Brain injuries come in all forms and levels of severity, and few are inexpensive to manage. Treatment for a severe brain injury can cost $2 million to $4 million. But according to a neurological surgery professor at the University of California, San Diego, most Americans lack access to the level of care and services they need.

After U.S. Rep. Gabrielle Giffords was critically injured in a mass shooting, she received some of the best brain-injury care the country has to offer. Since then, she has lobbied hard for the rights of all Americans to receive the same level of care, from the initial intensive trauma care to the ongoing therapy she continues to receive. But how far are we from that ideal?

One element of brain-injury care is the research of injuries and the best way to treat them. Although much more work remains to be done in this field, Giffords' experience demonstrates what strides have been made in brain-injury research. But if you're an average citizen who suffers brain damage in a car accident, for example, don't expect the level of care you receive to reach the ceiling of what scientists have discovered. More likely, your treatment will depend on your state, insurance plan, hospital and your advocates -- be they family members, an attorney or anyone else with your best interests in mind.

Some states have laws mandating rehabilitation for people with brain injuries. Others have mandatory insurance policies covering all medical costs, which can come in handy considering that collisions are one of the leading causes of traumatic brain injuries. Some states even have special trust funds for TBI sufferers.

When it comes to insurance, whether your brain injury is covered depends on your policy. Most cover the intensive care you'll need immediately after you're injured, but much fewer cover long-term rehabilitation that will put you back on the road to a normal life. Likewise, only a handful of hospitals have the necessary trauma and rehabilitation units.

So what can you do if you or a family member suffers a brain injury, especially in an accident caused by someone else? To be an effective advocate, you must speak loudly and often, or find someone who can do that for you. Don't expect to get the best treatment money can buy without shouting for it.

Source: ProPublica, "Giffords May Get Better Brain-Injury Care Than Most of Her Constituents," Lena Groeger, Jan. 17, 2012