Cox, Johnson, and Alexander (2012) report cochlear dead regions (DRs) occur when inner hair cells at a given frequency are lost or malfunctioning. Previous publications have suggested hearing-aid high-frequency gain should be attenuated in the presence of high frequency DRs.
Precondition for a VdS approval procedure, among others, is proof of a certified quality management system in accordance with DIN EN ISO 9001 for the manufacturing facility of the product.
Type Approval or Certificate of Conformity is granted to a product that meets a minimum set of regulatory, technical and safety requirements. Generally, type approval is required before a product is allowed to be sold in a particular country, so the requirements for a given product will vary around the world.ype Approval is not a term confined to a particular industry. Type Approval requirements exist for products as diverse as marine equipment, mobile phones, automotive industry, or medical equipment. Type approval simply means that the product is certified to meet certain requirements for its type, whatever that may be.