Abstract
Objective: To identify how healthy individuals and those who present both asymptomatically and with persistent symptoms post-concussion group on the basis of their performances across cervical musculoskeletal and sensorimotor (cervical, vestibular, oculomotor, balance) assessments.
Design: Cohort study. Setting: Tertiary teaching hospital, and University.
Participants: 72 individuals (35 asymptomatic and 37 symptomatic) 4 to 26 weeks post a diagnosed concussion and 39 healthy controls with no prior concussion history, aged 18–60 years. Individuals with prior history of cervical spine or vestibular disorders were excluded.
Outcome Measures: Measures of cervical (flexor endurance, segmental joint dysfunction, kinematics) and sensorimotor function (joint position sense, smooth pursuit gain, presence of ≥2 oculomotor indicators of dysfunction with video nystagmography, near point convergence, single-dual tandem walk test time difference, postural sway) were included in a Ward’s hierarchical agglomerative clustering analysis. Dissimilarities were calculated using Gower’s Distance and Agglomerative Coefficients (AC) examined strength of clustering structures.
Main Results: Four clusters (AC=0.96) ranging from minimal or nil impairments (Cluster 1) to multiple impairments across subsystems (Cluster 4) were identified. Most healthy controls (71.8%), and minority of symptomatic individuals (7.7%) grouped in Cluster 1 whereas the opposite occurred in Cluster 4 (43.2% symptomatic, 5.1% healthy controls). Asymptomatic individuals were distributed across all four clusters.
Conclusion: Participants post-concussion, including those not reporting ongoing symptoms, present with patterns of dysfunction consistent with cervical and or sensorimotor impairment. Future research should aim to identify and manage these individuals to better inform decisions related to recovery and return to pre-injury activities post-concussion.