You are clearly arguing by appeal to authority. The staff at The University of Pennsylvania Center for Brain Injury and Repair is not infallible. Sometimes bad science is produced by even renowned institutions. This is what the study says about the MRI scans:

"MRI neuroimaging was obtained in all 21 patients. Most patients had conventional imaging findings, which were within normal limits, at most showing a few small nonspecific T2-bright foci in the white matter (n =9, 43%). There were 3 patients with multiple T2-bright white matter foci, which were more than expected for age, 2 mild in degree, and 1 with moderate changes. The pattern of conventional imaging findings in these cases was nonspecific with regard to the exposure/insult experienced, and the findings could perhaps be attributed to other preexisting disease processes or risk factors."

Translated to English: Only a few minor brain abnormalities were found. Those could all have been the result of prior, more natural causes. The MRI scans themselves aren't available, presumably because of "security" reasons.

Personally, I don't see why the crickets theory would be implausible at all. Listening at their sound for just 20 seconds was enough to give me shivers and ringing ears. I'd easily go insane if I had to hear them every night for several months straight.