Background and aims NICU’s environment is rich from an acoustical point of view. Long-termeffects of exposure to repeated noise in preterm’s neurological and sensorial developmentis of concern.
We aimed to analyse the acoustic environment of the NICU, the types ofsounds present in it and their characteristics (both intensity and frequency).
Patients and methods Ten recording sessions were carried out. Duration of acquired data:108.7 min. Two microphones connected to the Olympus LS-5 Linear-PCM Recorder were used. One microphone was placed inside the incubator; the other, outside.
Results More than 65 different sounds were found. We divided them intoacoustically homogeneous groups:
1. Tones (mostly equipment alarms), were present in 21% of the totalrecorded time.
2. Vocalisations (with a lot ofdifferent subclasses here: speech, cry, laugh, cough... both from infants and adults) in 63%.
3. Other (all the other sounds: equipment moving, respiratory devices, caregiving tasks, etc.) in 70%.
Average/Maximum sound intensity was 54/72.3 dB inside the incubator and 51.6/69.7 dB outside.
With respect to the spectral domain, the fundamental frequencies of alarmsare mostly around 1.5 kHz, and the content of vocalisations can be observed upto 8 kHz. The group other is diverse, since it contains lower- andhigher-frequency sounds, and also sounds spread over awide frequency range (e.g. ventilation noise).
Conclusions 1. In our NICU noise levels exceeds recommendations.
2. There is a large and diverse set of sounds; vocalisations are the most common.
3. Noise inside the incubator is higher than outside it.