EFFECTIVENESS OF GABAPENTIN IN CONTROLLING SPASTICITY - A QUANTITATIVE STUDY

The purpose of this investigation was to study the effectiveness of ga bapentin in controlling spasticity in persons with spinal cord injury (SCI) using a surface EMG-based quantitative assessment technique call ed the brain motor control assessment (BMCA). Six men from a Veterans Affairs Medical Center with spasticity due to traumatic SCI were studi ed as part of a multi-center, placebo-controlled, cross-over, clinical trial of gabapentin. Spasticity was evaluated using multi-channel sur face EMG recordings of muscles in the lower extremities, abdomen and l ow back before and during treatment with oral gabapentin or placebo. G abapentin or placebo was given orally in doses 400 mg three times dail y for 48 h. Following a 10 day wash-out period subjects were crossed-o ver to receive the medication not received the first time. This was fo llowed by an elective open-label extension. Group results during the c ontrolled trial did not reach statistical significance at the dosage u sed. One subject demonstrated a dramatic improvement in spasticity tha t was apparent both clinically and with the BMCA. Other subjects demon strated modest improvements which were seen in the BMCA but not recogn ized clinically. During the open label extension, the four subjects wh o participated experienced important clinical improvements with higher doses (to 3600 mg/day). These improvements were often in components o f spasticity in which the BMCA had detected subclinical changes during the cross-over trial. A seventh subject was studied using the BMCA at doses of 1200 mg T.I.D. gabapentin, off gabapentin and 800 mg T.I.D. gabapentin and demonstrated quantitatively a dose-related effect with higher doses of gabapentin which matched clinical observations. Gabape ntin at doses of 400 mg T.I.D. may be effective in controlling some fe atures of spasticity in persons with SCI. Higher doses provide greater control of spasticity, and controlled studies using higher doses are needed to evaluate gabapentin's efficacy.