Read Online The Ghost in My Brain by Clark Elliott - Free Book Online Page B

circumstances, I became reluctant and difficult instead. Others in my personal and professional life began to see me as sometimes unaccountably unreliable, or even obstructionist. Frustrated with my own fluctuations, I began to see myself that way as well.
    It was hard to explain why it was possible for me to grade one exam in ten minutes, but it took all day to grade five of them; or why one minute I could converse freely about a complex unification algorithm used in AI programs, but ten minutes later couldn’t understand what “next Tuesday at 4:15” meant.
    Gradually I began to see a pattern. As long as I did not have to
think
and could avoid certain kinds of tasks, and if there were no demands on my balance system, I was more or less functional. The more I used my brain over the course of minutes or hours, the less functional I became. And the rate of my deterioration was highly dependent on the
kind
of brain activity I was performing: Trying to process two streams of simultaneous input (such as talking on the phone while jotting down notes on the conversation), making decisions, or sorting out the visual landscape when shopping, would leave me incapacitated within a few minutes. Performing simpler activities, such as driving, washing dishes, and socializing that did not involve attending to significant conversation, did not cause deterioration. Over time, I learned to make reasonable predictions about my cognitive and sensory breakdowns based on the kinds of thinking activities I had to perform, and on the current state of my brain resources.
    Equally important were the varying rates at which I could
recover
from my distress.
    Understanding the relationship between these two—the ways that breakdowns occurred, and the different speeds with which I recovered from them—is critical to understanding many of the otherwise puzzling episodes that I so often experienced. Nor was my experience unique: other concussives I spoke to over the years had exactly the same perplexing difficulty. Over time I found myself using a
cognitive battery
analogy to capture the structure of this recurring breakdown and recovery phenomenon:
    Imagine that a concussive has three sets of batteries that power her brain.
Set A
—the working set—is immediately available, and also recharges rapidly within a few hours.
SetB
—the first level of backup batteries—can be accessed if Set A is exhausted, but takes longer to recharge, possibly up to several days.
Set C
—the deepest level of backup batteries—can be used as a last resort at times of extreme demand when Set B is exhausted. But caution must be exercised—Set C charges very slowly, over the course of up to two weeks.
    Now here is the problem—it is not possible for our concussive to charge Set B very well until Set C is fully charged, and similarly it is not possible to charge Set A very well until Set B is fully charged. So, once Set C has been drained, it is going to be a long time until our concussive’s brain returns to (relatively) “normal” operation.
    As long as our concussive can get by using her Set A batteries to power her brain, life will be relatively normal. But this means that her brain can only be used for short periods, and not in ways that are very demanding. These short shallow-demand periods must also be interspersed with regular brain rest—and often, in particular,
visual system
rest. The concussive needs periods of doing nothing, without thinking, or dreaming, or taking action.
    But, life intrudes. Some tasks require that our concussive stay focused for longer periods, or require more intense use of her brain than can be powered by the Set A batteries. Going shopping, for example, requires that she perform extensive pattern matching and decision making. Caring for children requires that she always be prepared to respond, even when it is not convenient. At these times the Set A batteries are rapidly used up,