What happens when different conditions look the same, and may even have some of the same causes? Things get confused.
This paper looks as some of the confusion between CVI and a condition called Developmental Coordination Disorder, abbreviated to DCD.
The paper links to the American Psychiatric Association's paper listing the diagnostic criteria for DCD (click here to view it) which include the child's motor skills being below what they would be expected to be for their age, which may show itself in many ways including clumsiness. These difficulties start from an early age and create challenges around everyday activities like fastening buttons on clothes or participating in sports. Key to the DCD diagnosis is that the challenges cannot be attributed to another condition, for example a visual impairment or condition affecting movement like cerebral palsy or muscular dystrophy.
Question: So does that mean that technically - a child cannot have both CVI and DCD?
Answer: According to the diagnostic criteria, a child cannot have both CVI and DCD.
DCD only applies where there is no known neurological reason for the behaviours, and the neurological reasons include cerebral palsy and CVI.
This paper has an excellent short description of CVI, which is seen as a set of conditions that form the umbrella term for "all types of visual impairment due to brain damage or dysfunction" not a single diagnosis.
all types of visual impairment due to brain damage or dysfunction
This paper explains how, as very young children we instinctively reach out and grasp things in front of us, but this relies on us seeing what we are reaching for.
It gives an example of learning to catch a ball.
To catch a ball...
You see its details, you identify it, you pick it out from its surroundings, you choose it, you predict its vector, and you configure and move your hand to catch it. This multi-step process is remarkable, as the total requisite 'computing process' is performed within and throughout the brain.
If we think of the above list in terms of some of the many cogs, wheels and pathways needed for the brain to work, it only takes one of these little cogs to not be working so well for the seemingly simple task of learning to catch a ball, to become more difficult, even impossible.
A child with impairment of vision, may mis-reach, or not seem interested.
The typical development of hand to eye coordination may start off less accurately, and it may take longer, making the child miss.
But if the visual impairment has yet to be identified, the young child may seem:
Without an understanding that the child has a visual impairment, it is easy to see how other explanations like DCD, can be given.
The problem is that the challenges of accuracy of reach, and behaviours of clumsiness caused by CVI, look identical to those of children with DCD, but they have different causes.
To make it even more difficult, some reports suggest 50% of children with DCD also have ADHD (attention deficit hyperactivity disorder, click here for source), and we know that many children with simultanagnostic vision look like they have attention disorders, because of the limited control they have over their visual attention.
The paper quotes:
Current estimates suggest that as many as 3 to 4% of children aged between 4 and 6 years (i.e., approximately one student per kindergarten class) may have an identifiable visual or/and attentional deficit as a sequel to a possible neurologic lesion or dysfunction sustained around the time of birth.
3-4% might seem like a very high number. Recent official figures in Scotland have children with registered visual impairments as less than 0.1% of the overall population, so where are all the rest?
We know, that if conditions like CVI are not diagnosed and supported, the following can happen to the child:
Let us look at another statistic, to find out where all our missing children with visual impairments might be...
In England for 2016 / 2017 the percentage of children with special educational needs in schools is 14.4%.
Special educational needs is a wide umbrella term, including all of the above, and more.
Maybe that is where they are, undiagnosed, or misdiagnosed in that huge figure of 14.4%?
So, we have a complicated problem affecting enormous numbers of children.
DCD and CVI are both widely misunderstood, to make things more complicated however, they are also mixed up, which in turn means children's challenges may be attributed to the incorrect cause, which means the approaches and strategies to support them may not be sufficient, and may possibly be detrimental.
This paper tries to un-knot the two, by explaining them separately, and showing practitioners how to tell them apart, to ensure children are correctly diagnosed.
To try to understand things separately, we need to separate out what are and are not medical conditions. If something is not a medical condition it does not mean it doesn't exist, it is just understood differently, and it is important to understand why. Umbrella terms for groups of behaviours, including DCD, ADHD and ASD are not medical conditions.
CVI is a group of visual impairments that are medical conditions.
DCD is the name of a group of behaviours. It is not a medical condition, but there may be underlying medical conditions that cause the behaviours, that in many cases are unknown.
We know of families in whom CVI has been mis-labelled, in some cases as DCD, and in others as autism.
Children need an early correct diagnosis and skilled targeted support matched to the diagnosis, to avoid the development of challenging behaviours and learning difficulties. We have in depth experience of families where incorrectly labelling CVI as autism, has actually led on to the behaviours of autism because of the use of inappropriate management strategies - like a self fulfilling prophecy. We are seeing their autistic behaviours melting away now that the impact of their disordered vision has been recognised and catered for.
This is why it is so very important that children are correctly diagnosed.
CVI can look like many things, including DCD, autism and ADHD, and this paper goes into detail explaining why these mistakes can be made, and approaches taken, including expert history taking, to ensure accurate clinical diagnosis.
Many with CVI have challenges socially interacting and communicating, particularly using and interpreting gestures of body language and facial expressions. Learning, including reading, writing and maths can be difficult, and they may appear a clumsy or uncoordinated.
A simple useful list of behaviours common in children with CVI can be found in the Dorsal Stream Dysfunction Plus paper we featured in this section.
We completely agree with the paper's conclusion:
There is thus an urgent need for greater understanding of these impairments to enable better and earlier diagnosis and treatment, and optimal differentiation of CVI from the various neuro-developmental disorders especially DCD and CP, which share a similar semiology and common aetiologies.
Similar semiology and common aetiologies mean they can look the same and have the same causes, but that does not make them the same thing.
Children need the right support, and this requires the correct diagnosis.
Paper: Impact of Cerebral Visual Impairments on Motor Skills: Implications for Developmental Coordination Disorders, Chokron S & Dutton G, Frontiers in Psychology, Oct 2016
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