Identifying Trends of Dysautonomia Signs and Symptoms Associated with Protracted Concussion Recovery during the Buffalo Concussion Treadmill Test: A Retrospective Study

Abstract

To identify trends of provoked dysautonomia signs and symptoms during the Buffalo Concussion Treadmill Test (BCTT). This is a retrospective cohort study of 101 patient charts post-concussion who were screened for suspected dysautonomia. Patients with suspected dysautonomia were assessed for exercise intolerance using a BCTT. Symptoms and rate of perceived exertion were recorded on a standardized form. Digital pulse oximetry was used to collect heart rate (HR) and oxygen saturation. Descriptive analyses were conducted on BCTT results. Of 101 patient charts, 57 were excluded from analysis, including four patients who completed the BCTT by asymptomatically reaching the target HR zone for their estimated HR max. The remaining 44 patients demonstrated: 35 (79.5%) poor HR stabilization defined as a drop or plateau in HR during exercise, 28 (63.8%) exacerbated concussion symptoms, 13 (29.5%) autonomic nervous system response such as hot flushed sensation, 12 (27.3%) rebound symptoms during recovery phases, and 8 (18.2%) desaturation of 90% or below. The mean delta (80% expected HR max – 80% achieved HR max) on the initial test was 80.66 (± 23.08) beats per minute. This study is the first to identify trends of signs and symptoms during the BCTT in an expanded population with suspected dysautonomia after concussion. Future studies are indicated to validate these findings and contribute to development of modified termination criteria for the BCTT in individuals with suspected dysautonomia associated with protracted concussion recovery.