Quantitative study on effects of baclofen on muscle spasticity in Multiple Sclerosis

Spasticity is clinically defined as velocity-dependent resistance to passive movement, characterized by excessive, jerky contraction of muscles. However, spasticity is not yet well understood, and current clinical measures of it are subjective and unreliable. We applied standard physics principles and phase space analyses to better visualize the motor impairments associated with spasticity in Multiple Sclerosis patients, at the VA Hospital in Washington, DC. Testing was conducted at baseline and then again after one month of de novo baclofen administration in order to determine whether this improved the patients´ condition. Two analytical methods were used: (1) Phase Area Ratio (PAR) and (2) Spontaneous Accelerative Transients (SAT). The SAT analyses showed a small decrease in spasticity after baclofen use, while the PAR analyses and clinical measures showed no significant change. Although they provided differing results, this study shows that spasticity during active joint motions can be more reliably quantified through analytical methods. The PAR and SAT metrics may be applicable to a variety of physiological signals.