title: Measurement of the effect of a bolus dose of intrathecal baclofen by a repetitive movement test.
abstract: We assessed the repetitive movement (RM) test for measuring the effect of a trial bolus dose of intrathecal baclofen on spasticity. The RM test measures passive range of motion (ROM) by electrogoniometry and stretch reflex activity (SRA) of the flexors and extensors of the knee and ankle by surface electromyography. The SRA has a dynamic component (dynamic stretch reflex, DSR) and a tonic component (tonic stretch reflex, TSR). Four hypotheses were formulated: (a) RM results show a negative relationship between SRA and ROM; (b) values on the RM test are correlated with clinical scores of tonus and spasticity; (c) RM results show a reduction in SRA after administration of the clinically optimal dose of baclofen; and (d) RM results show a dose-dependent effect of intrathecal baclofen on SRA. Twenty-four patients were selected because they had impairments and disabilities caused by intractable spasticity. A bolus of baclofen was administered with incremental doses (25-150 micrograms) until an optimal effect or no effect was obtained. The main outcome measures were RM test and clinical assessments of the Ashworth and spasm score. The results were (a) For the ankle a negative correlation was found between ROM and TSR of the flexor and extensors; for the knee a significant negative correlation was found only with the DSR of the biceps femoris. (b) A positive correlation was found between the Ashworth score and TSR of the extensors and between the spasm score and DSR and TSR of the gastrocnemius muscle. (c) Significant differences were found between baseline measurements and the optimal dose of baclofen for all measures. (d) A significant dose-dependent effect of intrathecal baclofen on the level of SRA was observed. The RM test is thus a useful clinical tool for objectively measuring the effect of intrathecal baclofen administration on spasticity in patients with an upper motor neuron syndrome.
authors.affiliation: Department of Rehabilitation Medicine, Vrije Universiteit, Amsterdam, The Netherlands.
authors.forename: J G
authors.initials: JG
authors.lastname: Becher
authors.forename: G J
authors.initials: GJ
authors.lastname: Lankhorst
authors.forename: C A
authors.initials: CA
authors.lastname: van Bennekom
authors.forename: T W
authors.initials: TW
authors.lastname: Vogelaar
mesh_terms: D000293:Adolescent; D000328:Adult; D000843:Ankle Joint / Q000503:physiopathology; D001418:Baclofen / Q000008:administration & dosage* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004576:Electromyography; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D007719:Knee Joint / Q000503:physiopathology; D007866:Leg; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000187:drug effects*; D009125:Muscle Relaxants, Central / Q000008:administration & dosage* / Q000627:therapeutic use; D009128:Muscle Spasticity / Q000188:drug therapy* / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000503:physiopathology; D016059:Range of Motion, Articular; D012026:Reflex, Stretch
chemical_list: D009125:Muscle Relaxants, Central; D001418:Baclofen