The effects of adjunctive topiramate on cognitive function in patients with epilepsy.
OBJECTIVE
We investigated possible cognitive effects of topiramate (TPM) in polypharmacy on patients with intractable epilepsy.


METHODS
Study 1 evaluated 22 consecutively admitted patients whose antiepileptic drugs (AEDs) on admission to the Montreal Neurological Hospital included TPM. Performance on neuropsychological tests administered on and subsequently off TPM was analyzed. Four patients also were tested before taking TPM, allowing comparisons off, then on, and then off the drug again. Measures included intellectual function, verbal and nonverbal memory, language, word and design fluency, somatosensory sensitivity, and motor skills. In Study 2, 16 patients at the Minnesota Epilepsy Group were tested first off, then on TPM with nine cognitive tasks that measured concentration, verbal fluency, language, and psychomotor speed.


RESULTS
In Study 1, significant (p < or = 0.01) improvements were observed off TPM on 13 measures including verbal and nonverbal fluency and certain verbal and perceptual tasks. Notably, verbal learning and memory were unaffected; a limited effect was observed on nonverbal memory. Patients tested 3 times scored better in both tests off TPM compared with on this drug. In Study 2, declines on TPM were observed on all measures, significantly (p < or = 0.05) for tests of fluency, sustained concentration, and visual motor processing speed.


CONCLUSIONS
TPM was associated with declines in fluency, attention/concentration, processing speed, language skills, and perception; working memory but not retention was affected. As the two studies used an opposite order of testing on versus off TPM, our results clearly show a performance decrement while patients are taking TPM, without respect to which condition is tested first.
Lee
Suzee
S
McGill University, Montreal Neurological Hospital, Montreal, Quebec, Canada.
Sziklas
Viviane
V
Andermann
Frederick
F
Farnham
Sara
S
Risse
Gail
G
Gustafson
Mary
M
Gates
John
J
Penovich
Patricia
P
Al-Asmi
Abdullah
A
Dubeau
Francois
F
Jones-Gotman
Marilyn
M
D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use*; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000139:chemically induced; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D004827:Epilepsy / Q000175:diagnosis / Q000188:drug therapy*; D005260:Female; D005632:Fructose / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000187:drug effects; D000077236:Topiramate; D014706:Verbal Learning / Q000187:drug effects
D000927:Anticonvulsants; D000077236:Topiramate; D005632:Fructose