• Dobrivoje S Stokic, Stuart A Yablon, and Antonio Hayes.
• Center for Neuroscience and Neurological Recovery, Methodist Rehabilitation Center, Jackson, MS 39216, USA. dstokic@mmrcrehab.org
• Arch Phys Med Rehabil. 2005 Sep 1;86(9):1801-6.

ObjectivesTo compare clinical and neurophysiologic responses to intrathecal baclofen (ITB) bolus injection in subjects with spasticity after acquired brain injury.DesignProspective case series.SettingTertiary care rehabilitation center.ParticipantsThirty consecutive ITB pump candidates with dysfunctional spasticity caused by traumatic brain injury, hypoxic encephalopathy, or stroke.InterventionA single 50-microg ITB bolus.Main Outcome MeasuresLower-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.ResultsThe 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.ConclusionsH/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.

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