Closed head injuries are my VERY favorite patient population, but they can be VERY challenging! Every person's injury is different, and their deficits different, because varying the injury location by even the tiniest bit has different results. You may see physical deficits, cognitive deficits, or any combination of the two. Some people suffer only a mild headache, or maybe some slight forgetfulness,and some people end up unresponsive, on a vent.
Many tend to be impulsive, and rather concrete in their thinking, which makes safety a big issue. I have had some that were ambulatory and physically very strong, but violent. Some are prone to rage. It may be unprofessional to say so, but many have such unusual perceptions of their environment, that I just have to giggle. For example, one woman was convinced for about two months that she was pregnant with ducks!
Head injuries take a long time to rehab: the quicker the progress, the better the prognosis, but they may continue to make slow progress for as much as two years. Many of the cognitive deficits can be overcome by behavior modification and cognitive retraining.
Rehab is hard work, physically and emotionally, but there are great rewards in knowing (at least most) of your patients will get better than they were when you first started caring for them. Rehab nurses are very "hands on", so the staffing is usually better than med/surg units. Rehab is usually a relatively long process, so you get to know your patients (and their families) very well.
If you have a chance to work on a rehab unit with this population, I would definitely recommend it!