This article leaves out some of the detail from older articles (specifically [1]) about this patient where they describe the painstaking process by which they determined these patients were answering yes-or-no questions knowledgeably. See also [2] for an older article with more detail around the process.

[1] http://www.nbcnews.com/health/health-news/brain-scans-reveal...

[2] http://www.nytimes.com/2010/02/04/health/04brain.html?em