Use of antiepileptic drugs tied to progressive balance dysfunction

By Shannon Aymes

NEW YORK (Reuters Health) - Chronic use of antiepileptic medications (AEDs) is associated with progressive balance dysfunction, according to a small study.

"As older adults have a high rate of epilepsy, these drugs gets prescribed and knowing the balance risks helps to improve safety for these patients," said Dr. Joseph I. Sirven, who chairs the department of neurology at the Mayo Clinic in Arizona and was not involved in the new research.

"Moreover, epilepsy patients as well as older adults have increased risk of osteoporosis," he told Reuters Health by email.

For their study, online October 29 in Epilepsia, Dr. Baemisla Shiek Ahmad of the University of Melbourne in Australia and colleagues examined 26 AED exposure-discordant same-gender twin and sibling pairs on two occasions at least one year apart. The patients were between 18 and 75 years old, and 77% were women.

AEDs were used for epilepsy in 84%; participants also reported AED use for mood stabilization, migraine, and trigeminal neuralgia. The median duration of AED therapy was 19 years.

AED users had significantly more baseline sway as measured by posturography for all scenarios, especially mediolateral tilting with distraction and anteroposterior tilting. Likewise, at followup AED users had more sway on anteroposterior tilting with distraction, mediolateral tilting, and stable platform with distraction than did non-users.

Patients on AEDs also had significantly more deterioration over time for anteroposterior tilting with distraction; a higher baseline sway was predictive of the sway deterioration.

AED use was associated with more static sway on Lord's Balance Test for one scenario at baseline and two scenarios for follow-up, but the annual deterioration rate did not differ between the groups.

There were no differences between the groups for dynamic clinical balance testing or in quadriceps muscle strength. The researchers did find that participants on AEDs performed the Four-Square-Step Test for balance more slowly at baseline and followup, however.

"The etiology of balance dysfunction associated with AED use has not been well elucidated," the authors note in their article. "This may arise from interruptions within the sensorimotor coordination systems regulating balance function (e.g. visual, vestibular system, proprioception, and cerebellar). AED therapy has been shown to affect coordination of eye movement control, and other visual disturbances, as well as postural and motor disturbances (e.g. vestibulocerebellar, dyskinesias, and tremor)."

Dr. Sirven told Reuters Health, "The main message is that imbalance is a very real risk of these AEDs and is often not considered."

Dr. Ahmad did not respond for comment.

SOURCE: https://bit.ly/1SKS1kv

Epilepsia 2015

(c) Copyright Thomson Reuters 2015. Click For Restrictions - https://about.reuters.com/fulllegal.asp