Investigation of a significant increase in referrals during neonatal hearing screening: a comparison of Natus ALGO Portable and ALGO 3i.

Objective: Neonatal hearing screening programs in Flanders and the Netherlands use Natus ALGO screening devices. Since 2006 in Flanders and 2009 in the Netherlands, both programs have replaced the older ALGO Portable devices with the newer ALGO 3i devices. However, in both countries, ALGO 3i devices have a significantly higher rate of referrals than ALGO Portable devices. In Flanders, the refer rate has more than doubled with the switch to ALGO 3i devices. In the Netherlands, screening centers which used ALGO 3i devices also showed a significant increase in referrals. In both countries, the percentage of children diagnosed with permanent hearing loss remained approximately the same.
Design: A technical comparison of both device types was carried out to identify possible causes for the increase in referrals. The stimulus output of two ALGO Portable and three ALGO 3i devices was recorded and analysed for stimulus level, spectral properties, and stimulus irregularities.
Results: ALGO 3i devices stimulate at a peak level 4.6 dB lower than ALGO Portable devices, have a different stimulus spectrum and show unexplained stimulus irregularities during 4% of the stimulation time.
Conclusions: A number of technical differences were found between both device types which could explain the increase in referrals.