Before revision:  11 years) with (n=18) and without ASD (n=18), we tested a set of  linear and nonlinear HRV measures, including phase rectified signal averaging (PRSA) , applied to a segment of ECG collected under resting conditions for their predictive properties of ASD . We identified HRV measures derived from time, frequency  and geometric signal-analytical domains which are changed in ASD children relative to peers without ASD and correlate to psychometric scores (p<0.05 for each) . Receiver operating curves area ranged between 0.71 - 0.74 for each HRV measure. Despite being a small cohort lacking external validation, these promising preliminary results warrant larger prospective validation studies.
After revision:  11 years) with (n=18) and without ASD (n=18), we tested a set of linear and nonlinear HRV measures, including phase rectified signal averaging (PRSA) , applied to a segment of ECG collected under resting conditions for their predictive properties of ASD . We identified HRV measures derived from time, frequency and geometric signal-analytical domains which are changed in ASD children relative to peers with receiver operating curve area of .89, and (2) differentiate such children from those with conduct problems or depression. Despite the small cohort and lack of prospective external validation, these promising preliminary results warrant larger prospective validation studies.