The language development starts at a very young age. To get in touch with language, good hearing is important. That is why, around the fifth day after birth, at the same time of the heel prick, a hearing test will be executed by an employee of the GGD. This is a simple test where the baby gets a small cap in both ear canals. This cap sends sound waves to the hearing organ, which sends signals back if the baby can hear. The device measures these signals.
It sometimes occurs that the test does not work the first time. Moisture in the ear is often the cause. To make sure the chance for this to happen is small, you should not bathe your baby the day before the test. If the test does not succeed, it will be repeated a couple of days later. If the test is not succesful for one or two ears, a reference for further examination in an audiological center will be made via the general practitioner.
For more information you can consult the website of the RIVM.