Postconcussion Dizziness, Sleep Quality, and Postural Instability: A Cross-Sectional Investigation

Abstract

Context Dizziness, poor sleep quality, and postural instability are all commonly reported postconcussion and individually relate to poor outcomes. Objective To examine sleep quality and postural stability among adolescents who did and those who did not report dizziness within 2 weeks of concussion. Design Cross-sectional study. Setting Research laboratory. Patients or Other Participants Participants were individuals 12 to 18 years old and either within 14 days of concussion (n = 58; girls = 29, boys = 29, age = 15.2 ± 1.8 years, time postinjury = 7.1 ± 3.1 days) or uninjured control recruits (n = 73, girls = 31, boys = 42, age = 15.8 ± 1.3 years). Main Outcome Measure(s) Participants rated preinjury and current dizziness using the Post-Concussion Symptom Inventory (PCSI) and current sleep quality using the Pittsburgh Sleep Quality Index. They also completed postural stability assessments (single-task and dual-task tandem gait and modified Balance Error Scoring System[mBESS]). Results We divided patients with concussion into dizzy (n = 21) or not-dizzy (n = 37) groups based on PCSI dizziness ratings (difference between current and preinjury dizziness rating: dizzy = >3, not dizzy = <3). The dizzy and not-dizzy groups both reported worse sleep quality compared with the control group (Pittsburgh Sleep Quality Index score: dizzy = 9.6 ± 3.7 versus not dizzy = 7.2 ± 3.5 versus control = 4.3 ± 2.6; P < .001) via univariable comparison. Similarly, the dizzy group performed slowest, followed by the not-dizzy group, and then the control group on single-task tandem gait (dizzy = 27.2 ± 11.7 seconds versus not dizzy = 21.2 ± 6.3 seconds versus control = 14.7 ± 3.6 seconds, P < .001) and dual-task tandem gait (dizzy = 38.4 ± 16.2 seconds versus not dizzy = 29.9 ± 7.2 seconds versus control = 21.6 ± 7.5 seconds, P < .001). Both concussion groups demonstrated more errors than the control group on the mBESS (dizzy = 9.8 ± 5.1 versus not dizzy = 6.9 ± 5.8 versus control = 3.8 ± 3.5, P < .001). After controlling for total symptom severity in the multivariable model, we observed that tandem gait, but not mBESS score or sleep quality, was associated with dizziness. Conclusions Individuals with postconcussion dizziness demonstrated impaired tandem-gait performance, whereas poor sleep quality was associated with total symptom severity. Identifying and treating the underlying dysfunction contributing to dizziness and postural instability may guide customized rehabilitation strategies and facilitate recovery.