Interestingly, my research started while studying the impact of artificial skull deformation on the base and the sutures. Artificial infant skull deformation was widely practiced by the former indigenous people of Peru and Bolivia but nobody knows exactly why they did it. Whatever the reason, the practice of artificial skull deformation caused the sutures to stay open into adulthood.
In intentional infant artificial skull deformation, physicians or shamen of the day used some type of special pads with fiber bindings to progressively alter the shape of the head. The question is did they do it for aesthetics or for correction of an existing problem? Interestingly, in this regard, doctors are now using what are called cranial orthoses that are similar to bicycle helmets(see picture at top of page) for remodeling and correction of skull deformation in infants. Some orthoses are solid and simply surround the head to mold it. Others have custom openings in the helmet to direct the growth of the brain and skull toward the direction of the opening.
The sutures are supposed to join the membranous bones together. They are separated in human infants to make it somewhat easier for the mother and baby to survive delivery of a relatively large head. The sutures start to knit together soon after the baby is born. The metopic suture which splits the forehead of the fetus into two separate pieces is usually closed at or soon after birth. Within the first two years the soft spots called fontanelles will be gone and the separate membranous bones will be linked by joints that look like stitches that are called sutures. The outer surface of the sutures, however, will stay open well into adulthood due to the effects of upright posture on bio and fluid mechanics in the skull.
The method of artificial skull deformation used in Peru and Bolivia caused the sutures of the skull to remain open from the inside to the outside into adulthood when they should have at least started to close on the inside. To me this suggests an increase in intracranial pressure. Increased intracranial pressure in children is often due to hydrocephalus and that is how I got started looking into hydrocephalus and neurodegenerative diseases.
At first, when looking at the skulls like the one above, I thought the physicians or shamen of the day had unintentionally caused hydrocephalus due to the skull deformation similar to the consequences of extreme craniosynostosis. Then it occured to me perhaps they were trying to treat hydrocephalus. Why else would people go to such extremes?
Similar to skull deformation, hydrocephalus is as old as humans are. It’s my opinion that humans are predisposed to hydrocephalus and skull deformation due to upright posture and the unique design of the skull, spine and circulatory system of the brain. The key sign in hydrocephalus is a rapidly developing oversized head. People, community healers and especially mother’s most likely knew the signs of hydrocephalus long before recorded history. The signs are easy to see.
Closer inbreeding in tight knit mountain and valley communities of Peru and Bolivia could have passed on a genetic skull design flaw such as an undersized cranial vault relative to the size of the brain. As mentioned above, craniosynostosis can cause an increase in intracranial pressure but so can a condition called craniodysostosis such as an undersized base of the skull, especially the posterior fossa.
Rather than hydrocephalus perhaps they were attempting correction of craniosynostosis. But this seems hardly likely since the outcome was far worse if the object was correction and restoration of normal shape and symmetry. On the other hand, if they were attempting correction of hydrocephalus, they were far more successfull at it than their western contemporary physician counterparts before the advent of shunts. The reason why is because judging by their molar teeth they obviously lived to be adults. In western cultures, before shunts, children were often severely mentally impaired and died young as a result of hydrocephalus. That would make the physicians or shaman of the former indiginous people of Peru and Bolivia smarter than we give them credit for doing what they did. Fortunately today, due to shunts, children can, in many cases, live normal lives.
Unfortunately, we can only guess why the former indigenous people of Peru and Bolivia performed intentional skull deformation on so many of their infants. Suffice it to say however, the extreme skull deformation altered the flow of blood and CSF which may have compensated for the hydrocephalus or it opened new pathways.