Ana Isabel Sanchez Jimenez is a PhD student in Professor Andrew King’s lab at the University of Oxford. Her studentship began in 2019. This studentship has been fully funded by the Peter Jost Foundation.
Spatial hearing allows someone to detect where a sound is coming from. Accurate spatial hearing has clear survival value – for example, it tells you the direction of an approaching car when you’re crossing the street. It’s also important for understanding speech in a noisy environment, or for picking out a particular voice in a crowd.
Spatial hearing involves being able to detect differences in the timing and loudness of sounds between the 2 ears. This becomes more difficult, and less effective, when a person’s hearing loss is more severe in 1 ear than the other.
Previous research into temporary conductive hearing loss in 1 ear (which occurs when there’s a problem in the middle or outer ear which prevents sound getting into the inner ear) shows that training can improve someone’s ability to tell where a sound is coming from. This suggests that the brain can be trained to compensate for a temporary conductive hearing loss.
However, this research was carried out in a quiet laboratory setting, so we don’t know whether it could also help people to locate sounds in more natural listening environments. It’s also important to find out whether training could help people with sensorineural hearing loss in 1 ear. This type of hearing loss is:
- caused by damage to the hair cells in the inner ear
- and the most common type of hearing loss.
Ana aims to understand how the brain adapts to hearing loss in 1 ear and whether training can help to improve how accurately people with this ‘asymmetric’ hearing loss can locate sounds. In particular, Ana will investigate whether the changes in the brain that occur in quiet listening conditions also occur under more challenging, noisy listening conditions. In addition, she’ll examine whether training can improve the ability to locate sounds when someone has a partial sensorineural hearing loss in 1 ear.
Ana will measure how accurately people can locate sounds in a realistic and noisy environment. The participants will then wear 1 ear plug (to simulate a hearing loss) while they do daily training. Ana will assess whether their ability to tell where a sound is coming from improves after training, as happens in quiet listening conditions.
Ana will then repeat the same experiments in ferrets. She’ll measure how nerve cells in the hearing parts of the brain respond to sound in these animals. This will help to reveal the changes that occur in the brain as a result of the training, in order to better understand how the recovery in spatial hearing happens. In another group of ferrets with sensorineural hearing loss in 1 ear (the type of hearing loss most often experienced by people), Ana will measure their ability to locate sounds and investigate whether this also changes after training.
If the results of this project show that the brain can be trained to better locate sounds, even in noisy, ‘real life’ environments, this would suggest that people with hearing loss in 1 ear could gain real-world benefits from this training. The results will also help us to understand how hearing loss and training can shape the brain, and highlight improved strategies for treating people with hearing loss that affects 1 ear more than the other.