Mark,

Here is a quote from the Natl Inst of Health paper that discusses the various studies on Topamax. You can see why it took me all day to get through it all... And it appears as if there hasn't been enough research w one study showing negative results:

"This evidence that administration of TPM [Topamax] confers protection against neuronal damage and cell death following cerebral injury may have implications for learning and memory following cerebral injury. This has been shown in rat models of cerebral injury, induced through hypoxia, induced seizure, middle cerebral artery lesion (to induce ischemia), and TBI. ...

"The studies used rat models to investigate the effect of TPM administration on learning and memory following cerebral injury. Hoover and colleagues found that while there was a beneficial effect on preservation of motor function, learning performance was impaired in brain-injured rats administered TPM 1 month post-injury [Hoover et al. 2004]. Other studies found that rats given TPM had preservation of some cognitive abilities following brain injury compared with brain-injured rats not administered TPM. Amelioration of deficits in learning and memory however, were inconsistent between doses and tests used for assessment making generalization difficult."