Gait variability is altered in patients with peripheral arterial disease

18 Objective. Claudication is the most common presentation of peripheral arterial disease producing 19 significant ambulatory compromise. Claudicating patients, the majority of which are elderly, 20 have reduced mobility and poor health outcomes, including increased risk of falls. The gait of 21 elderly fallers is characterized by increased variability. Increase in the variability of the 22 locomotor system makes gait more noisy and unstable. The purpose of this study is to investigate 23 gait variability in PAD patients. 24 Design/Methods: Nineteen symptomatic PAD patients (age: 63.6 ± 9.8 years, body mass: 82.1 ± 25 18.5 kg, body height: 1.71 ± 0.06 m) walked on a treadmill in the absence of pain or claudication 26 symptoms while joint flexion and extension kinematics were captured. Results were compared to 27 those obtained from 17 matched healthy controls (age: 65.2 ± 12.5 years, body mass: 82.0 ± 28 25.9.5 kg, body height: 1.73 ± 0.08 m). Relative joint angles were calculated for the ankle, knee 29 and hip flexion/extension and the stride to stride variability of joint flexion and extension was 30 calculated from at least 30 consecutive footfalls. Variability was expressed using the largest 31 Lyapunov Exponent, standard deviation and coefficient of variation. Independent t-tests were 32 used to compare gait variability between groups. 33 Results. Symptomatic PAD patients had significantly higher Lyapunov Exponent values and 34 coefficient of variation values for all joints, and higher standard deviation values at the ankle and 35 the hip (P < 0.05). 36 Conclusions: Symptomatic PAD patients have increased gait variability at the ankle, knee, and 37 hip joints at baseline ambulation in the absence of claudication pain. Our findings indicate 38 significant baseline deterioration in the locomotor system of symptomatic PAD patients. This 39 deterioration results in increased noise and instability of gait and is a potential contributing factor 40 to the falls and mobility problems experienced by the symptomatic PAD patients. 4