Why do some people find it hard to remember things when they have a head injury?
Short term memory is good for just a few minutes. Someone gives you a seven-digit telephone number to call, you put that in short term memory. Most of us will have forgotten it an hour later.
Long term memory is something you remember for a year, five years, ten years, or a lifetime. If short-term memory items are practiced enough times, it moves into long term memory. That’s the reason most people know their Social Security number “by heart”. They have been required to write it down or “practice it” quite often.
Most people with any head injury have a problem with their short-term memory. Their long-term memory tends to be pretty good. They will say to their doctor “I can remember something that happened in great detail 10 years ago, but I can’t recall something from 10 minutes ago”.
It is common for brain-injured people to forget events right before, during, and right after the injury. This temporary loss is caused by the swelling of the brain. The brain is pressed against the skull. Memory usually returns when the swelling goes down.
Why is short-term memory affected? It has to do with how the brain processes information. Info from our senses goes through a filtering process, sort of like how mail is sorted at the post office.
When the brain is injured, the areas that do the processing get pressed or squeezed due to swelling. A large amount of information and sensory data is coming into the brain and it is not getting processed. The info is not sent to the right places. The mail room of the brain can’t do its job.
The brain can have another type of memory problem. Once data is stored in the brain, it must be able to retrieve it. You meet someone on the street. You know who they are but can’t quite come up with their name. A few minutes or hours later, you recall the name. The brain has been searching and trying to retrieve that bit of information. We’ve all had this type of problem, only in the brain-injured person it is much worst.
Most brain injuries are caused by car accidents, motorcycle and bicycle accidents and falls around the house. Head injuries to our soldiers in Iraq and Afghanistan from those IED’s (improvised explosive device).
Also, there is now a lot of concern about brain damage in head to head collisions in football causing concussions, confusion, drowsiness, nausea, disorientation, lack of coordination, and slurred speech. The NFL is rightly concerned.