Go simple! Do sudden sensorineural hearing loss or something like that.
Mine is on bilateral conductive/ mixed loss on a virtual patient with no eardrums or ossicles (ie. MAXIMUM conductive component; 60-70 dB air-bone gaps) and it's pretty hard! When I ask professional audiologists what they would do in such a case, 3 out of 4 said "mark it as a masking dilemma and be done with it" 🙁 Obviously I don't get to take such a simple approach.
Consider that your research doesn't have to be groundbreaking but it DOES have to be consistent with "the field". Good luck!