Conduction velocity distribution estimation using the collision technique—Theory and simulation study

Current nerve conduction studies (NCS) are influenced by the activity of the largest active fibers, making it difficult to assess the state of smaller nerve fibers. This study is aimed at alternative diagnostic techniques for assessing carpal tunnel syndrome (CTS). A conduction velocity distribution (CVD) estimator based on the collision technique that incorporates volume conductor modeling is proposed and discussed in this paper. Simulations were run to evaluate the accuracy of the CVD estimator and compare its performance with previous CVD estimators based on the collision technique. Results show the improved accuracy of the proposed approach, which is able to provide estimates with a percent mean square error (PMSE) lower than 1.1% for all CTS cases studied and lower than 2% in the presence of additive white Gaussian noise. Simulations also showed that conduction slowing in the carpal tunnel (CT) segment is detected by the proposed technique and displayed as an increase in the number of low velocity fibers. Results suggest that both CVD estimator and amplitude parameter proposed can help detect the severity of CTS in a patient more accurately than current NCS.