Lessons

9d - The Sound Map

Posted by Helen St Clair Tracy in Level 9 - Dorsal (2)
Published: 08/09/2021, 12:56am | Updated: 26/09/2021, 10:28am

The lessons in this level (Level 9) have been written from many first-hand accounts shared by people who look after children who have a type of CVI where their posterior parietal lobes have been affected. This is therefore more subjective than our other lessons, but is the subject of ongoing research. As the accounts have been so consistent, we wanted to share them, because the understanding they give us lets us make simple adjustments to help many people, especially those unable to communicate their challenges, as is the case for young children and those with limited communication skills.

  • Question: Why have we got a lesson on sounds, when this is a website about vision?
  • Answer: Because many with CVI also have difficulty processing sounds. To explain...

For a moment, stop what you are doing and listen to the sounds you can hear around you...

What can you hear? Maybe a clock ticking, the quiet processor in your computer, white noise from a machine, footsteps in the distance, talking, a door closing or traffic.

Please can you write them down or make a note of them for a little exercise we are going to do?

For a small exercise, please can you make a note of the sounds you have heard around you?For a small exercise, please can you make a note of the sounds you have heard around you?

For each sound you have noted, think for a moment...

  • How far away are is it from you?
  • What direction is it coming from?
  • How do you know what it is?

You know what each sound that you've identified and noted is, because your successfully completed a recognition process. That recognition process involved matching the sound heard with your memory of the same or similar sound in your mind, so each sound can be successfully identified.

That identification process is only possible because all those sounds on your list were mapped. We are using the term 'mapped' in the same way as explained in the three previous lessons, but here in relation to sounds.

The sounds have been mapped around you, in relation to the direction your body is facing, not just your head and ears.

This sound mapping process takes place in the parietal lobes.

The sound mapping process takes place in the parietal lobes.The sound mapping process takes place in the parietal lobes.

We have mentioned the parietal lobes a great deal in these lessons, and introduced them back in lesson 1c. The area at back of the parietal lobes, called the posterior parietal lobes, is one of the main visual processing centres of the brain.

The sound mapping process has many similarities with the vision mapping process, and both are processed in the same region of the brain.

Sound Mapping Process

  • 1. The sounds, once registered by your hearing systems are mapped, and so located, hopefully to the correct positions around you, so you know if they are near or far, and roughly from which directions they come from, including behind you. The primary reasons for this process is to keep you safe.
  • 2. The sounds that have been mapped in this way are given attention, so you then become aware of them.
  • 3. Once the sounds have been given attention, they can be compared with the memory files in your mind so that you can recognise them, as we have explained in lessons 2g Memory and 2h Recognition in relation to vision.

This process has a sequence, so if something is not mapped by the mind, then attention is cannot be given to it, and without attention, as far as your mind is concerned, it is not there, and not there, means there is nothing to recognise nor respond to.

Please note: The difference in the time of arrival of sound to the two ears is what allows sounds to be located. This means that those who are deaf in one ear find it difficult to locate where sounds are coming from. This difficulty is different. It is also better recognised.

Processing of sounds, similar to vision, has an order.  To be recognised, a sound must first be mapped, as only sounds that are mapped are given attention.Processing of sounds, similar to vision, has an order. To be recognised, a sound must first be mapped, as only sounds that are mapped are given attention.

Next we are going to give you a sound to identify, to make you really think about that process. Because we are alerting you to it, and you know it is coming from the device you are reading this lesson on, it will be mapped and you will know where it is coming from - but what is it?

As you try to identify it, think about that your brain is doing. Your brain is searching for the matching sound in your memories, so you know what it is.

The reasons we are asking you to do this, is because the recognition is the only part you are normally consciously aware of - the rest are non-conscious brain processes.

Think about the process going on in your brain as you try to recognise this sound (what it is at the end of this page).Video Link: https://vimeo.com/598149398

But what if it that process is not working so well?

If a sound is not mapped, it is not given attention, so as far as the person is concerned, that sound does not exist... They are not aware of it, which is the same as not being able to hear it or being unresponsive, even though the hearing systems may be working typically.

It is the same with the visual difficulties from this part of the brain, where a person is not aware of things around them visually if they have not been mapped. We explained this in lessons 9a, 9b & 9c.

But what if both the sound map and the visual map are not processing well?

Sound processing difficulties in children with CVI are commonly reported, particularly:

  • Not being able to look and listen at the same time.
  • Not being able to locate where someone is calling from
  • Seemingly variable levels of hearing, where sometimes even loud things are not heard, yet at other times the person may seem hyper-sensitive to sounds.
  • Inconsistent responses to the same sound, so one time it may be ignored, and another time, even just a few seconds later, it may cause an extreme reaction.
  • Easily confused and frightened by sounds

One girl we know needs people to turn their back on her so that she can listen to what they are saying. If they were facing her, she could not hear them. We explained this in a short page called Not Looking to Listen.

The child, seated, needed the adult to turn his back on her whilst he was talking, so that she could hear him.The child, seated, needed the adult to turn his back on her whilst he was talking, so that she could hear him.

What has been described when both the sound and vision maps are not processing typically is a sort of competing element, where a person can hear or see, but not always both at the same time. This is a particular problem where an environment is complex or challenging, for example somewhere busy and noisy.

Busy noisy places will put demands on both the sound and vision maps and be challenging.Video Link: https://vimeo.com/598756668

Anywhere busy and noisy is going to be difficult, putting demands on both maps.

Simple, quiet and calm will be much easier.Video Link: https://vimeo.com/598862409

If the sound map is not processing typically, in combination with CVI, specifically where the vision map described in this level (9) is affected, there can be some tricky complications:

  • The identities and meanings of sounds are not learnt, because they are neither consistently heard nor clearly linked to a corresponding image. This can lead to complex learning difficulties and delays.
  • Sounds are therefore not recognised, because they could not be learnt.
  • Sounds are not calibrated. Your brain is able to filter out sounds you know well from the background sounds, so you are not constantly being distracted by ticking clocks, or footsteps, or traffic noise. This calibration process is needed to distinguish what the brain has 'learnt' and associated with what is normal, boring and can be ignored, and what needs attention, like the doorbell or a car horn. If the meaning and significance of sounds have not been learnt, then the process of their calibration is directly affected. This may mean that sounds can become confusing and frightening. The calibration process is explained briefly with audio examples in our page One Thing At A Time and in more detail on our pages Attention & Its Calibrations (links at bottom of page).
  • Sounds not correctly mapped, may appear closer than they are, or may 'pop-out' suddenly, both causing frights and anxiety.
  • For all the reasons above, learning language can be affected, in some very severely.

Issues with the sound map are a problem, combined with simultaneous similar issues with the visual map lead to a complex cocktail of difficulties.

The following paragraphs on Targeted Support, Visual Behaviours and Self Referencing relate specifically to children affected by both sound and visual processing issues, not sound processing issues alone.

Targeted Support

  • Try to keep the complexity of the surroundings, clutter, movement and noise to a minimum.
  • Develop knowledge using a step-by-step, one thing at a time approach (see Further Reading)
  • Regularly stop and re-evaluate the child's surroundings. Something you may not be aware of, like a lawnmower outside, may mean the child can no longer learn in class, or may be getting scared.
  • Use language! For the more able children, get used to talking about what they can see and hear, to learn what is, and what is not visible and / or audible. For those without language, directly link single experiences to consistent, single, salient words.
  • This complex combination can mean a child may quickly, and sometimes very unexpectedly, become overwhelmed, even having a CVI Meltdown, so always ensure there is a way they can take a break somewhere quiet, clear and calm.

Visual Behaviours

The child may sometimes, but not necessarily always:

  • Appear to ignore people when being spoken to.
  • Not be able to see things when they are listening, which can look like they are not paying attention or are distracted. They are being distracted from what they are meant to be looking at... They are trying to listen!
  • Seem like they can't hear and other times appear overly sensitive to sounds
  • Dislike noisy places.
  • Have sudden outbursts.

Self-Referencing

Due to the calibration issues, what the child hears may be completely different to what you hear. Please take a few minutes to listen to the clips on the short page One Thing at a Time (link below), where this is explained.

This combination can affect all aspects of learning, making the difficulties extremely dynamic. A child may respond well to something or someone one day, and appear to ignore them the next, or become stressed or agitated. Learning to understand their neurologically dual sensory impaired world is extremely difficult for those unaffected. Enormous patience is needed.

Checklist:

Before you move on to the next lesson, please check you understand:

  • Which part of the brain the sound map is processed in.
  • Why children with CVI may also have issues with the sound map.
  • The way sound is processed in the correct order - map, attention, recognition, and meaning.
  • Complications due to the sound map not being processed typically.
  • The challenges of both the sound map and the visual map not processing typically at the same time.

Next lesson Level 9e Dorsal (2) Parallel Processing

Further reading is not necessary to move on to the next lesson, but if interested you may enjoy the following:

Cerebral Auditory Impairment - Explaining sound processing difficulties in children with CVI, with many first-hand accounts.

CVI and Cerebral Auditory Processing Disorder (CAPD) Paper

One Thing at a Time

Attention & its Calibrations

The sound is a skipping rope.Video Link: https://vimeo.com/598149398

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At CVI Scotland we are devoted to helping people understand cerebral visual impairments, and together working towards developing the understanding of this complex condition.