clinical trial was conducted consisting of 6 elderly subjects; 3 male, 3 female (mean: 81.7, SD: 5.09). Mobility was monitored using an accelerometer based portable unit worn by each monitored subject for eleven hours. Every 15 minutes the mobility of the subject was summarized and transmitted as an SMS message from the portable unit to a remote server for long term analysis. The activPAL Trio Professional physical activity logger was simultaneously used for comparison with the portable unit. On conclusion of the trial each subject completed a questionnaire detailing their satisfaction with the portable unit and any recommendations for improvements. Overall a percentage difference of 2.31% was found between the activPAL Trio and the portable unit for the detection of sitting. For the combined postures of standing and walking the percentage difference was calculated as 2.9%. A bivariate correlation and regression analysis was performed on the entire data set of one subject. Strong positive correlation's were found for the detection of sitting (r = 0.996) and for the combined postures of standing and walking (r = 0.994). Subjects suggested that a lighter, smaller and wireless unit would be more effective.