For which of the following instruments do national standards or uniform performance standards for calibration exist?

Pure tone audiometers have established national standards and uniform performance standards for calibration due to their critical role in hearing assessments. These standards ensure that the equipment used to deliver pure tone stimuli is accurate and reliable, which is essential for diagnosing hearing impairments. For pure tone audiometers, calibration must occur regularly and follow specific guidelines to maintain the consistency and accuracy of hearing threshold measurements.

While other instruments, such as OAEs (otoacoustic emissions) and ABR (auditory brainstem responses), are vital in the audiological assessment process, they may not have the same level of universally mandated calibration standards comparable to those of pure tone audiometers. Therefore, while these other tools are calibrated for accurate function, the depth and specificity of the standards may not align with those required for pure tone audiometers. This distinction underscores the importance of pure tone audiometers in clinical practice and the necessity for uniformity in their calibration standards to ensure valid patient outcomes.