Yin and Yang: Both make the whole

Audiologist, David Crowhen shares why hearing loss in one ear is not simply half the impact of hearing loss in both ears.

Oscar Wilde once said, “Experience is simply the name we give our mistakes”.1 

Indeed, a learning for me during my career in Audiology, recently corroborated by emerging research,2 is that hearing loss in one ear is not necessarily half the impact of hearing loss in both ears!

Clients who helped me learn that ‘both make the whole’

I have had the privilege of working with many hearing impaired clients over the years, all of whom I believe have helped me become a better Audiologist. 

If you ask me the ones I remember most (and to be fair, I’ve seen a fair few … as I’m not as young as I used to be!), interestingly, two clients CROS my mind. 

  • The first, a lady who experienced a sudden, profound loss in her right ear whilst retaining normal hearing on the left. After several years of persevering with the well-established impacts of unilateral hearing loss (UHL), including challenges communicating in noise, at a distance, in quiet and when localizing sounds3-5, she sought help. 

    We partnered to fit an Audéo Smart on the left and wireless CROS transmitter on her right ear. Upon activating the system and speaking on her right (CROS) side, tears started streaming down her cheeks.

    She told me that the profound hearing loss in the right ear had removed part of her body/existence on that side (a little bit like a missing limb) and hearing sound again from that side (albeit in the left ear) had, for her, restored an increased awareness of sound on that side of her body. 

    Hearing in both ears, she felt whole again, physically.

  • The second client was a very young women who recounted her teenage years.  Inherently gregarious by nature, she described how she was deemed a ‘snob’ by her peers because often she didn’t respond when budding friends were speaking to her at noisy parties, especially if they were on her non-hearing (left) side.

    This was a number of years back now and the only option at that time was a wired CROS system, which, despite being less than discreet, we decided to trial.  For this client, the benefit of being able to finally hear people talking from the left side far outweighed any cosmetic concerns she had wearing the wired CROS device.

    Hearing in both ears, she felt whole, socially. 

How do we know we have helped?

While the benefits of binaural amplification for clients with aidable hearing loss in both ears are often immediately evident, they may initially be more subtle for those with unaidable UHL. 

Indeed,  Mueller & Hawkins6 reported that such clients sometimes find it challenging to reliably report whether their CROS system is operational.

Real-ear verification supports optimal outcomes .. including for your CROS/BiCROS fittings

Probe microphone measures therefore present an ideal, objective way for verifying any fitting, including assessing whether a CROS/BiCROS system is functioning well and overcoming the head shadow effect.7

Further support for utilizing probe microphone measures comes from MarkeTrak findings8-9 for conventional hearing aid fittings. They found that:

  • Clients receiving best-fitting practice experience greater reduction in hearing handicap compared to those that don’t.
  • Clients receiving both verification and validation measures required on average 1.2 less visits compared to those that did not.

Want to CROS your T’s and dot your I’s with your fittings for clients with UHL?

To support best clinical practice, check out the CROS P verification guide that I had the privilege of developing with my HQ colleagues Jane Woodward, Michael Preuss and Jacqueline Drexler.10

To learn more about CROS P, a Paradise solution for UHL, we invite you to check out our product page.


  1. Brainy quotes. Oscar Wilde. Retrieved from https://www.brainyquote.com/quotes/oscar_wilde_105029, accessed September 30, 2021.
  2. Pierzycki, R., Edmondson-Jones, M., Dawes, P., Munro, K. J., Moore, D. R., & Kitterick, P. T. (2020). Associations between hearing health and well-being in unilateral hearing impairment. Ear and Hearing, Vol. 42(3),520-530
  3. Lieu, J.E., Karzon, R. K., Ead, B., & Tye-Murray. N. (2013). Do audiologic characteristics predict outcomes in children with unilateral hearing loss? Otol Neurotol, (9), 1703-1710.
  4. Snapp, H. A., Holt, F. D., Liu, X., & Rajguru, S. M. (2017). Comparison of speech-in-noise and localization benefits in unilateral hearing loss subjects using contralateral routing of signal hearing aids or bone-anchored implants. Oto Neurotol, 38(1), 11-18.
  5. McKay, S., Gravel, J. S., & Tharpe, A. M. (2008). Amplifcation considerations for children with minimal or mild bilateral hearing loss and unilateral hearing loss. Trends in Amplification, 12(1), 43-54.
  6. Mueller, H.G. & Hawkins, D. B. (1992). Assessment of fitting arrangements, special circuitry, and features. In Mueller HG, Hawkins DB, Northern JL, eds., Probe Microphone Measurements: Hearing Aid Selection and Assessment. San Diego: Singular, pp: 201-225
  7. Pumford, J. (2005). Benefits of probe-mic measures with CROS/Bi-CROS fittings. The Hearing Journal, Vol. 58(10): pp.34-40.
  8. Kochkin, S. (2011a). MarkeTrak VIII: Patients report improved quality of life with hearing aid usage. Hearing Journal, Vol. 64(6): pp. 25-32.
  9. Kochkin, S. (2011b) MarkeTrak VIII: Reducing patient visits through verification and validation. Hearing Review, Vol. 18(6):10-12
  10. Crowhen, D., Woodward, J., Preuss, M. & Drexler, J. (2021). CROS P Verification Guide. Retrieved from Phonak Target Desktop Fitting Overview | PhonakPro, accessed September 30, 2021.

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