Okay, here goes:
How do neuropsych tests "point to areas of the brain where the seizures are originating"?
Generally speaking, if you do well overall, but do poorly on a few tests that measure the same function, the neuropsychologist knows which area of your brain is not working properly. In the context of epilepsy, that area may be where seizures are coming from.
Here are a few of the things the neuropsychiatrist might look for:
1. Patients with left-sided lesions show poorer verbal memory compared to the non-verbal component.
2. Patients with lesions situated on the right-side of the brain do poorer in non-verbal tasks than in verbal tasks.
3. Memory for relational information (pairs of single elements like word-object) relies primarily on the hippocampus. Memory for non-relational information (single words or objects) can be handled by the nearby mesial temporal regions. Mostly these areas work together, but certain tasks are more specific to one region vs. the other. In particular, recollection-based tasks (free recall, autobiographical memory, etc.) are more associated with the hippocampus.
4. The hippocampus also plays a role in "stabilizing" memory for long-term retention. Someone with severe amnesia might forget something after just a few minutes. Someone with TLE might suffer from milder recall issues, forgetting significant information after an hour, or after longer delays.
All these measurements are especially important when evaluating someone for possible brain surgery. For instance, if there are severe memory and language deficiencies in the side of the brain
opposite to the one where the seizures originate, the risks of developing post-operative memory and language impairment are high.)
Are there neuropsych tests that measure us (epileptics, or PC "People with epilepsy") vs. dementia patients?
Neurospych tests can be used to look for signs of dementia, Alzheimer's, ADD, learning disabilities, autism spectrum disorders, etc. If the tests are done prior to diagnosis, the the neuropsychiatrist may modify tests or focus on ones specific to a suspected condition. For instance, the Gilliam Autism Rating Scale & Autism Diagnostic Observation Schedule would be used for autism. For dementia, the doc would be looking closely at episodic memory (delayed recall) and semantic knowledge (acquired facts, ideas, meaning and concepts). In order to distinguish age-related decline vs. Alzheimer's the doc would look for certain attention-related deficits in dual-processing tasks, tasks that require the disengagement and shifting of attention, and working memory tasks. For epilepsy, the tests would not ordinarily be used for diagnostic purposes, but for evaluation for seizure localization, extent of any problems, and gauging any changes in function.
In many circumstances it helps to have a baseline test and then a follow-up test at a later date to gauge the nature and pace of cognitive changes (if any). In my case, I had a neuropsych evaluation done when I started Lamictal, in part because on the previous medication I had started to experience cognitive side effects. If after some time on Lamictal I were to suspect Lamictal-related cognitive side effects (I haven't), I could take a second test that might confirm my suspicions or perhaps put them in the context of expected average age-related declines.
I had a neuropsych test done because I had a concussion.
If epilepsy had not yet been diagnosed at that point, the neuropsychiatrist would have been testing to evaluate the nature and extent of cognitive difficulties post-TBI. There are 7 or 8 standards tests used. In addition to memory, attention/concentration, problem-solving, speed of information processing, etc, the doctor would be looking for signs of personality changes (usually things like moodiness, sensitivity, irritability, and reduced frustration tolerance).
Of course, for all of these tests, there are a limitations related to the training of the evaluator, the reliability of the test, the age of the subject, etc. And the tests are evolving as more brain localization data is obtained, especially from things like fMRI.
Sorry for the novel; Hope this helps!
onder:
