DISCLAIMER: I would like to emphasize for those people who stumble upon this blog that I'm not a doctor, and I have no medical experience other than the approximately 900 doctor's appointments I've been to in the past two years. I just know about these things in relation to how they apply to Connor and not anyone else's child, so if you want accurate info on this sort of thing, please please please ask your doctor or go to the medical library instead of looking it up on the Internet. The library is your friend.
Today's topic is the pons.
The pons is part of the brainstem-- it's found at the base of the brain between the midbrain and the medulla. I'll draw you a cute little picture here so you can see where I'm talking about. The pons is a pretty important part of your brain, and it has quite a few different functions. Scientists aren't sure exactly what all of them are, as for the most part the brain is a big mystery, but they're pretty sure about a few functions. Here are some of the things the pons does:
-Acts as the communicator of sensory information between the medulla oblangata, the cerebellum, and the cerebrum. Basically it acts as a conduit for all of this information.
-Helps regulate breathing.
-May possibly have some effect on REM sleep and dreaming.
-Contains the reception points of four cranial nerves:
-- The Trigeminal nerve, which controls the sense of touch and pain in the face and scalp
and also has a role in biting, chewing, and swallowing
-- The Abducens nerve, which controls the movement of the eye outward
-- The Facial nerve, which controls facial expressions and the movement of one of the
bones in the inner ear
-- The Vestibulocochlear nerve, which transmits sound and balance information from the
inner ear to the brain
So Connor's pons is hypoplastic, which is a fancy-shmancy word for too small. All of the parts are there, but they are all undersized. Another way of writing this condition is pontine hypoplasia. A small pons can have a variety of different effects on different people depending on how small the pons is and which parts are too small. It's also sometimes difficult to tell with Connor which issues are due to the pons and which are due to one of the other neurological issues he has, but the pons is probably affecting him at least partially in several areas.
First of all, he has difficulty controlling his muscle movements and gets very frustrated when his body won't do what he tells it to do. This could be because the information isn't all being relayed due to the smaller connection between the cerebrum and the cerebellum-- only bits and pieces are getting through, or they're getting through at a delayed rate. He also has an extremely high tolerance for pain and a fairly severe sensory processing disorder, which could be caused, as in the motor skill issues, by information not making its way properly through the pons. His breathing is fine, thank goodness, except when he's having a seizure, which is a whole other story that I'll talk about on some other Medical Monday. He seems to sleep pretty well, too, and we're pretty sure he can dream as he makes little noises and facial expressions in his sleep. Where the small pons seems to have had the biggest effect for him is in the nerves that it acts as a receptor for.
The most obvious issue is with the Abducens nerve. One of Connor's eye conditions, Duane's syndrome, is caused by this nerve not working the way it should. As for the other nerves, well, he's able to swallow, but he has difficulty coordinating his jaw movements, drools due to weakened jaw muscles, and does not chew at all. He has what the doctor calls "reduced" facial expressions. Part of the issue is that his upper lip is still connected to the underside of his gum, but he also seems to have some weakness in his facial muscles. Connor has extremely poor balance, and the doctors suspect he might have some difficulty processing the information coming into brain from his ears, as he sometimes seems much more alert and able to locate sounds and other times seems to completely ignore them. All of these things could be caused by a hypoplastic pons.
We're very lucky that his breathing was NOT one of the things affected, or it's likely that he wouldn't have survived past birth. As for a prognosis or cure, well, none of these things are treatable or "fixable" because they are due to his brain structure, but we can help him form new brain pathways that can help with some of the issues, such as the sensory processing disorder and motor skills. We can due this by continuing to expose him to new situations and to help him practice moving his muscles over and over. We've already seen big improvements in those areas, and hopefully he'll continue to get better as time goes by!
There's not a whole lot out there in regards to the effects of a hypoplastic pons, but here's some information about its general function:
Just One More Day: Function of The Pons-- this website deals with tumors of the pons, but has some valuable information. Many of the symptoms of a pons tumor have similar effects as having a small pons because the symptoms are all caused by impaired function of the pontine region.