Intervention
Participants randomized to music therapy (MT) plus standard care or standard care alone during NICU admission, or to MT plus standard care or standard care alone postdischarge, using computer-generated randomization (ratio 1:1, block sizes of 2 or 4 varying randomly), stratified by site (51 allocated to MT NICU, 53 to MT postdischarge, 52 to both, and 50 to neither). MT consisted of parent-led, infant-directed singing tailored to infant responses and supported by a music therapist 3 times per week throughout hospitalization or 7 sessions across 6 months’ postdischarge.