Functional screening assessment. A flow chart of the screening process concerned with assessing potential participants against the inclusion criterion governing the acceptable level of function in the impaired ear. If aidable, functional performance will be assessed while the NH ear is occluded using an earplug and circumaural mufflers. Should the level of function still fall outside criterion, performance will be assessed again but while a masking noise is also presented to the NH ear. Individuals who cannot be aided, either because it is deemed clinically inappropriate or because it is not possible fit an aid (e.g. few or no measurable audiometric thresholds), will be eligible for inclusion. NH: Normal Hearing.