<qa>  What is the Pearson correlation coefficient calculated between the daily Activity and two Actigraph parameters?With regard to concurrent validity of the Medtronic Patient Activity measurement, the Pearson correlation coefficient will be calculated between the daily Patient Activity minutes per day and two Actigraph parameters: daily activity count and steps per day. Correlation coefficients will be calculated for the baseline, 3-month, and 9-month monitoring periods to provide a greater number of sampling days. Correlation coefficients will also be calculated for changes in daily activity measurements between baseline and 3 months and baseline and 9 months to determine concurrent validity of change in daily activity measurements. 