CONCUSS randomised clinical trial of vergence/accommodative therapy for concussion-related symptomatic convergence insufficiency

Objective: The CONCUSS randomised clinical trial compared the effectiveness of immediate office-based vergence/accommodative therapy with movement (OBVAM) to delayed therapy for the treatment of concussion-related convergence insufficiency (CONC-CI) in participants 11-25 years old with persisting postconcussive symptoms 4-24 weeks post injury. Methods: Symptomatic CONC-CI was diagnosed using clinical signs via near point of convergence (NPC) and positive fusional vergence (PFV) and symptoms via the Convergence Insufficiency Symptom Survey (CISS). Participants were randomised to immediate OBVAM (twice weekly for 6 weeks) or delayed OBVAM (starting 6 weeks after baseline enrolment). After 6 weeks (outcome time 1 assessment), the therapeutic outcomes of NPC, PFV and CISS were assessed and compared between the two groups. After the outcome time 1 assessment, the delayed group received twice-weekly OBVAM sessions for 8 weeks, while the immediate group received an additional 2 weeks of twice-weekly OBVAM sessions. The outcome time 2 assessment compared groups after each group received all 16 OBVAM sessions. Results: In the immediate group, 46/52 (88%) were classified as successful or improved at the outcome time one assessment based on the primary outcome measure, a composite of NPC and PFV, compared with 4/52 (8%) in the delayed group (p<0.001). The mean NPC decreased (improved) by 7.9 cm in the immediate group and 1.8 cm in the delayed group (mean difference at outcome time 1 assessment: 5.1 cm (95% CI: 3.9 to 6.3; p<0.001)). The mean PFV increased (improved) by 17.5Δ in the immediate group and 2.5 in the delayed group (mean difference at outcome time 1 assessment: 15.0Δ (95% CI:11.7 to 18.3); p<0.001). At the outcome time 1 assessment, 41/52 (79%) of the participants in the immediate group had improved symptoms based on CISS scores ≤ preinjury scores or decreased by 10 points or more, compared with only 7/52 (13%) of participants from the delayed group (p<0.001). When comparing dosing in the immediate group, for 12 OBVAM sessions, 88% were classified as successful or improved using the composite measurement of NPC and PFV, which increased to 94% after 16 OBVAM sessions. For the outcome time 2 assessment, when both groups had received 16 OBVAM sessions, no significant difference was observed for NPC, PFV or CISS (p=1.0). Conclusion: OBVAM therapy is effective in improving the NPC, PFV and symptoms in CONC-CI. Immediate initiation of OBVAM compared with delayed initiation shortens the period of symptoms experienced and fosters an earlier return to activities. Trial registration number: clinicaltrials.gov identifier: NCT05262361.