Early signs of hearing loss usually involve speech-comprehension difficulties in noisy environments with no discernible alteration in audiometric results – the audiometry is the gold-standard method for measuring hearing loss and consist of estimating the lowest hearing level at different frequencies. This form of hearing problem is known as hidden hearing loss (HHL) – hidden because it is not possible to diagnose using best-practice clinical tools, such as the audiogram. In fact, one person for every ten who visit a hearing clinic reporting hearing-in-noise difficulties cannot be helped because the nature of their hearing difficulties cannot be determined.
Studies conducted in animals provide a model of different neurophysiological pathologies that could be involved in HHL in humans, however research in humans remains inconclusive, and no significant progress has been made in the past 10 years. This project aimed to design and demonstrate the feasibility of three novel tests based on auditory evoked potentials (AEPs) – signals recorded from the brain that are associated with the activity of the neurons in response to sounds. The main advantage of using AEP methodologies is that they are independent from a person’s subjectivity – which is why these methods are known as objective. The three novel tests proposed in this project included: