Concurrent validity of an automated algorithm for computing the center of pressure excursion index (CPEI)

Area of Science:

• Biomechanics
• Podiatry
• Gait Analysis

Background:

• The Center of Pressure Excursion Index (CPEI) assesses dynamic foot function using plantar pressure data.
• Manual correction of exceptions in original CPEI calculation programs introduced user variability.
• A need exists for a faster, more consistent method for CPEI computation.

Purpose of the Study:

• To compare CPEI values calculated by a new automated program versus an original manual program.
• To validate the accuracy and reliability of the automated CPEI algorithm.
• To assess the applicability of the automated program for both asymptomatic and pathologic populations.

Main Methods:

• Developed a new, fully automated algorithm to calculate CPEI, addressing exceptions in computational rules.
• Collected barefoot plantar pressure data during walking from 61 asymptomatic adults, 19 diabetic adults with hallux valgus, and 13 adults with mild hallux valgus.
• Analyzed right foot data using linear regression and Bland-Altman plots to compare CPEI values from both programs.

Main Results:

• The automated algorithm produced CPEI values linearly related to the original program (R²=0.99; P<0.001).
• Bland-Altman analysis showed minimal differences (0.55%) between the two CPEI computation methods.
• The automated program demonstrated high agreement with the original program across diverse subject groups.

Conclusions:

• The new automated algorithm provides a reliable and accurate method for calculating CPEI.
• This automated approach minimizes rater discretion and enhances calculation speed.
• The validated automated algorithm is suitable for assessing dynamic foot function in both healthy and pathologic individuals.