Inclusion Criteria:  Ability to give informed consent in English In the age range stipulated for the group, i.e. 18-19 inclusive for group 1 and 30-50 inclusive for groups 2 - 4. Audiometric thresholds in the range stipulated for the group, i.e. in the normal range for their age group for groups 1 - 3 and outside the normal range for their age group for group 4. Noise exposure in the range stipulated for the group, as determined by the NESI, i.e. less than 15 units for groups 1 - 2 and 15 or more units for groups 3 - 4.  Exclusion Criteria:  Contraindications for MRI Motor impairment (for example, cerebral palsy) Cognitive impairment (for example, dementia or brain injury) Health conditions indicative of peripheral neuropathy (e.g. Type 1 diabetes).