Evaluation of a linear TEOAE protocol in hearing screening of neonates: feasibility study [Valutazione di un protocollo TEOAE lineare nello screening audiologico neonatale: studio di fattibilità.]

The audiological screening of newborns based on recording TEOAEs--the expression of anatomical-functional integrity of the cochlea--has unanimously gained importance. The prevalence of severe of genetic or congenital hearing loss in the healthy infant population and in the population at risk for audiological disorders, as well as the consequent psycholinguist and socialization problems such children have to deal with, have led the authors to set up a preliminary protocol for the audiological screening of neonates. The purpose of this protocol is to improve the feasibility of applying such a program. To this purpose, the preliminary protocol called for the recording of the TEOAE in both non linear (NL) and linear (L) modes. Examination was performed in 347 newborns (30% of all the children born during 1997) the second day of life and during spontaneous sleep. The ILO 92 was used for the screening. The results obtained with the two methods were statistically compared using the 9 parameters considered response indicators. Using the linear method of a function-window and improving the signal-to-noise ratio, the study showed a significant difference in the quality of the TEOAE using the linear method as compared with the non linear method, although this did not modify response reliability. This lead to the definition, through free distribution statistical analysis, of broader than normal criteria by which to evaluate the responses evoked with the L method. All this is aimed at increasing system specificity and reducing the number of false positives which feeds family anxiety.