t97tab,

You have asked a very BIG question. The delay of symptoms from concussion is well known. I will have to do some research to find abstracts. The basic physiology is simple. The brain is mildly damaged by the concussion in a way that does not kill brain cells. Over time, the brain tries to let these cells heal as they continue to provide some function.

After a few days to even a few weeks of letting/waiting for these cells to heal, (six weeks is not unheard of) the damaged cells release a signal in tRNA (transmitting RNA) that shuts down the injured cells. This continues to happen until a clean margin is formed (clean margin means cells that have no damage). The healthy cells know how to ignore the shut down signal.

This is when the symptoms start showing up. In some cases, PCS symptoms are hidden by other causes. A head ache can cause cognitive problems. Insomnia can do the same.

The psychological community also knows that anxiety and depression can cause cognitive symptoms that are similar to concussion. These leads to many psychological professionals to claim anxiety or depression rather than concussion.

The MMPI-II (Minnesota Multiphasic Personality Inventory -2nd edition) has an over-lap. Scales 1,2,3,7 and 8 will elevate for both concussion and depression/anxiety. My own neuro-psych assessment showed this elevation but other tests showed no depression. The evaluating Ph.D. still tried to diagnose depression as the cause.

I would suggest you do some research on www.tbilaw.com Attorney Gordon Johnson addresses these problems.

A normal neurological exam is a very poor indicator of concussion for two reasons. First, the Mini Mental State Exam (MMSE) is rarely done adequately, if at all. Second, it is mainly a test of motor function. The nystagmus test is about the only indicator of concussion. Concussion may only be mildly indicated by a nystagmus test (horizontal gaze, follow the light from right to left). It takes a very precise observation to notice the nystagmus of some concussion subjects.

There is some research that says concussion will be indicated better in a standard neurological exam if the different tests were repeated enough times. The study showed that some subjects become very symptomatic after 6 to 12 repetitions of the individual tests. This is a result of mental fatigue that does not show up without repetition.

The best answer is that very few physician, even neurologists, understand the symptoms of a concussion, especially concussions that did not result in a loss of consciousness or post traumatic amnesia.

Of all the concussions I have had (13), only one caused prolonged symptoms from the start. Only one had mild confusion for a few minutes that cleared up. Then, various symptoms manifested a few days to weeks later. All of the others had delayed onset of symptoms.

The Howard Hughes Medical Institute has sponsored some lectures at University of Maryland and University of Washington School of Medicine has put on mini-medical school lectures that have been broadcast on the Research Channel. University of Wisconsin has also broadcast some mini-medical schools and CME (Continuing Medical Education) courses on their doit web site at http://www.doit.wisc.edu/streaming/researchchannel/

Here are some links for you to peruse:

http://www.ejbjs.org/cgi/content/citation/86/5/1047

http://uwmedicine.washington.edu/Sea...x?k=concussion

http://www.doaj.org/doaj?func=loadTempl&templ=about

http://cpancf.com
/NRE00151.pdf

http://www.givebackorlando.com/hepusef/hepindex.html

http://www.btflearning.org/go/ActivityFrontPage?id=58

This last one has some good information. It is worth the time to watch it, especially the diagnostic segment.

If you look back through my posts, I have probably posted about some of the other research I have found. I have so many links saved about concussion that it is hard to sort through.

Keep fighting for your daughter. As you read up on concussion, you will discover how much most neurologists do not know. Become an expert.

My best to you.