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Effect of levetiracetam on human corticospinal excitability

From the Human Motor Control Section (Drs. Sohn, Jung, and Hallett) and Human Cortical Physiology Section (Dr. Kaelin-Lang), NINDS, National Institutes of Health, Bethesda, MD; and Department of Neurology and Brain Research Institute (Dr. Sohn), Yonsei University College of Medicine, Seoul, Korea.

Address correspondence and reprint requests to Dr. Mark Hallett, NIH, NINDS, Bldg. 10, Rm. 5N226, 10 Center Drive, MSC 1428, Bethesda, MD 20892-1428.

Objective: — To investigate whether levetiracetam (LTC) alters corticospinal excitability in humans.

Background: — Although the antiepileptic activity of LTC is well recognized, its mechanism of action has yet to be determined. Transcranial magnetic stimulation (TMS) has been used to investigate the pharmacologic effects of various antiepileptic drugs on human corticospinal excitability.

Methods: — The authors performed TMS before and after double-blind administration of 3000 mg LTC or placebo in six healthy volunteers. TMS measurements included resting and active motor threshold (MT), recruitment curve of motor-evoked potential amplitudes, intracortical inhibition, and facilitation using the paired-pulse technique and silent period. F-wave and compound muscle action potential (CMAP) were also measured.

Results: — In recruitment curve measurements, motor-evoked potential amplitude was reduced for LTC with high stimulation intensity (130% and 140% of resting MT) compared with placebo (p < 0.05 and p < 0.01), but not with relatively low stimulation intensity (110% and 120%). The changes in other TMS measurements as well as F-wave and CMAP after LTC did not differ significantly from those observed after placebo administration.

Conclusion: — These results suggest that LTC reduces the corticospinal neuronal response to magnetic stimulation, preferentially affecting less excitable neurons. The lack of change in F-wave and CMAP suggests that this effect is mainly derived from the motor cortex.

This article has been cited by other articles:

				Y. H. Sohn, N. Dang, and M. Hallett Suppression of Corticospinal Excitability During Negative Motor Imagery J Neurophysiol, October 1, 2003; 90(4): 2303 - 2309. [Abstract] [Full Text] [PDF]

				Y. H. Sohn, H. Y. Jung, A. Kaelin-Lang, and M. Hallett Effect of Levetiracetam on Rapid Motor Learning in Humans Arch Neurol, December 1, 2002; 59(12): 1909 - 1912. [Abstract] [Full Text] [PDF]

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