The reliability of physical performance measures in peripheral neuropathy

The purpose of this study was to evaluate the test-retest reliability of select physical performance measures among people with peripheral neuropathy (PN).

20 PN patients (12 women, 8 men, mean age=68.4+/-12.5 years) were assessed on two separate occasions. Plantar pressure sensitivity was determined with a monofilament of known strength. Functional capacity and mobility were measured by the 6-min walk (6MW) and timed up-and-go (TUG) tests, respectively. Standing balance was evaluated by computing the average velocity (VEL) and area enclosing 95% of the body COP (A95) while participants stood quietly with eyes closed for multiple trials of varying length. Isokinetic knee extensor and flexor peak torque (KEPT, KFPT) were measured with an dynamometer during five maximal voluntary contractions.

Plantar sensitivity and all measures of physical function demonstrated significant reliability. High reliability was observed for the 6MW (ICC=0.94) and the two-trial average TUG (ICC=0.99). Similarly, KEPT and KFPT were highly reliable whether using the top trial, or averaging the three best trials (ICCs>0.96). Averaging multiple standing balance trials generally increased ICC values, with 30s trials appearing to possess the highest reliability.

Despite the heterogeneity of the PN population, select measures of physical performance are highly reliable and therefore recommended for use when examining physical function in these patients.