Tympanic temperature reflects intracranial temperature changes in humans
Z. Mariak, M. D. White, T. Lyson and J. Lewko
The purpose of the study was to identify extracranial locations in which temperature changes in humans reflect those of intracranial temperature in a reliable and repeatable way. This was achieved by subjecting 14 non-anaesthetized patients after neurosurgery to face fanning while intracranial and extracranial temperatures were continuously measured. In all patients the cranium was closed and the group included both febrile and non-febrile as well as hyperthermic and normothermic patients. The patients' faces were fanned for 20-30 min, with a small fan at an air speed of 3.25 m sm1. This gave intracranial temperature changes measured in the subdural space (Tsd) that were highly and significantly correlated (r=0.91, P<0.05, n=14) with changes in tympanic temperatures (Tty). A low, statistically insignificant correlation (r=0.40, P>0.05, n=12) was found between Tsd and oesophageal temperatures. In conclusion, intracranial temperature changes, induced by face fanning, were reliably reflected by the changes in Tty.
It has been suggested that heat intolerance is due to the effect of heat on demyelinated neurons. Alternatively, it has been suggested that our heat intolerance is due to actual impairment of the brain's ability to cool itself. It would take a simple study to see if our brains are indeed hotter than the brains of healthy controls. I am surprised if it has never been done.
If pwMS do indeed have hotter brains (or have hotter brains under select circumstances, such as in hot rooms or after exercise), then the next step would be to see if pwMS who have had successful CCSVI procedures experience a normalization of brain temperatures.
If the CCSVI procedure leads to normalization of brain temperature, then this could explain some of the improvements seen post-CCSVI-procedure, because it is known that demyelinization would cause our neurons to be less effective at conducting impuses when at a higher intracranial temperature.
According to this, as low as a 0.2 C rise in central temperature measured tympanically might have an effect on us.
http://archneur.jamanetwork.com/article ... eid=570795