Neurodevelopmental Disorders and Spectrum Bias

Pettersson E, Anckarsäter H, Gillberg C, & Lichtenstein P (2013). Different neurodevelopmental symptoms have a common genetic etiology. Journal of child psychology and psychiatry, and allied disciplines, 54 (12), 1356-65 PMID: 24127638


Christopher Gillberg: "When children display problems in one area, it might be more important to, as early as possible, set up a strategy for helping with all related symptoms rather than trying to help only with a specific diagnosis (which often will change over time)." Dorothy Bishop: “We may feel comfortable with our domain-specific labels for neurodevelopmental disorders, but they do not capture the clinical reality.”

Did we end up going down this path because of spectrum bias? Most children that are seen in clinics are seen by a single focus practitioner. Even when they are seen by a team for diagnostic purposes, they are still treated individually by practitioners such as OT, PT and educational psychologists. In addition only those with the highest level of behavioural problems get past the GPs who act as gatekeepers. This has been thought to be the reason why more boys than girls are diagnosed with neurodevelopmental disorders; the boys display more extreme behaviours thereby getting more attention.

As much research goes on in secondary centres, that is within the hospital or with the community consultant, rather than in primary care, those that haven't made it past the GP gatekeepers will not end up being part of the research cohort. This means that the wider population of those with neurodevelopmental disorders will not have been studied, leading to a spectrum bias when formulating the diagnostic criteria and tests.

Additionally, because of spectrum bias, children will have been filtered into specific subgroups resulting in confirmation of domain-specific labels. One of the 'gold standards' for research in autism has been not the diagnosis of autism but whether or not the researchers have administered DISCO, ADOS or similar diagnostic criteria. This immediately excludes any children who do not present with the main core characteristics of autism as observed by the specific diagnostic test. Additionally it has been shown that children who receive a positive diagnosis under one of these tests at a young age, can often fail to meet the threshold at an older age, then again with the passing of time, perhaps to adolescence or young adulthood, with a different diagnosed test, will regain the specific diagnoses. This will result in not just very specific subgroups, but will concentrate the focus of any intervention or further observation into one small black and white clearly defined area.

The experience of families is very different. They 'study' a single subject, N=1. They see the whole child, rather than the subset of clinical features seen by each of the child's practitioners. They come to support groups confused by the long list of individual diagnoses the child has collected over the years, asking just what it is about their child that is making it difficult for them to access education or social situations. Often referral to practitioners is done serially, that is one after the other, not at the same time. There can be practical reasons for this, such as the increased anxiety caused by multiple appointments, as well as logistic concerns, especially if the different practitioners are spread over a wide geographical area. However, it also means that only one aspect of the child is dealt with at once, whereas in reality all aspects of a child's development will be interacting together. For instance speech and language therapy will be affected by visual disturbances, physiotherapy will be affected by receptive speech problems, social skills training will be affected by nociceptive hypersensitivity.

All of these situations will be well known by parents and carers, but because of the way that researchers and practitioners have been approaching neurodevelopmental disorders, the wider picture has not always been appreciated in the clinical setting.

Christopher Gillberg's paper is a welcome change to the way we look at neurodevelopmental disorders, but will that change filter down into the clinical settings that so may parents find counterproductive? Only time will tell.

The paper (behind the pay wall) can be found here
Dorothy Bishop's review can be found here

Should Consultant Appointments be Treated Like Business Meetings?

We recently had an appointment with an consultant orthopaedic surgeon to discuss my son's longstanding (not sure if that pun is intended or not!) foot pain. At least that is what I thought it was for.


He did indeed take a comprehensive series of x-rays, the first Ram has had in his life (he is now 17) which showed no structural abnormality.


The consultant was good in that he showed us the x-rays, explained where all the bones were and said that as there was nothing there that could be causing pain, it is likely that his pain is caused by fat pad atrophy. That bit makes sense, because Ram has so much pain in his feet when he puts pressure on them, it makes sense that the fat pads on his feet are no longer right.


But that was not quite how it came out in the consultant's letter. You have to bare in mind that this letter is sent to our GP who originally referred us, not to us. I have no idea if the consultant even realises that I get a copy of all correspondence. So it is important that the letter reflect what happened in the appointment.


First off the actual wording of the letter is “Diagnosis: Pain in both feet, probably due to fat pad atrophy secondary to long standing disuse.” Then he goes on to say, “The history is somewhat unusual in that his parents report that from a very young age (around the age of 3) he appeared to not like walking and therefore took to putting him in a buggy out of doors.” Nope. We didn't even own a buggy! Living in the countryside with no pavements there wasn't much use for one. Once Ram grew out of the backpack he had no choice but to walk everywhere. We didn't start using a buggy until he was 8, and even then Ram was very active swimming, climbing, trampolining and tricycling after that. It was only when he hit puberty that the fatigue set in and he slowly lost all his fitness.


But secondly, and perhaps more bizarrely, he said, “He is currently understood by his parents to be on the autistic spectrum disorder. In clinic today I found him to be articulate and did not obviously fall on the autistic spectrum disorder although I will admit that I am not expert in such matters.”


Hmmmm...we were not seeking an opinion on whether or not our son is on the Autistic Spectrum and if we were, we wouldn't have gone to an orthopaedic surgeon! By his own admission he is not an expert, so why even mention it when it wasn't on the agenda.


Oh. Agenda? But there wasn't one! At least not a written one. I suspect there is possibly a hidden one, perhaps our GP made some comment in his referral letter that lead the consultant to think that the parents have made up all this stuff about their son. Or maybe the GP just mentioned it as a way of warning the consultant that this young man will show up wearing a strange hat and have a stim that involves spinning the cord of his hoodie.


And the report? Serious inaccuracies which have already be distributed to the GP and physiotherapist. How does this leave us as parents feeling? We feel that we have not been listened to, that the judgements were made before we even got to the appointment or at the very least within the first few minutes, and that we are not partners in our son's health matters.


So how can this be avoided? I got to thinking about various business meetings that I have been involved with. There seems to be two types, those that have someone taking the minutes; they are typed up, distributed for comment, then officially agreed at or before the next meeting. The other type is where the minutes are prepared as the meeting happens, being agreed on the spot.


If I had produced minutes that were that wrong, or if I was charing a meeting that strayed from the agenda, I wouldn't last as a chair for very long. So why should consultants get away with it?


Maybe it is time for appointments with consultants to become more like business meetings where there is an agenda, where people's contributions are valued, where minutes are agreed before they are distributed, and where people feel listened to.


As for our situation just now, our consultant will have a two page letter hitting his desk next week copied in to our GP and physio, telling him just what he got wrong in his letter, explaining a little more about ASD, and containing some of the history that he didn't bother to take in the appointment. Maybe next time he will be more careful and treat the parents of his patients more like business partners and less like bystanders.