The project studied 40 infants, divided into three groups: those hospitalised and receiving music therapy; those hospitalised and not having music therapy; and healthy babies, cared for at home, without music therapy.
Infant neuropsychologist Dr Carol Newnham performed a behavioural development test twice on each infant, about a month apart.
During that month, the hospitalised infants who received music therapy had up to 12 sessions of the therapist gently singing to them and touching them in a way that directly related to the therapist's perception of the social needs of the babies.
"We found that music therapy supported the infants' behaviour - these infants maintained the same levels of irritability and crying that they had at admission," says Dr Malloch.
"Meanwhile, those babies in the Neonatal Unit who did not have music therapy deteriorated in their irritability and crying behaviour - coping less with their hospitalisation as time went on.
"It's likely the babies who received music therapy used up less energy when compared with the babies who did not receive the therapy. If a baby is less irritable and cries less, this has implications for rate of healing and weight gain, two significant factors which contribute to the length of a hospital stay."
These research findings were reported at the World Congress on Music Therapy held in Brisbane last year, and will be published in an international music therapy journal this year.
An Australian Research Council Linkage grant of $163,000 funded the study. Other strands of this research close to being completed include a comparative study of the mental health of the babies, and a study of their physiological measures as they interact with the music therapist.
The researchers hope to replicate and expand this study in the future in order to consolidate their findings.
The researcher who had the task of singing and interacting with the sick infants was Helen Shoemark, a Senior Music Therapist at Melbourne's Royal Children's Hospital and an honorary Research Fellow at the Murdoch Children's Research Institute.
Ms Shoemark, who is completing her PhD at the National Music Therapy Research Institute at the University of Melbourne, says: "I'm now analysing the specific characteristics of the therapy so that it can be applied by other therapists in this field."