Influence of baclofen upon the alpha-motoneuron in spasticity by means of F-wave analysis.
Intrathecal baclofen dramatically improves severe spastic syndromes. This improvement is likely related to reduced excitability of alpha-motoneurons. To investigate the influence of baclofen upon the alpha-motoneuron, we analyzed F-waves before and after intrathecal baclofen bolus injection (usually 50 micrograms) as well as after administration of different, constantly delivered doses (60-200 micrograms/day). Intrathecal baclofen bolus decreased the maximum F-wave amplitude (Fp) from an initial value of 9% of the maximum M amplitude (Mmax) (= F/M-ratio) to 2.4% of the Mmax after 130-180 min, reduced the mean F-wave amplitude 60% within 150 min, and shortened the mean duration by 40-60% after 130-180 min. Constantly delivered baclofen of 100 micrograms/day reduced the F/M-ratio from 5% to 2%, the mean F-wave amplitude by 40-80%, and the F-wave mean duration by 40-80%. The minimum F-wave latency did not change after bolus or during steady state administration. The findings indicate that the F-wave mean and maximum amplitude as well as the mean duration are altered in a quantifiable manner following intrathecal baclofen application.
Dressnandt
J
J
Neurologic Department, Technical University, Munich, Germany.
Auer
C
C
Conrad
B
B
D001418:Baclofen / Q000494:pharmacology*; D004594:Electrophysiology; D006801:Humans; D007260:Infusion Pumps; D007278:Injections, Spinal; D009046:Motor Neurons / Q000187:drug effects*; D009128:Muscle Spasticity / Q000503:physiopathology*; D011930:Reaction Time
D001418:Baclofen