Functional evaluation of lower limbs and balance in adults with poliomyelitis and post-polio syndrome

Abstract

Introduction: Acute anterior poliomyelitis (AAP) is one of the main neuropathies and the post-polio syndrome (PPS) is among the late effects of AAP. The main clinical manifestations of AAP/SPP – reduced muscle strength, fatigue, joint and muscle pain, most
often in the lower limbs – can be directly related to poor postural control. Few studies have investigated postural control in adults with AAP/PPS. Recent studies in healthy subjects showed the role of interjoint coordination to maintain the postural balance, but the interjoint coordination of lower limbs in patients with AAP/PPS remains unknown. Objective: To assess orthostatic postural control in adults with AAP/PPS using the kinematic mapping of interjoint coordination of the lower limbs and to associate postural stability to clinical and functional outcomes of patients. Methods: This observational, cross-section controlled study included 16 adults with AAP/PPS and other 18 healthy adults as the control group. Participants underwent a clinical examination and were evaluated regarding: muscle strength using the Medical Research Council (MRC) scale; postural stability using the Berg Balance Scale
(BBS) and the Fall Efficacy Scale (FES-I); interjoint coordination of the lower limbs (ankleknee; ankle-hip, knee-hip) through the kinematic analysis with an optoelectronic system. The kinematic signals were processed for visualization, location and quantification of regions in the support base related to postural modes (in-phase: positive correlation; anti-phase: negative correlation) of interjoint coordination. Results: AAP/PPS patients had motor sequelae located mostly in the lower limbs, being fatigue and muscle atrophy the most frequent symptoms, as well as pain, difficulty in performing activities of daily living, intolerance to cold, sleep disorders, dysphonia and/or dysphagia and breathing difficulties. Compared to the control group, patients had lower (all P<0.001) muscle strength (MRC: 17 ± 7 vs. 30 ± 0 points), lower postural stability (BBS: 41 ± 11 vs. 55 ± 1 points) and increased fear of falling (FES-I : 33 ± 12 vs. 19 ± 4 points). Joint angle measurements showed postural transitions between modes occur abruptly and small variations in each phase also varies with time that for all pairs of joints. No significant difference (P>0.05) was observed regarding
kinematic variables between groups, body sides and joint pair, but only for in-phase/antiphase postural modes. Finally, an association between muscle strength, postural stability and difficulties in performing activities of daily living, and between the latter and fear of falling. Conclusion: Adults with AAP/PPS have preserved lower limb interjoint coordination despite functional impairments due to muscle weakness and postural instability.