Friday, July 26, 2013

Epilepsy and computers: Types of Memory

Last months my son and I spent a week in hospital again for a regular post-surgery check up. As you might know from past blog posts, my youngest son had a brain tumor which caused epilepsy. The tumor and some brain tissue including the hippocampus on his right side were removed two years ago. A hippocampus is like the central memory controller in a computer and fortunately we have two of them for redundancy and failover.

When you work with computers, especially database systems like DB2 or Oracle, all day, it is interesting to look deeper into how the human memory works. There is a sensory memory acting like an I/O buffer, the short-term memory (think CPU registers, caches, and main memory), and the long-term memory (disk, tape, etc.). What I learned at the recent hospital visit is about the different types of long-term memory. Typically it is classified as declarative memory and procedural memory. You can think of the declarative memory as your "storage of facts" or the data in a database system. The procedural memory is for processes that can be performed like walking, playing piano, riding a bike, etc. In DB2 you could compare it to the package cache where information about how to execute statements is stored.

Having different types of memory and different ways of how new information is acquired and managed leads to the surprising fact that even though someone might have trouble learning new facts (because a hippocampus is missing), that person could be still excellent in learning and reciting piano pieces.

As written earlier: How does someone cope with memory problems caused by epilepsy? Our son has occupational therapy to develop strategies for more efficient use of his working memory and also to train (build up) his capabilities. The Epilepsy Society has this summary on the memory issue and workarounds that can be used like sticky notes (external memory), task lists, etc.