What Are Reverse Slope Hearing Aids

Reverse slope-hearing loss is an unusual condition distinguished by poor hearing specifically in the lower sound frequencies. Often, a person living with this type of hearing loss can possess normal hearing for high sound frequencies, creating an unusual hearing conundrum that can be managed with the right type of hearing aid. The cause behind reverse slope hearing loss could be hereditary, a condition passed down the generations. Alternatively, it may be linked to certain medications, childhood illnesses or indeed the onset of Meniere’s disease. Loss of hearing can be measured using an audiogram, which can highlight all kinds of conditions. By far the most common type or shape of audiogram is often referred to as a ‘sloping’ loss, where the audiogram indicates hearing is good within the lower frequencies then drops away as higher frequencies are introduced. The opposite can be said for reverse-slope, where the hearing loss is very apparent during the low frequencies but the results shown on the audiogram improve sometimes quite dramatically as higher frequencies are tested. As opposed to those with high frequency hearing loss, many people who live with reverse slope hearing loss may be able to hear speech reasonably well; but need a boost of low frequency amplification for improved environmental awareness. At those frequencies where there is hearing loss, the degree of loss can be mild, moderate or severe; and all require individual assessment to help manage the condition and be paired with the most appropriate hearing aid. Fitting a hearing aid where there is low frequency loss only can be tricky, as many products are specifically geared to amplifying the more common high frequency losses. This is particularly true of products using 'open-fit' tubing solutions. When a non-occluding open fitting is used to fit a hearing aid to the ear, low frequency sounds are allowed to pass into the ear relatively unaffected or un-amplified - which is great for a predominantly high-frequency loss, but not ideal for a reverse slope audiogram. Where there is moderate or severe low frequency loss a more occluding mould or dome is required. While Hearing Direct primarily caters for high frequency loss, there are some products such as the HD430 RIC which can be programmed for low frequency loss.

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