Cycling, macintosh, natural history and life in Singapore - Archives
Tue 15 Jun 2004
About concussions and memory loss
Category : cycling
This was adapted form a post to my cycling list, after one of our friends suffered a concussion. She fell down a steep slope and was thrown off her bike, landing on her face. She was immobile but eventually regained consciousness, was taken to SGH, observed and released with a one week MC.
Now she suffered a mild concussion and lost consciousness. Although it is not an exact science, with some 28 measures out there, the Cantu scale is often used, probably due to its realistic simplicity. And it indicates my friend suffered a Grade II concussion.
Grade II concussions are not common even amongst collegial and high school American football players - a study of 17, 549 players revealed 88.9% suffered Grade 1 concussion and only 10.6% suffered Grade II concussion. Serious impact she took! If you perch on a bike at the top of the slope you will understand.
She experienced the "usual symptoms" - disorientation, confusion, loss of consciousness, partial loss of memory about events prior to (retrograde amnesia) and events after the impact (post-traumatic amnesia).
Maximal post-traumatic amnesia immediately after the injury is not unusual - hence, it was good that she as surrounded by friends who did answer her repeated questions about her whereabouts.
Though her memory may recover with time, a complete recovery often does not occur. There are apologetic psychiatric explanations about this but a mild head injury, though prominent for its transient functional loss, may be in all likelihood, accompanied by pathological damage - in one instance I read about microscopic shearing of nerve fibers in the brain. Ouch!
The treatment for concussion is rest - *Oh! Gasp! Really?* - tell that to my adventurous and active friend. 10 days to two weeks is a recommended rest period. Not that it means she get to mount her bike and tackle BT immediately after that.
Some sports medicine researchers suggest a hasty return to sport may result in "second impact syndrome," which can be erm, really serious? I haven't read enough but it appears to be linked to symptomatic patients (e.g. still suffering from headaches) returning to the fray, undetected or because an athlete's conscious choice.
Though supposedly uncommon and even disputed, it still makes for fascinating reading - there is some evidence that a period of change in brain function (e.g. in metabolic uptake of glucose) lasts between 24 hours to 10 days to allow for healing. During this period the patient may be vulnerable to injury.*So rest!* Somewhere else, I learnt that old fogies like me (>18 years old) are apparently less vulnerable since we don't have developing brains. Wait a minute!?
Anyway, the threshold for subsequent trauma may also be lowered, meaning any subsequent concussion may result in symptoms consistent with a more severe injury.
I've taken two hits myself in the past, mild ones. Grade I if you must, with no loss of consciousness.
In the first instance, I was in Secondary 4, and it was a PE lesson - we were playing rugby. I suffered a blow somehow but continued playing, and only experienced symptoms significantly, after the game was over. Walking back to class, I panicked at the thought of the 'O' levels the following week! I hadn't studied as yet! A classmate looked at me strangely and said it was still early in the year.
Then I could not find my schoolbag - it had been hidden earlier in the science block. I had a game going to evade prefects on guard in the mornings. I would slip past them into my classroom, after morning assembly but before classes began. It was test of how well we knew the school's nooks and crannies. Ironically, first thing I did was to mark attendance of the class since I was class monitor. It became too easy so I abandoned the game.
Luckily my buddy, the class chairman, knew about this duel and brought me to where my bag was hidden. So I got to change and study.
Second time, also during a rugby game, but this time in university grounds. Rather embarrassedly, I collided head first with the other prop - I was trying out playing with the forwards and was enjoying the heightened tacking immensely - up to that point. The little runt (opposition scrum half) we were after slipped out of our hands but even he as taken aback at the two of us groaning on the ground.
Interestingly I was brought back 5 years in time to the hazy events of the first concussion. Right there in the university field, my mind was flooded with the images of schoolboys and our rugby match that day, some six years ago. I silently struggled to overcome the same feeling of disorientation I felt then and now.
This was no namby-pamby déjà vu. This was time portal grade. Presumably the memory fragments associated with a hard blow to the head had surfaced with the right stimulant.
As I struggled to bring myself back to the present time, I pondered about playing in the last game of that day-long inter-faculty tournament. In the end I decided to go ahead and strangely enough, and to my relief, I appeared to regain clarity as I played! Now I find how silly that was.
In both cases, the other players were unaware of my mild trauma. Apparently in the US, they are thus concerned about "bell ringers" who continue playing, unknowingly at the risk of long-term risks. If coaches and other staff are able to recognise mild symptoms (presuming they want to) the athlete's may be spared critical injury.
For some reason, players who suffer a concussion are three times more likely to do so again! Just makes you wonder, doesn't it?
For me at least, its probably good to know the memories of the playing fields of my old school are just a hard knock on the head away.
Guskiewicz, KM. NL Weaver, DA Padua, WE Jr Garrett, 2000. Epidemiology of Concussion in Collegiate and High School Football Players. American Journal of Sports Medicine, 28: 643-650. His literature cited leads you to a large numbers of papers in this field.