Reverse-slope hearing loss (RSL) affects mainly the lower frequencies. One of the main causes of RSL is genetics. Wolfram syndrome, Mondini dysplasia, and inheritance through a dominant gene have all been identified as sources of RSL. Certain diseases have been implicated as well, mainly those affecting the hair cells, which are responsible for sending sound information from the inner ear to the brain. Examples include sudden hearing loss, Ménière’s disease and viral infection. The third most common source of RSHL is anything that causes a change in the pressure of the endolymph, a fluid in the inner ear. This includes things such as spinal or general anesthesia, intracranial hypertension, and a perilymphatic fistula. It is difficult to recognize, diagnose, and treat as most health care professionals will be caring for high-frequency loss or simply have never heard of it. Also, people who are born with the condition may not be aware that they have it, therefore never seeking help. Symptoms include difficulty understanding speech on the phone, as volume normally comes from lower frequencies, ease understanding women and children but not men, and inability to hear low-frequency environmental sounds such as thunder and a refrigerator humming. RSL can be difficult to treat as manufacturer-recommended hearing aid settings are meant for high-frequency hearing loss - which millions of people have. It gets it's name from the fact it shows the opposite graphical representation on an audiogram to the more common high-frequency hearing loss. It's distinct appearance looks the opposite of a ski slope, starting in the lower-left-hand corner and sloping upward steeply. Source
