Gait abnormalities of COPD are not directly related to respiratory function

To assess whether gait abnormalities in COPD depend on mere impairment of respiratory function.

In 40 patients with COPD at different GOLD stages and 28 controls, we evaluated: forced expiratory volume in 1s (FEV1); partial pressure of oxygen; Mini-Mental State Examination (MMSE); dynamic balance through the Mini-BESTest (MBT); Timed Up and Go (TUG) test without and with dual task counting aloud back by three; 6-min walk test (6MWT); body sway during quiet stance (stabilometry); spatial-temporal variables of gait by a 4-m long sensorized walkway (baropodometry). Lower-limb muscle strength, tendon reflexes, and sensation were also clinically evaluated.

Muscle strength of proximal but not distal muscles was slightly reduced in patients, whereas reflexes and sensation were unaffected. FEV1, partial pressure of oxygen, MMSE, MBT, stabilometry, as well as baropodometry, were abnormal and unrelated to muscle weakness. The time taken to perform the TUG test was increased, and to a larger extent with than without dual task. At baropodometry, variability of step length was increased; abnormalities of gait variables were associated with larger body sway but not with FEV1 or hypoxemia. Gait speed at 6MWT was correlated with MBT score and with FEV1 as well as hypoxemia.

6MWT findings give a measure of gait disability linked to endurance-related respiratory failure. Gait at baropodometry is associated with impairment of balance, cognitive status and abnormal dual task performance. We suggest that central nervous lesions, presumably of vascular origin, are detrimental to balance and gait in COPD.