Friday, October 14, 2016

Delayed reaction

Paula and I recently attended a dinner party where everyone either had a spouse with Alzheimer’s or had been diagnosed with the disease itself. All of the diagnosed individuals happened to be men, and all but one of us reported suffering a concussion as a child. Mine came when I was around six, riding on the back fender of my brother’s bike. When I came to, I was lying in the back seat of our car, not long before we reached our doctor’s office, a trip of about fifteen minutes. It is clear that I had fallen backwards. My brother, who was four years older, recalls seeing an egg-shaped lump protruding from the back of my head. He raced down our hill to alert our mom. This was long before kids wore bike helmets.
Could that single childhood concussion have predisposed me to develop Alzheimer’s in middle age? From an early age I liked to play rough games—wrestling with my brother on our carpet, not far from our brick mantel, or playing tackle football in our backyard, without helmets, often with bigger boys. The playgrounds at our elementary school were entirely paved, which ruled out playing tackle football—unless snow was on the ground. In one of the years when we did get substantial snow, I banged heads with a friend of mine. I didn’t exactly feel the pain but I smelled it—an odor of rubbing alcohol, or something else one might encounter in a hospital. In sixth grade, I played my first of seven seasons of organized football.
An article published in 2011, “Long Term Consequences: Effects on Normal Development Profile after Concussion,” notes that “immature neural tissue differs from mature tissue in reponse to injury.” The key word is “plasticity.” A young brain, in other words, is more vulnerable to damage than an adult brain is. In one sense, I feel fortunate. Whatever damage I suffered from that long-ago head injury, it had little effect on me as I was growing up. I generally did well in school, though in math I got no further than geometry, a subject that I struggled with. It’s possible that my childhood bicycle accident did enough harm to damage my spatial reasoning. My sense of direction has never been good, and these days it is atrocious.
But according to the study I cited, many childhood head injuries come with much more damaging consequences. “Because the prefrontal cortex is one of the last brain structures to mature, it is not surprising that parents [often] report attention deficits, hyperactivity or conduct disorder,” following a concussion, according to the study. That my head hit on the back of the skull, rather than a more sensitive part of the brain, may have spared me from worse damage. My consequences, to the extent that I can document them, were a good deal more subtle. I was a high-spirited child, but I did well in school. Yet I do believe that my concussion roughly 50 years ago is at least partly responsible for my short-term memory and executive-function difficulties today. Throw in the countless helmet hits I endured in my seven years of organized football, and there should be little mystery about why I began to experience mild symptoms of Alzheimer’s a few months before my 51st birthday.

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