According to research published in the National Library of Medicine, the use of a hearing aid can provide several notable benefits to someone struggling with tinnitus.
First and foremost, if the tinnitus is related to hearing loss, the hearing aid will effectively 'overpower' the condition. Because the user can now focus more on external sound, their tinnitus becomes less of a distraction. Given that hearing loss related tinnitus is usually tied to a condition known as auditory deprivation, it makes sense that addressing said deprivation can help lessen the severity of the condition.
Additionally, the stimulation provided to the auditory nerve by the hearing aid can occasionally 'reprogram' it, making it less likely to misfire in the future. In plain English, the hearing aid helps the auditory nerve stop malfunctioning by providing it with the input it expects. This, in turn, helps restore things to some semblance of working order.
Some hearing aids also include functionalities such as sound masking, adding a soft layer of white noise to drown out the condition. This is typically configured through a companion app, though some hearing aids may also feature physical controls for that purpose.
The above benefits are ultimately all tied to the fact that the right level of stimulation can effectively retrain the brain to treat tinnitus as background noise, and eventually ignore it altogether — a process known as habituation.