1. The Life Cycle of a Concussion the life cycle of a concussion It starts with a big bang. It comes from the sky: a meteor, a falling object, a box. It comes out of nowhere, a car, a baseball, an opponent''s fist, a partner''s fist, an officer''s baton, a player''s helmet, the banned Kani-basami throw during the girls'' judo tournament, a skateboard crash, a roller coaster, the blast of an IED, a low-sitting shelf, a low-hanging branch, a rogue wave, a 2x4. Or you fall off your bike on a quiet road. You do not pass out. You aren''t likely to, less than 10 percent of concussions result in loss of consciousness (this happens only if the rotational forces at the junction of the midbrain and thalamus result in a disruption of the system that regulates your sleep-waking--that is, you get hit at just the right spot). Later, you will wish you had passed out for just a minute or two, as proof to you and everybody else that something happened.

You will secretly wish that there was blood, not too much blood, not like a whole brain bleed. Just, like, a touch of Halloween-style makeup. Your brain, which is the texture of butter, ricochets around in its own liquids. It slams against the wall of the skull. The axons that connect the white matter of the brain--each a tiny filament less than 1/100th of a human hair in diameter--fray and tear. The headaches, the dizziness, these will come soon enough. Right now, you are freaked because something is up with your eyes. You were told by the cartoons that you''d see stars, but actually the world is retreating, as if the air is taffy being pulled and stretched, the world in present tense and you several seconds behind.

Your friend answers the phone call you don''t remember making, scrapes you off the pavement, stealing glances at you in the passenger seat because he''s nervous you''ll fall asleep, or worse. You try to be the same person you were before you fell off your bike, crack a joke about how hard your head must be, only you''re not sure if you actually spoke out loud or if you said the joke twice or if your friend was actually the one who made the joke. This is called, you are told, confusion. At the hospital, if you''re lucky, you''re put through a CT scan. The CT scan does not show a thing, because technology cannot yet detect the microscopic axonal injury of concussion. The scans come back normal. The formal diagnosis is "traumatically induced transient disturbance of brain function," but the people who treat you now and in the coming months interchangeably use the words "concussion," "mild head trauma," and "traumatic brain injury" so that when you leave with the paper that says what you have and what you should do--which you cannot read, why can''t you read? You were in the Acorn group in second grade, which means you have been praised for your reading abilities since age seven and are pretty sure you''ve only gotten better since then--you are lost. You realize you have no idea what a concussion is, really.

Your knowledge about TBI--traumatic brain injury--comes from the movies or the news. The one about the skiing accident, the horrific car pileup, the boxer''s career-ending match, the brilliant lawyer-doctor-professor-soldier-architect who can no longer feed himself and must learn how to walk again with the help of the doting wife. To you, "traumatic" suggests debilitating disability. The images scrolling through your mind are categorized as "severe TBI," an injury that ranks 3 to 8 on the Glasgow Coma Scale (GCS) and likely results in amnesia, slurred speech paralysis, or days of unconsciousness. Think of Tracy Morgan, comatose for two weeks after a speeding Walmart truck crushed his limousine, followed by five months in a wheelchair. Conversely, if you had a moderate TBI, you would have likely passed out for twenty minutes to six hours, and upon waking might face permanent cognitive limitation or emotional lability--9 to 13 on the Glasgow Coma Scale. Think of Roseanne Barr, who talks about how her family took in Holocaust refugees; how, after she was hit by a car at age sixteen and impaled by a hood ornament, she was never the same. "It''s still you," Barr says, "but it''s an artificial intelligence you.

" You are not Tracy Morgan or Roseanne Barr. Apparently, what you have is far less tragic, is in fact minor, which is why they put a little "m" in front of it and call it "mild TBI." Tiny baby teeny-weeny mTBI, a.k.a. concussion, a.k.a.

not something that the Glasgow Coma Scale is very much help with since it only evaluates loss of consciousness. You think of these three categories of brain injury as three separate boxes-- severe, moderate, mild --when in reality they are more like steps down to the same dark, haunted basement. The doctor who treats you likens what you''ve got to "a bad hangover," prescribes Tylenol. You return to work, because the pamphlet says you should be good in two or three days. Here come the headaches, the sensation that your head is full of gauze, distortions in your periphery. You catch the start of people''s sentences, but by the time they get to the question you''re supposed to answer, or the thing you''re supposed to remember the next time you see your colleague or boss, you forget what''s been said. You still can''t read--the words on the page refuse each other like oil and water. So you fake it.

When you do finally get reading back, you can''t recall what the paragraph is about when you get to the bottom. You can''t draw a clock. The numbers get all bunched up, 7 to 12 are crammed together like the condiments on a fridge shelf--and that is definitely not where 6 goes. Even your little nephew knows the 6. You walk outside on your lunch break, and the sun brings new hurt. The whooshing cars, screaming birds, the trash truck, snippets of chatter, lawnmower--it''s all a grind in your head. You have to cross the street because the guy in front of you is wearing a neon-patterned shirt. Your mother calls, you can''t listen to her for two minutes before nausea sets in.

You always thought migraines were an exaggeration, maybe even a romantic notion, and now you know that you were simply stupid and condescending in your illusion of your perfect, contiguous health. You give your supervisor a letter from your doctor indicating that the fluorescent bulbs are an impediment to doing your job; she looks at you askance. If you were a Black woman, that supervisor''s look would be outright suspicious, and maybe you couldn''t even get the doctor to give you a note. You don''t know how to tell your bosses that scrolling causes glitches in your brain, that the overhead lights make you wilt, that a gif brings on a wave of motion sickness. You are tempted to tell the leadership about the woman with migraines from Vineland, New Jersey, who is suing the Cumberland County Board of Social Services for not moving her desk to a window and for then firing her when she couldn''t work. But you can''t afford to lose this paycheck. So you take secret breaks in the supply closet, lying on the floor with damp office-kitchen paper towels draped over your eyes, then go home and wrap a blue scarf around your head. The tinnitus is always there in the background, a remix of buzz saw and elevator music.

You''re sure this noise in your head is what is responsible for the invention of the car alarm, the fire alarm, the alarm clock. You''ve never had triggers before, but these will stick with you: light, noise, movement, plus new vulnerabilities that evolve. Maybe you are one of the lucky ones, met with unconditional love and people who continue to come around (even if they think you''re exaggerating a little bit, which you let slide because you also think they''re exaggerating when they call out sick). Or maybe you understand Virginia Woolf, who, writing from her own sickbed, tells you friends change during illness, "some putting on a strange beauty, others deformed to the squatness of toads." You miss all the jokes, all the fun, and suddenly you realize that your friends have moved on, made new friends who can go out at night or sit in the sun and drink tequila. The last time you went to the beach, the sun made swallowing a problem, and you had to play it down in front of others, even as you were panicking and thinking to yourself, Lord please don''t let me die choking on a ham sandwich like Mama Cass. You are as guilty as your friends: you don''t want to be around you, either. Case in point, the last six months you''ve had "Mambo Number Five" stuck in your head for days at a time.

You have the constant feeling of needing to go away--to be gone. By now, you realize the pamphlet left out that a concussion means mood swings, disequilibrium, disorientation, disinhibition, distance between you and others, vacant staring. No brain is the same, thus no brain injury is the same. You will understand that a TBI, even a tiny baby mild one, a concussion, is true to its Latin derivation and "shakes violently." Your dreams are full of blood. Sometimes you wake up in the middle of the night, not remembering your name. You sit up, heart pounding, sheets smelling of rotting apples, and wonder who this person is in your place. The concussion might have started off as particles finer than human hair, but now it is a giant donut-shaped disk of gas and dust.

When gravity and other forces cause material within to collide, it becomes a full planet. You are your own planet, and that concussed person over there is their own planet, and that one over there is their own planet. You are all part of the same ever-expanding universe, yet you are always apart. Improbably, you get hurt again. You are in a store, in the infant section. A car seat falls off a high shelf and because your back is turned, you don''t see it coming. Sp.