The role of the inner ear in Dyslexia and ADHD

Understanding how the vestibular works and, more importantly, how it affects our functioning makes it easier to understand why it is implicated in syndromes like dyslexia and ADHD. It also helps to explain why and how certain, specific movements improve vestibular functioning and make positive differences to children struggling at school.

The role of the inner-ear or vestibular system underlying cognitive and behavioral disorders and their treatment has been studied by many gifted clinicians and therapists. However, the role of both the inner-ear and cerebellum (the ‘small brain’ at the base of the larger cerebrum) in determining ADHD dates back to the pioneering dyslexia research of Frank and Levinson initially published in 1973, and then evolving over four decades. By recognizing that dyslexia and ADHD are significantly overlapping disorders characterized by imbalance and poor coordination, Levinson proposed that both disorders stem from one common impairment– a signal-scrambling dysfunction of inner-ear/cerebellar origin. His ADHD data and concepts were published in numerous papers and books. Significantly, these concepts are consistent with the cerebellar research of Noble Laureate Sir John Eccles and outstanding others as well as inner-ear clinicians called neurotologists, hence gaining their support.

Levinson explained the ‘signal-scrambling’ as follows: “Just imagine the symptoms induced by spinning until dizzy. When dizzy you can’t properly read, write, speak, recall, think, plan, concentrate, orient, balance and coordinate. It’s as if the signals transmitted to varied brain structures are ‘dizzy’ or scrambled and so cannot be normally processed. They thus induce temporary dyslexic or ADHD-like states. It’s the dizzy or scrambled signals that are considered etiologically most important, not necessarily the conscious sensation or experience of dizziness which may lessen, disappear or be absent. “This analogy also explains how and why signal stabilizing medications, including inner-ear enhancing antihistamines and stimulants, are so effective in treating both dyslexia and ADHD. And it further explains the efficacy of anti-vertigo therapies in preventing the inner-ear triggered reading reversals (“space dyslexia”) and impaired concentration, orientation and balance (“space ADHD”) in orbiting astronauts.

There isn’t enough recent research to support Levinson’s findings but a 2013 study by Jean Hebert and colleagues published in Science provided important experimental evidence that a genetically induced inner-ear impairment in mice was linked to hyperactivity and thus might cause ADHD in humans.(http://www.einstein.yu.edu/news/releases/932/inner-ear-disorders-may-cause-hyperactivity/

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Martin Doherty, writing for The Conversation, says that at the age of about four, children reach important milestones in brain development.

One of these is a huge improvement in understanding others’ thoughts and feelings. This is the start of empathy. Another is in spatial thinking—understanding how objects are positioned and related. This is the beginning of the ability to read maps.

Martin and his colleague, Catherine Sayer, conducted a study with 175 two to five-year-olds to explore how children are able to use scale models to figure out where something is in the real world. At about four, children are able to use a scale model of a room to work out where something is. We thought that this might result from children’s understanding of how one thing can represent something else. But we actually found that four-year-olds’ ability to use scale models came from their spatial abilities.

At the same age, children start to understand that someone’s behaviour is due to what that person believes, not necessarily what is really the case. This has interesting consequences.

If you’ve played hide-and-seek with young children, you may have noticed that they aren’t always very good at it. They love the ritual of looking in all the wrong places first, but beforehand they may tell you where they are going to hide, hide in the same place every time, or not be especially hidden.

After their fourth birthday, they get much better at hide and seek. They understand that the seeker looks in the wrong places because they don’t know where the hider is.

At about three to four children also start to tell lies. They realize they can make someone believe something that isn’t true.

Understanding symbols

Martin’s earlier research with fellow psychologist Josef Perner suggests that four-year-olds don’t just start to understand how others’ minds work. Figuring this out is part of the development of an understanding of “representation”—that symbols, like thoughts, words, or pictures, can be used to stand for something else.

Children start to think about how words relate to objects. This means, for instance, knowing that “animal” can refer to something you already have a name for, such as “rabbit”. This might help children learn the new word.

Their ability to use a understand the components of pictures also improves around this age. Very young children use a lot of trial and error to complete a jigsaw, picking up random pieces to see if they fit. By the time they are about four years old, they start to use the picture as a guide, trying to connect lines and match bits of colour, while checking the guide picture on the box lid.

Developmental experiments

Another ability children develop at around four is using scale models. A classic set of developmental experiments involved a model of a regular household room. The real room had typical furniture—sofa, table, cupboard and so on—and the model had miniature versions laid out in the same way.

Children were shown where something was hidden in the model and told to find an object hidden in “the same place” in the room. Children of around four can find the object using the identical layouts. If shown a sticker under a particular chair in the model room, for example, they can go straight to the “same” chair in the other room. This is the fundamental understanding required to read maps.

Adults see scale models and maps as representations. Maps represent a town or a country. A scale model of, say, the Eiffel Tower represents the real thing. At first, Martin suspected children’s ability to use scale models is more evidence of understanding representation at this age.

He was wrong. Instead, the researchers found that this ability is based on a development in children’s spatial abilities that also occurs at about four. This is the ability to think about spaces and where objects are within them. Spatial abilities help with maths skills, and good spatial ability is linked to an interest in science, technology, engineering and mathematics.

Their experiment was simple. They compared the model room task with a test of understanding how representation works. The two abilities develop around the same age, but they found they were not related. Children who could do one task couldn’t necessarily do the other.

They also had a test of purely spatial ability. Children who passed the model room task also passed the spatial task. So it looks like the model room task relied on children‘s spatial thinking.

They don’t yet know why two important but apparently unrelated abilities arise at the same time. Perhaps it’s related to changes in the growing brain at this interesting age.

Provided by The Conversation.

Image supplied by Freepik.