For those of you who follow my Facebook group, you know I have very limited tolerance for unscientific or unfounded thought in this area. One theme that seems to permeate the web pages and some professional circles is the idea that head flattening somehow CAUSES issues like developmental delay, visual or learning issues, TMJ or jaw issues, long term cross bite, ear infections, and other medical/dental problems. I have culled the world literature many times in my academic career and there is absolutely no good evidence to support any of this. in fact, just rational thinking would suggest that these cannot be accurate.
First, head flattening is very common in some very populous areas of the world and has been for centuries. Some of this is due to longstanding infant swaddling and positioning techniques, and the impact on head shape is notable. For example, the average CI in Korea has been recored as high as 0.90, considerably higher that in the West (0.83). Yet, do these populations show lower intellectual aptitude or have a multitude of medical issues related to their head shapes? No! Moreover, when the Back to Sleep Campaign kicked in in 1992, almost 30 years ago, there was an almost exponential rise in the incidence of head flattening but no recorded increase in developmental delay, TMJ or occlusal issues, ear infections, visual or reading problems, or anything BESIDES many more flat heads. Here is an example of such a conversation with a clinician who is convinced otherwise:
"Well if it was just about cosmetics then yes! You are correct. It doesn’t matter. But it’s not just about cosmetics. Do a Pubmed search for research articles on lasting affects of cranial deformation. It’s been linked to learning issues (specifically reading due to difficulty with vision and crossing midline with their eyes). Also, brachycephaly often means the child spends too much time in their back which leads to slower development and often these kids hate tummy time and skip crawling. Which we know for sure leads to lower coordination.
In addition this man probably can’t wear a hat comfortably or a helmet safely! Goggles won’t stay on as the strap just will slide right up the back of his head so if he wants to be a swimmer it may be difficult. Some of these are minor things to you, but to another person it may be a big deal. I’m not saying we should shame those with flat heads. I’m just saying with repositioning a d education this is totally preventable so why not do that! There is a large difference between fear mongering and just educating new parents on the ways to correct and reasons why."
The problem here is that while this individual knows enough to search Pubmed, she has not researched this subject or the articles sufficiently to know the content and the nuance of what they mean. The best example is the association between head flattening and developmental delay or learning issues. She is correct that there are many studies linking plagiocephaly and developmental delay/learning issue, but none of these studies have shown that deformational head flattening CAUSES these delays or learning issues OR that correcting the shape can improve on these problems. We in the field know that there are three primary reasons kids get flat, and all have an effect on independent head mobility early in life- torticollis, developmental delay, and prematurity. Sure, kids with delays are at more risk for getting flat because they are slower to move than those that do not have delays. However, this DOES NOT justify concluding that the flattening causes delay. All researchers in this area agree that head flattening should be considered a potential marker for developmental delay but that the delay is not caused by the flattening. This is a quote from the Seattle Children's group who has studied this association extensively.
"Preschool-aged children with a history of DP continue to receive lower developmental scores than unaffected controls. These findings do not imply that DP causes developmental problems, but DP may nonetheless serve as a marker of developmental risk. We encourage clinicians to screen children with DP for developmental concerns to facilitate early identification and intervention."
Similar conclusion in another of their studies:
"DP seems to be associated with early neurodevelopmental disadvantage, which is most evident in motor functions. After follow-up evaluations of this cohort at 18 and 36 months, we will assess the stability of this finding. These data do not necessarily imply that DP causes neurodevelopmental delay; they indicate only that DP is a marker of elevated risk for delays. Pediatricians should monitor closely the development of infants with this condition."
In terms of TMJ or occlusion issues, the literature shows that such an association is not supported by the science. A total of 6 results on Pubmed, none of which was relevant.
Visual issues in deformational plagiocephaly also have little literature to support an association. There is one study, which has never been duplicated and has been contradicted by at least one other study, that showed an association between plagiocephaly and visual field defects, but the visual issues did not correlate with side or severity! Moreover, I actually reviewed this study and rejected it because many of the subjects did not have enough head asymmetry to even qualify for a diagnosis of plagiocephaly!
Ear infections were reported in this one survey study by my good friend Lisa David and her group at Wake Med. Unfortunately, this was a survey study that did show a higher incidence of otitis media in plagiocephaly, but this study suffers from some pretty bad methodological issues and was never duplicated. The primary issue here is that there was only a 54% response rate and there was no attempt to screen for the kids for other medical conditions that could confound the data (i.e, have a higher rate of ear infections regardless of the head flattening).
In terms of the aesthetic implications and the concept that people with either asymmetrical or symmetrical head flattening leads to problems with eye wear, fitting of helmets or hats, or any other functional problems, there is NO data whatsoever to support this contention.
So when you REALLY look at the details of the studies, there is really no support that head flattening CAUSES any medical, developmental, or other functional problems.
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