Scientists, by nature, are skeptics (35yr history in neurological research), so be careful when digesting this report. Though the findings are not entirely implausible, the study has so many red flags that there's insufficient space to discuss them all. Aside from the low gliding time JMF pointed out, there is no appropriate control group (Sure, they were familiar with video games, but they don't give important metrics). It is a real stretch to think brain volume can change after just a few hours flying spread over months/years?!

Caution: Hypobaric Pressure- Regarding perhaps a more interesting study related to the Perlan 2 project. Our institute was asked to evaluate U-2 pilots following an increase in frequency of decompression sickness. The study found a significant number of white-matter lesions (e.g, stroke-like) in the brain of affected subjects. Some pilots (while in flight) were nearly incapacitated and others suffered long-term neurological changes. Why? The thinking is that these pilots operate at 70,000ft but cabin/suit pressure is maintained at only around 30,000ft!! I've heard mention that the Air Force is/has changing that to 15,000ft pressure alt (2013 cabin altitude reduction effort (CARE)). The Perlan 2 glider is pressurized to 14,000ft, according to their website info.

I'm a firm believer in maintaining brain health; use it or lose it! Physical fitness helps in maintaining cognitive skills at least as much.

Public-distilled summary of findings:
http://www.reuters.com/article/us-he...97M0RT20130823
Original article:
https://www.ncbi.nlm.nih.gov/pmc/art...ihms488856.pdf
Mike