Peripheral and central effect of baclofen on ankle joint stiffness in multiple sclerosis

Stretch Reflex Regulation in Healthy Subjects and Patients with Spasticity

“…It is generally assumed that both baclofen and diazepam mainly depress the stretch reflex activity through increased GABA‐mediated presynaptic inhibition, but several recent studies have demonstrated that this is not the case. Baclofen activates GABA B receptors, which are found both presynaptically and postsynaptically on motoneurons, and the effect of this drug on spasticity has been found to be explained mainly by decreased excitability of the motoneurons (27,54). This has the effect that a voluntary contraction becomes difficult for the patients, and in some patients, the functional ability is greatly affected.…”

Guided intrathecal baclofen administration by using soleus stretch reflex in moderate-severe spastic multiple sclerosis patients with implanted pump

“…8 In this previous study the amplitude of the stretch reflex was 200 Á/300 mV in untreated spastic MS patients and 150 Á/200 mV in baclofen-treated patients. This indicates that antispastic treatment with intrathecal baclofen is an effective treatment regarding reflex inhibition.…”

“…In general, in this group of patients the amplitude of stretch reflex was very small compared with previous findings in MS patients and controls and was totally missing in 3/12 patients. 8,9 Only 2/9 patients showed any changes in Ashworth score between the two tests despite changes in baclofen dose being seen in 6/9 patients. Consequently, spasticity score by using Ashworth scale is insensitive to detect minor changes in moderate Á/severe spasticity and consequently might not be very useful in evaluating spasticity in relation to ambulatory filling of baclofen pumps.…”

“…8,9 Other biomechanical techniques have been applied in order to quantitate changes in spasticity by antispastic therapy. In a recent study, the effect of an intrathecal bolus injection of baclofen was evaluated by measuring the torque under a circular fibreglass cast attached to a semiflexed knee joint.…”

“…In prior studies from our laboratory baclofen induced a decrease in threshold of the soleus stretch reflex and a 20% decrease in stiffness at the ankle joint recorded in a sitting position and an increase in the soleus stretch reflex threshold in the early swing phase during walking in spastic multiple sclerosis (MS) patients. 8,9 In the present study we tested the hypothesis that changes in soleus stretch reflex were correlated to changes in intrathecal baclofen dose in MS patients with moderate Á/severe spasticity treated with intrathecal baclofen pump.…”