Use of Frequency Compression in Severe-profound Hearing Loss Adults

Do Severe-profound Hearing Impaired Adults Perform Better in Speech Perception With Frequency Compression Switched on or Off or Fitted to Hearing Loss

The purpose of this study is to investigate the functional benefits of frequency compression vs no frequency compression or fitted to hearing loss in severe-profound hearing impaired adults with high frequency hearing losses. Thus, assessing whether hearing aids for this patient population can be adapted to improve speech perception.

Frequency compression is a feature available on some digital hearing aids, which is aimed at increasing the audibility of high frequency sounds. It works by taking sounds above a fixed start frequency and compresses it into lower frequencies where residual hearing is better.

Inclusion Criteria:

1. Participants must be over 18 years of age- This study is looking at the use of frequency compression & its effects of speech perception in adults.
2. No ear surgery that would make it impossible to fit a hearing aid- To ensure limited confounding variables.
3. No history of ear surgery within the last 12 months- To ensure limited confounding variables.
4. No history of ear infection(s) within the last 6 months- To ensure no contraindications and limited confounding variables to testing.
5. No otoscopic abnormality making it impossible to fit a hearing aid- To ensure no contraindications to testing.
6. Bilateral severe-profound hearing impairment with air conduction thresholds >71dBHL within the frequency range of 250Hz to 4 kHz- To analyse the effects of frequency compression on speech perception within this patient population.
7. Post lingual deafness, with good spoken English- To ensure reliability of speech testing.
8. Previous bilateral digital hearing aid experience (6+ months)- To ensure limited confounding variables.
9. Written consent required.

Exclusion Criteria:

1. Participants under the age of 18 years.
2. History of ear surgery making it impossible to fit a hearing aid.
3. History of ear surgery within the last 12 months.