Real-ear characteristics of the ALGO2 acoustic transducer assembly.

Clinical reports regarding the use of the ALGO2 neonatal automated auditory brainstem response (AABR) screening device have been concerned only with issues of sensitivity and specificity. This study was undertaken to evaluate how couplers and their placement affect the ALGO2 click spectral properties. Although not recommended by the manufacturer, substituting less expensive, uncalibrated couplers for the standard earphone may be a tempting alternative in clinical practice. Click spectra of an ALGO2 were analyzed with a real-ear system so that comparisons could be made between probe tips and the standard coupler. In addition, ALGO2 screening data from neonates using the standard earphone and a substitute probe tip were compared. The results are in agreement with the manufacturer's specifications when the ALGO2 is used as prescribed. However, with probe tip couplers, SPL values were markedly increased, particularly as insertion depth of the probes varied. The neonatal AABR results show that coupler type and placement can also produce inaccurate screening evaluations and erroneous conclusions.