On the developmental quotient

By 12th October 2018 No Comments

One of the things newly diagnosed NKH parents worry about is severity. There is a range: Severe is at one end. Severe means that neither mutation is producing any protein that can be used by the body. Any protein that is made is probably unstable and falls apart to be recycled. Severe is what we’re primed for – disabled, seizures, developmental delay, early death. No walking, no talking, not eating. Perhaps smiling – a developmental milestone usually hit in the first few weeks – that’s the total brain development we’re told to expect of a severe child.

At the other end, there’s attenuated – that’s a whole different kettle of fish. Some children you wouldn’t even know have NKH. They’re walking and talking and going to school and are picture perfect (I met a boy who had very mild NKH in March. I literally couldn’t stop staring. I wanted to hug him, but as a stranger to this teenage boy, I refrained). It steps down in degree’s from there. Walking and running (or sometimes non-mobile) and/or talking up a storm (or non-verbal) and/or eating (or bolus only). There are a lot of other issues, too. ADHD, severe behavioural tantrums, autistic like behaviours, hyperactivity movement disorders (dystonia, chorea, ataxia).

As I understand it, it’s a huge range split across three categories: Attenuated Poor. Attenuated Intermediate. Attenuated Mild. You can’t tell which category is which until the child is much older (around 2), and they’re showing signs of development. The rate at which they develop – thats what defines which category you’re lumped in.

What this means first and foremost is that at the time of diagnosis (typically a few weeks after birth) it’s impossible to tell severe or attenuated, unless your child has two of the handful of mutations which have previously been expressed to show how much protein they produce. Regardless of this almost every parent is told their child is severe. If a doctor see’s your child as sleepy and lethargic (even if it’s just a bad day, or post seizure) they’ll lean towards severe. Severe is where we’re primed to be, and severe is what we fear in that newly diagnosed haze. Severe is the safe worst case scenario.

Thing is, it isn’t until our babes start developing that the severity of NKH comes to light.

There’s a slide in a talk done by one the NKH researchers that spits it out:

Attenuated Mild: Developmental Quotient 50-80
Attenuated Intermediate: Developmental Quotient 20-50
Attenuated Poor: Developmental Quotient <20

The Developmental Quotient is a score – it’s the developmental age divided by the chronological age. As the parent of a developmentally delayed child – that’s a scary score. In my ignorance, I know Mikaere’s delayed, but I don’t know *how* delayed. Very seems nice ambiguous score. I know he’s not even close to his peers, and he’s been passed by babies a year and a half younger than him, but there’s nothing concrete to latch on to.

And that was fine until in Boston I spoke to researcher, showed him a few videos of Mikaere and after a pause, he said Mikaere was unlikely to be severe, he was showing milestones that perhaps put him in the attenuated poor category. This same researcher had seen Mikaere a year before and had said without a doubt he was severe at his current presentation.

Attenuated Poor. That shocked me. What would attenuated poor mean for us? Would it mean more time with Mikaere? What would our future look like? Will I (dare I even hope) need to be looking at support and facilities and special needs schools? (Will we make that it that long?) – what kind of support will we need? Will we make it to the world of special needs vans and hoists and support with a teenage Mikaere (Can you even IMAGINE?!) Attenuated Poor threw me off my severe, live in the short term kind of mentality. What would attenuated poor mean for us as a family?

How do we make quality of life decisions for our family with such uncertainty in our future? You can see the kind of emotional mess my brain went to with the words ‘attenuated poor’.

But I’m also kind of a logical person, so my first port of call was can we confirm that Mikaere is, or isn’t right now, on the attenuated poor scale? Which is where that Developmental Quotient came in. It would tell me. There is a standardised test and a score and NUMBERS. I never wanted to know how delayed Mikaere was before and now it was all I could do to not do the test myself.

In the studies that discuss NKH Severity, there are three scales of development that could be used: the Bayley Scales of Infant Development, Mullen Scales of Early Learning, or Wechsler Scale of Intelligence. The Bayley Scales is the typical standardised measurement in the UK, and our physio was trained in assessment. So off we went. She came and Mikaere was assessed.

It’s heartbreaking to look at the long list of milestones by age and know your baby can’t do the majority of them. What a knock. Still, I cheered for everything Mikaere could do. We marked off some milestones, which is positive (he’s on the scale, you know?) and just – we got through. I had to remind myself that MIkaere hadn’t changed. Mikaere was still his happy little self and he couldn’t do anymore or any less than he was yesterday. He’s still just fine on his own little path.

Deep breath in. Slow breath out.

We got through the assessment and I put it out of my mind until the assessment report came.

Cognitive: Age equivalent: 3 months.
Language Receptive: Age equivalent: 3 months 10 days.
Language Expressive: Age equivalent: 6 months.
Motor Fine: Age equivalent: 2 months
Motor Gross: Age equivalent: <16 days

Mikaere was 21 months when we did the assessment with an average development of about 3 months. Oh my heart.

DQ Final Score: 3/21= 0.14 or 14%

But there we go. The numbers are pretty clear. Mikaere’s solidly in the Attenuated Poor Category.

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