It really depends on how the audiogram is off. If it reads worse hearing than is actually the case for a frequency, then that range will have louder than necessary treatment. Lowering the volume by the patient lowers it all, so reacting to a loud noise where you don’t need as much amplification as was prescribed lowers all the rest where you do need it, making speech understanding harder.
If the it reads better hearing than actual, then that range will have less amplification than needed. It will depend on the frequency this happens to predict what parts of speech are hit.
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