Ictal Onset Zone

After Hannah’s seizures Monday night and Tuesday, our neurologists were able to get more information about where her seizures are originating from.  With the new grids in place, we now have coverage of most of her left frontal lobe, however, the origination point is still not fully covered by the grids.  We still have the same problem in that it appears to be originating in the top-right corner of the grids (when looking at it from her left side). 

This means the ictal onset zone is very large.  It includes the motor strip area, and it is not fully represented by the grid (they still don’t know how far back and up it extends).  The ictal onset also spreads rapidly to most of the area that the grid is covering.  The consensus is that resection will not really be an option due to the proximity and inclusion of the motor strip.  They (and we) do not want to risk paralysis or loss of sensation (touch). 

Obviously very disappointing. 

Cortical Mapping

Before making any final decisions, we are still going to do mapping today.  Mapping is a long process to try and determine what each part of Hannah’s brain does.  She currently has 112 electrodes sitting on the surface of her brain.  The neurologist is going to isolate two electrodes at a time and send a small electrical current between the electrodes.  We will then be watching Hannah for any muscle movement or listening for her to identify any type of “weird” sensation (tingling, movement, inability to talk, etc, etc.).  With each pair of electrodes he starts at 2 milliamps of current and works his way up to 15 until there is a response.  As you can imagine, with 112 electrodes, and all the different current settings, it will be a long process.  Hannah does need to be awake and alert during the process, and she needs to have been seizure free for several hours prior to (and during) the process.

Along with a neurologist (or two), Hannah’s nurse will be in the room, two EEG technicians will be there, and a family life specialist will be there to help her.  It will be a crowded room.

Vagus Nerve Stimulator

If we do not end up doing the resection, our neurologist would like to implant a Vagus nerve stimulator during the same surgery that the grids are removed.  The stimulator is a small device similar to a pacemaker that is implanted to electrically stimulate the vagus nerve.  This procedure was discussed before we decided to attempt surgery, but our neurologist didn’t (still doesn’t) feel it will be very effective in controlling the type of seizures that Hannah experiences.  However, since she will be under general anesthesia anyway, and it is a very minimally invasive procedure to place the stimulator, he feels it is worth trying.