The University of Southampton

Author: Megan Green

Beyond Hearing Aids

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Having grown up with mild to moderate bilateral sensorineural and conductive hearing loss, I have always worn hearing aids. This sparked an interest in audiology and hearing technology which has inspired me to research the intricacies of cochlear implants, particularly as we will be learning more about this later in the module.

So, what is a cochlear implant….

A cochlear implant (CI) is a device that allows people with severe to profound hearing loss to experience sound by transmitting electrical signals via the auditory nerve. The user interprets these sensations as sound. In contrast, my hearing aids only amplify the frequencies I cannot hear.  

A CI is composed of external and internal components, as illustrated in the diagrams below. External components include a microphone, speech processor and transmitter, whilst the surgically fitted internal components are a receiver and an electrode array.  

The mechanics behind CIs is relatively straightforward. Externally, the microphone transmits sound to the speech processor which converts sound into a digital signal. This signal is sent, using a magnet, via a transmitter to a receiver located under the skin. The receiver circulates signals to the electrode array in the inner ear that stimulates nerve fibres triggering the auditory nerve in the cochlea. As a result, the brain recognises incoming sounds. Remarkable!

MRI Scan

A helpful video on cochlear implants is below:

Whilst researching CIs, what astounded me the most was the rehabilitation process. It had never occurred to me just how difficult it would be to adjust to sounds if the user has no hearing memory and therefore struggled when sound was different to what they perceived it might be.

To understand this, I contacted a friend who is profoundly deaf in both ears since she was 21 months old.  She received her left CI at 2½ years and right CI aged 8. Her CI has hugely benefitted her communication with others and listening to music, both of which she previously found challenging.

The hardest part of her rehabilitation process was undergoing years of speech therapy to adjust to the new sounds. To adapt to the second CI, she read her schoolbook aloud only wearing the second CI. After several months she could hear properly through it. However, she found it difficult to adjust to the new directionality of sound introduced by the right CI. Unfortunately, this meant she never fully acclimatised to hearing through both CIs and for that reason she only wears her first CI.

This intrigued me further to investigate what facilitates the rehabilitation process.

According to the British Cochlear Implant Group, rehabilitation is a structured programme, known as auditory training, involving exercises and a Speech and Language Specialist. This helps users to interpret and differentiate sounds, as well as translate words into speech.

Whilst my friend was unable to recall her auditory training, another blog highlighted strategies for successful rehabilitation:

  • Commit to daily exercises incorporating them into everyday activities (e.g., listening and repeating categories of words in quiet and loud environments)
  • Listen to audiobooks and podcasts altering volume, speed and accents
  • Use interactive apps (e.g., Cochlear CoPilot)

My final closing thoughts …

Writing this blog has opened my eyes to the incredible resilience and dedication required by a CI user when adapting to new sounds. Furthermore, a CI is an amazing device that significantly improves the user’s quality of life and therefore socioeconomic opportunities. One paper illustrated a 21% increase in self-reported benefit as well as an average word perception increase up to 53.9% (Boisvert, et al., 2020).

Further interesting links include:

An Insight into Hip Replacements

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Inspired by the lectures on prosthetics, the impact that hip placements have on a patient’s quality and satisfaction of life really struck me. According to the arthritis society, 7% still suffer from moderate limitations and 20% report severe limitations 5 years post-surgery. Despite undergoing a second surgery, only 70% of patients reported that they were doing well.

So why are the 30% still suffering?

There are many minor reasons that hip replacements may fail:

  • Wear and Tear: Constant wearing of prosthetics can cause the joint to become loose, requiring further surgery if the problem is severe
  • Joint stiffening: soft tissues around the hip replacement become stiff and lead to reduced mobility
  • Sensitivity to metal: inserting a ‘foreign’ substance into the body  

However, unfortunately, there are more serious factors which may be at play too:

  • Aspect loosening: breakdown of the joint between implants, components and body. It can often cause the release of small particles and debris when the joint starts to wear out. The patient’s body may recognise the hip placement as a ‘foreign’ object. The patient’s immune system will identify these particles and attack them causing inflammation  
  • Formation of blood clot: increases risk of thrombosis (including deep vein thrombosis and pulmonary embolism)

A Personal View Point

Wanting to learn more, I contacted a family friend who has recently had her first hip replacement just over 5 months ago to understand what impact the replacement had on life post-surgery.. Prior to her surgery, she lived in discomfort for a long time, but recognised that her hip replacement had an extreme benefit on her quality of life (e.g. her low back pain  has reduced and she is able to sleep better. Recently, she had a second hip operation and is currently recovering. After having the second surgery, she remarks on the great benefit of the first hip replacement on her flexibility and mobility.  

However, despite the positives, she commented that the rehabilitation process is long, frustrating and slow. Your daily routine is disrupted from having to always sleep on your back, being unable to drive or exercise and work being impacted if you are unable to work from home.  Moreover, whilst she was happy with her access to pain relief, she suffered adverse events on opioids of constipation, which she argued was more painful than the hip operation itself.

The most interesting point we discussed was access to physiotherapy. She was fortunate enough to receive her hip replacement on the NHS, however, when comparing herself to a friend who had their hip replacement privately, she commented they had better access to in-person physio and rehabilitation help. I can’t help but think this raises all sorts of ethical issues due to socio-economics factors. But does the NHS have the capacity to do more?

My Final Thoughts ….

Further to having a discussion, there were two points that stuck out to me. I’d love to research more into the rehabilitation process from start to finish (e.g a strict exercise regime to strengthen muscles, and improve balance and blood circulation). A good link for more about this topic is: Hip replacement recovery: timeline, tips and information | Spire Healthcare  . But finally, the most provoking revelation that I encountered was the equal access to healthcare during the rehabilitation process . The final parting question I have is – why doesn’t everyone receive the same level of treatment?

Hearing Loss

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My name is Megan and I’m currently on BSc Biomedical Sciences. I love to read and play archery in my spare time. I’ve grown up with mild to moderate Sensorineural and Conductive Hearing Loss in both ears. I wear Phonax Marvel hearing aids (above) to help me navigate various environments and reduce background noise so that I can follow what is going on around me.

At birth, I didn’t pass the initial Otoacoustic Emissions test. After further testing, my parents realised I couldn’t hear properly. However, this was masked by glue ear. I was properly diagnosed with Bilateral (hearing loss on both sides) Sensorineural loss after i had grommets inserted at 18 months. Later, I was also diagnosed with permanent conductive loss due to hypermobility (not glue ear). However, the permanent conductive loss fluctuates.

You might be wondering … what is Sensorineural and Conductive Hearing Loss? A sensorineural hearing loss is caused by the loss or damage to the tiny hair cells located in the cochlear or the inner area. This means that the tiny hair cells in my cochlear can no longer transmit sound from the inner ear through the auditory nerve in the brain. Conductive Hearing Loss for me is caused by problems with the three small bones in my ear, as they do not conduct the sound properly.

The reason why I chose this module was because I am interested in learning more about how hearing aids and cochlear implants work, as well as the latest advancements in hearing technology. It’s a very personal subject to me.