Test-retest reliability of an instrumented electronic walkway system (GAITRite) for the measurement of spatio-temporal gait parameters in young patients with Friedreich's ataxia

Background: Friedreich ataxia (FRDA) affects the spatio-temporal parameters (STP)of gait. To our knowledge, proper tools to measure the variability of ataxic gait have not been validated yet. The aims of the present study were: (1) to measure the reproducibility of STP and gait scores in young patients with FRDA and (2) to describe the characteristics of gait parameters in this population. Methods: Thirty-six patients (18 males, 18 females) with diagnosis of FRDA (mean age 16.4 +/- 4.5 years) were asked to walk barefoot at a self-selected pace along the pressure sensitive walkway (GAITRite (R)). Three trials were recorded for each patient and repeated 48 h later. Collected data was put into statistical analysis tests to determine reliability and variability of STPs and two other gait scores: The Functional Ambulation Performance score (FAP) and the Gait Variability Index (GVI). Results: All STPs showed strong or very strong reliability (ICC > 0.7) and a low variability. The two parameters showing the lowest reliability (0.71 and 0.74) were the base of support and the foot progression angle. The FAP score and the GVI showed strong reliability (ICC > 0.8). Conclusions: The GAITRite system allows feasible and reliable measurements of gait parameters in young patients with FRDA. Lower reliability found for the weakest parameters was attributed to the software automatic errors and the ankle laxity noted in every patient.