National rehabilitation hospital limb classification for exercise, research, and clinical trials in post-polio...

A need exists for an objective classification of polio patients for clinical and research purposes that takes into account the focal, asymmetric, and frequent subclinical nature of polio lesions. In order to prescribe a safe, effective exercise program, we developed a five-level (Classes I-V) limb-specific classification system based on remote and recent history, physical examination, and a four-extremity electrodiagnostic study (EMG/NCS). Class I limbs have no history of remote or recent weakness, normal strength, and a normal EMG. Class II limbs have no history of remote or recent weakness (or if remote history of weakness, full recovery occurred), normal strength and EMG evidence of prior anterior horn cell disease (AHCD). Class III limbs have a history of remote weakness with variable recovery, no new weakness, decreased strength, and EMG evidence of prior AHCD. Class IV limbs have a history of remote weakness with variable recovery, new clinical weakness, decreased strength, and EMG evidence of AHCD. Class V limbs have a history of severe weakness with little-to-no recovery, severely decreased strength and atrophy, and few-to-no motor units on EMG. In a prospective study of 400 limbs in 100 consecutive post-polio patients attending our clinic, 94 (23%) limbs were Class I, 88 (22%) were Class II, 95 (24%) were Class III, 75 (19%) were Class IV, and 48 (12%) were Class V. Guidelines for the use of this classification in a clinical/research setting are presented along with sample case histories and class-specific exercise recommendations.