Table 1.

Study characteristics on music therapy during kangaroo care focusing on the preterm infants’ responses and parent-infant interaction.

References	Country	Design	N of Participant Included	Number of Groups	Intervention Group Description	Preterm Infant’s Behavioral State (p-Value)	Preterm Infant’s Physiologic State (p-Value)	Parent-Infant Interaction (p-Value)	Other Outcomes (p-Value)
Arnon, 2014 [31]	Israel	crossover RCT	86 mother–infant dyads	MT during KC KC	2 sessions of live maternal singing for 40 min over 2 days; [10 min of KC alone, followed by KC and MT for 20 min; and 10 min of KC alone]	behavioral states * (p = 0.7)	HR (p = 0.67), RR (p = 0.38), O2 Sat (p = 0.23) HRV (LF/HF ratio, p = 0.04)		maternal anxiety ** (p = 0.03), mother’s HR (p = 0.21), mother’s RR (p = 0.31), mother’s O2 Sat (p = 0.18)
Epstein, 2021 [32]	Israel	crossover RCT	35 infants	MT during KC KC	3 sessions of live maternal singing for 40 min over 3 days; [10 min of KC alone, followed by KC and MT for 20 min; and 10 min of KC alone]	behavioral states *** (p = 0.03)	HR (p = 0.04), RR (p = 0.04), O2 Sat (p = 0.04) HRV (LF/HF ratio, p = 0.01)		maternal anxiety ** (p = 0.04); mother’s HRV (p = 0.07); mother’s O2 Sat (p = 0.15);
Ettenberger, 2014 [33]	Colombia	parallel RCT	30 infants; 26 parents	MT with parents during KC; MT with the babies alone Standard care	4 sessions of MT interventions for 8–25 min over 14 days Group 1: singing songs with the parents (lullabies/children’s songs/other songs); Group 2: Interventions with the use of the accompanying instruments (guitar, ocean drum, gato-box, ocean drum alone, mixed instruments).		HR (n/a) O2 Sat (n/a), weight gain (p = 0.05)	Bonding **** (p = 0.49)	maternal anxiety ** (p = 0.01 for Factor 2 before the first intervention; p = 0.0418 for Factor 6 after the last intervention), Length of Hospitalization (p = 0.39)

Annotation: HR, heart rate; HRV, heart rate variability; LF/HF, low frequency/high frequency; n/a, not available; O2 Sat, oxygen saturation; p, significant; RCT, randomized controlled trial; RR, respiratory rate. Notes: * based on a seven-point score based on the criteria of Als to assess the infants’ behavioral states as: deep sleep, light sleep, drowsy, quiet awake or alert, actively awake and aroused, highly aroused, upset or crying and prolonged respiratory pause of more than eight-seconds; ** STAI, State-trait anxiety inventory; *** NIDCAP manual for naturalistic observation and the Brazelton Neonatal Behavioral Assessment; **** MIBS, other-to-Infant Bonding Scale.