I had a girl come in with anxiety and attention issues, and her exam was almost boring. Reflexes looked good. She could balance all day. Her eyes were smooth, with only a small deficit when I combined balance and tracking.
Then I checked her vagal system. No gag response. No pupillary constriction to light. The most important finding wasn't either of those. When I activated those systems, her oxygen saturation dropped to 92 within seconds.
That changed the whole case. Her primary wasn't neurological. It was oxygen. Even the tracking deficit made sense: she was running out of energy as her oxygen went down.
Why the Pulse Ox Belongs on Every Exam
Think about the brain's energy sources. If a system isn't getting enough oxygen, you can stimulate it all day and you won't get a response. A weak system needs stimulus, but it also needs the fuel to respond to that stimulus.
That's why I keep a pulse ox on through the exam and therapy, not just at intake. A resting number can look fine. What you're watching for is what happens when you load a system: vagal testing, activity, balance work. That's where the drop shows up.
Oxygen Problem or Blood Flow Problem?
A clinician in one of our coaching calls brought a case that made this even clearer. A student who sat at 98 at rest would drop to 56 during activity, and fast. A drop like that isn't something to rehab around. Send a note to the pediatrician or primary provider asking them to check for anemia and asthma.
Then work through the other possibilities:
Ribs. I always check rib biomechanics first. If I adjust and saturation comes right up, it was rib dysfunction.
Breath holding. Some kids hold their breath during effort. I once had a child who slept under the blankets every night. He'd become less sensitive to CO2 and could push his oxygen remarkably low before he had to breathe. It's worth asking the question directly.
Blood flow. POTS can look like an oxygen issue when it's really a perfusion issue. If the extremities go cold or purple as the number drops, it may not be oxygenation at all. A thermal camera can show you this: hands that turn purple as the number drops point toward blood flow.
Then Ask Why the Lungs Are Inflamed
If anemia and rib mechanics aren't the answer, listen to the lungs. An electronic stethoscope is a simple tool here. Allergy and asthma testing may be needed. Then the question becomes metabolic: what is keeping the lung barrier open? Gut barrier breakdown and zonulin, chronic sinus issues, food sensitivities, food allergies, and environmental allergies can all play into it.
What Actually Moves the Needle
For that girl, oxygen became the first priority. The plan was hyperbaric to bring oxygen levels up, then a low-flow nasal cannula during therapy so we weren't working against a deficit. Only then did we move into lasering the brainstem, midline cerebellum, and vagal areas, and stimulating the vagal system with a StimPod or simple vagal activities. The goal was to get her to where a cotton swab at the back of her throat produces a real gag.
For the clinician's student, the same principle applied. Put the oxygen concentrator on with a cannula while he does activity. Green laser over capillary beds close to the surface, like the nose, palms, feet, carotids, mouth, and head, can help too. Put a pulse ox on a child with low saturation, laser for a while, and you can often watch the number start to climb.
In many of these kids, we commonly see saturation normalize by the middle or end of the first week of intensive work and stay there. When it doesn't, that's your signal to keep digging.
Final Thoughts
A clean neurological exam with an unexplained presentation is not a dead end. Sometimes the primary isn't the cerebellum, basal ganglia, or frontal lobe. Sometimes it's that the brain doesn't have the oxygen to do what you're asking of it. Keep the pulse ox on, load the system, and watch what happens.