The new link I posted, under EDS sites (New Article...) has some really great information about a study done by Milhorat, Bolognese, Nishikawa, and Francomano. It explains that people with EDS and chiari have distinct changes in the position of brain structures upon upright posture. These changes result in lower brainstem compression and symptoms. This helps to explain why I need to lie down so much of the time.
In addition there are several new links under TCS sites that report on the outcome of tethered cord surgery for treatment of chiari. It's good to know that this information is being reported, and coming from multiple places. For example, a doctor in Barcelona has been successfully performing surgery on occult tethered cord.
Just in case you're interested in the newest information.