Study Highlights the Importance of Delaying Return to Activities in Symptomatic Concussion Patients

By Aaron Lobsenz. This article was initially published in our Concussion Update newsletter; please consider subscribing.

A paper published in the Journal of Neurotrauma found that children with persistent symptoms had imaging “evidence of ongoing microstructural reorganization or neuroinflammation,” highlighting the importance of delaying a child’s return to play following a concussion if symptoms are persisting. Authors Athena Stein et al. studied 139 children over a three-month period and found that the orientation dispersion index (ODI)––a measure of the displacement of structures attached to neurons—was higher in children with persistent symptoms at 1 and 2-3 months after a concussion compared to children “who displayed clinical recovery,” (no symptoms) at 1 and 2-3 months post-concussion, and a healthy control group. The research team noted that higher ODI in participants with persisting symptoms resulted from poorer white matter microstructural organization, potentially contributing to executive dysfunction, other persisting cognitive symptoms, and worse clinical outcomes. 

The researchers utilized neurite (a protrusion from neurons) orientation and dispersion detection imaging (NODDI), a type of diffusion tensor imaging (DTI), focusing on the orientation dispersion index (ODI). The group measured patients at one month and 2-3 months post-concussion. They found that ODI was significantly elevated in the group with persisting symptoms and progressively decreased between the first month and the second to third months as the children recovered. Stein et al. believe this decrease over time indicates the brain progressively organizing white matter, aided by increased neuroplasticity in children. In addition, levels of ODI measured at the one-month mark were a meaningful predictor of whether participants would have symptoms 2-3 months post-injury. The elevated ODI suggests continued dispersion in neurite orientation and further microstructural reorganization in the symptomatic group; the authors found higher ODI in all investigated brain regions, including in white matter in this group with persisting symptoms. An article in Medical Express noted that while children who displayed clinical recovery at one month had lower ODI than those who remained symptomatic, their ODI was higher than healthy controls.

The researchers also compared ODI to other testing models and found that ODI could better predict recovery than other methods, including fractional anisotropy and free-water isotropic volume fraction. Therefore, researchers should further consider assessing the effectiveness of NODDI and ODI, as they found it to be a better predictor of recovery than other methods––providing a pathway to other methods to investigate concussions.