Reliability of the Five Step Assessment and Its Coefficients of Impairment in Spastic Paresis

Objective To determine the intrarater and interrater reliability of the Five Step Assessment (FSA) and its derived coefficients of impairment in chronic spastic paresis. Design Prospective observational study. Setting Study of outpatients followed in a rehabilitation department. Participants In this single-center prospective study, participants (n=18) with chronic hemiparesis (>1y since injury) were evaluated by 4 raters (3 medical doctors, 1 physiotherapist; experience in hemiparesis, 14±9y). Interventions All raters estimated muscle shortening, spasticity, weakness, and fatigability against the resistance of 8 key antagonists in adults twice, one week apart. Main Outcome Measures FSA involves measuring 4 angles: angle of arrest at slow speed of stretch (X V1 ), angle of catch or clonus at fast speed of stretch (X V3 , Tardieu), angle of match between maximal agonist effort and passive and active antagonist resistances (X A ), residual angle of match after 15 seconds of repeated maximal amplitude active efforts (X A15 ), and spasticity grade Y. Four derived coefficients of impairment were studied: coefficients of shortening, C SH= (X N −X V1 )/X N (X N , normally expected maximal passive joint amplitude); of spasticity, C SP =(X V1 −X V3 )/X V1 ; of weakness, C W =(X V1 −X A )/X V1 ; and of fatigability, C F =(X A −X A15 )/X A . Both intraclass correlation coefficients and mean differences were calculated for each parameter. Results Among 18 participants (four women), intrarater reliability was good to excellent (intraclass correlation coefficient >0.75) for all parameters in all muscles. Interrater reliability was good to excellent for all muscles and parameters except for spasticity grade Y and coefficient of fatigability (moderate). Conclusions The 5 parameters and 4 coefficients of impairment of the FSA have moderate-to-excellent intrarater and interrater reliability in chronic spastic paresis.