Entropy metrics for analyzing trunk movement regularity in chronic non-specific low back pain: Insights from a systematic review

BackgroundChronic nonspecific low back pain (CNLBP) is linked to changes in trunk motor control, often presenting as increased movement regularity. Entropy-based metrics quantify such alterations in motor variability, yet evidence remains fragmented.ObjectiveThe present study aims to systematically review studies employing entropy measures to assess trunk movement regularity in individuals with and without CNLBP.MethodsA comprehensive search was conducted across nine databases, including PubMed, Scopus, and Embase. Cross-sectional studies comparing CNLBP participants to healthy controls were included. Two independent reviewers handled study selection, data extraction, and risk of bias assessment.ResultsFive studies (n =222) met the inclusion criteria. Of the 222 participants in the pooled dataset, 42% were healthy controls and 58% had CNLBP, with an age range of 24.5 to 56.75 years. The weighted mean age across studies was approximately 43 years. Higher entropy (i.e., lower regularity) was observed in postural and gait tasks among CNLBP individuals. Conversely, reduced entropy (i.e., higher regularity) was noted in flexion-extension tasks, highlighting task-specific motor adaptations.ConclusionCNLBP is associated with task-dependent alterations in trunk movement regularity. Future research should standardize entropy computation and data collection protocols to enhance study comparability and clinical applicability.