Continuous intrathecal baclofen infusions induced a marked increase of the transcranially evoked silent period in a patient with generalized dystonia

We observed a marked prolongation of the transcranially evoked silent period during continuous intrathecal administration of high doses of the gamma-aminobutyric acid (GABA)_B receptor agonist baclofen in a patient with generalized dystonia. Size of motor evoked potentials and central conduction time remained unchanged during intrathecal baclofen administration. The selective prolongation of the silent period during high-dose continuous intrathecal baclofen therapy supports the notion that GABA_B-ergic intracortical interneurons play a part in the generation of the transcranially evoked silent period. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21:1209–1212, 1998.