highly significantp < 0.0001
The test for residual heterogeneity was highly significant ( p < 0.0001). 4.4.1.2 DBS primary for treating chronic pain (DBS-P) analysis The test of moderators for age as a predictor was not significant F(df1 = 1, df2 = 22) = 1.1608, ( p = 0.29), indicating that age did not significantly moderate the effectiveness of DBS-P for chronic pain The estimated amount of residual heterogeneity (tau^2) was 43.86, indicating considerable heterogeneity among the studies.