Dr. Brian Greenwald medical director of brain injury rehabilitation at Mt. Sinai Medical Center describes how a person can be changed by a brain injury:

"Although we think of ourselves as our car or our house or what dress we like, what we are is our brain – the mush in the head that is the same consistency as Jell-o – It's our thoughts and our emotions and our moods."

Giffords' congressional staff, Dr. Greenwald, and others caution that regaining speech and rejoining Congress are two different issues:

"Add it all together and she's able to express the basics of what she wants or needs... But when it comes to a bigger and more complex thought that requires words, that's where she's had the trouble."

Read the full story and watch related news videos:

http://abcnews.go.com/Health/gabby-giffords-recovery-rosy-experts-reality-check/story?id=13829783