Comparison of clinical and neurophysiologic responses to intrathecal baclofen bolus administration in moderate-to-severe spasticity after acquired brain injury.
OBJECTIVE
To compare clinical and neurophysiologic responses to intrathecal baclofen (ITB) bolus injection in subjects with spasticity after acquired brain injury.


METHODS
Prospective case series.


METHODS
Tertiary care rehabilitation center.


METHODS
Thirty consecutive ITB pump candidates with dysfunctional spasticity caused by traumatic brain injury, hypoxic encephalopathy, or stroke.


METHODS
A single 50-microg ITB bolus.


METHODS
Lower-extremity Ashworth Scale score at 2, 4, and 6 hours after ITB bolus; soleus Hoffmann reflex (H-reflex)/M-wave amplitude (H/M) ratio and abductor hallucis F-wave persistence and F/M ratio at 5 hours. Nonparametric repeated-measures analysis of variance and paired t test were used for statistical analyses.


RESULTS
The Ashworth score on the more involved side significantly decreased from 2.4+/-0.7 at baseline to 1.5+/-0.6 and 1.4+/-0.6 at 4- and 6-hour evaluations, respectively (P<.001). H/M ratio significantly decreased bilaterally (more involved side, 62%+/-28% to 14%+/-19%; less involved side, 59%+/-26% to 11%+/-20%; P<.001). F-wave persistence significantly decreased on the more involved side (86%+/-17% to 75%+/-13%, P<.05) with no change in F/M ratio. There was no significant correlation among these outcome measures before or after the ITB bolus injection.


CONCLUSIONS
H/M ratio is more sensitive than the Ashworth score or F-wave persistence in detecting a physiologic response to ITB bolus. H-reflex is useful for verification of ITB bolus administration, as an adjunct to clinical evaluation, particularly among patients with moderate spasticity at rest or with small changes in Ashworth score. However, potential application of the marked sensitivity of the H-reflex to other clinically challenging situations, such as early detection of possible ITB system malfunction, awaits further investigation.
Stokic
Dobrivoje S
DS
Center for Neuroscience and Neurological Recovery, Methodist Rehabilitation Center, Jackson, MS 39216, USA. dstokic@mmrcrehab.org
Yablon
Stuart A
SA
Hayes
Antonio
A
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001418:Baclofen / Q000008:administration & dosage*; D001930:Brain Injuries / Q000150:complications* / Q000175:diagnosis; D004305:Dose-Response Relationship, Drug; D004576:Electromyography; D005260:Female; D005500:Follow-Up Studies; D006181:H-Reflex / Q000187:drug effects; D006801:Humans; D007278:Injections, Spinal; D015601:Injury Severity Score; D008297:Male; D008875:Middle Aged; D009125:Muscle Relaxants, Central / Q000008:administration & dosage*; D009128:Muscle Spasticity / Q000188:drug therapy* / Q000209:etiology* / Q000503:physiopathology; D011336:Probability; D011446:Prospective Studies; D012047:Rehabilitation Centers; D018570:Risk Assessment; D012720:Severity of Illness Index; D016896:Treatment Outcome
D009125:Muscle Relaxants, Central; D001418:Baclofen