Abnormal Turning and Its Association with Self-Reported Symptoms in Chronic Mild Traumatic Brain Injury

Abstract

Turning is common in daily activity and requires rapid, coordinated reorientation of the head, trunk, and pelvis toward the new direction of travel. Yet, turning gait has not been well explored in populations with mild traumatic brain injury (mTBI) who may alter their turning behavior according to self-perceived symptoms or motor dysfunction. The purpose of this study was to examine turning velocities and coordination in adults with chronic mTBI (>3 months post-injury and still reporting balance complaints) during a task simulating everyday ambulation. We hypothesized that individuals with chronic mTBI would reduce their angular velocity when turning and increase the variability of head-pelvis coordination compared with controls, and that the reduction in velocity and increased variability would be associated with their self-reported symptom score. Forty-two adults (14 chronic mTBI, 28 controls) completed the Neurobehavioral Symptom Inventory before walking 12 laps around a marked course containing two 45-degree turns, four 90-degree turns, and two 135-degree turns. Inertial sensors collected angular velocities of the head and pelvis. After adjusting for covariates, participants with chronic mTBI had significantly slower lap times and peak angular velocities of the pelvis (p < 0.01) compared with the control group. The peak velocity timing (PVT) between peak velocities of the head and pelvis, and the variability of that timing was significantly greater in participants with chronic mTBI (p < 0.01). Within the chronic mTBI group, somatosensory symptoms were associated with slower angular velocities of the head and pelvis (p = 0.03) and increased PVT variability (p < 0.01). The results suggest individuals with chronic mTBI with worse somatic symptoms have impaired head stabilization during turning in situations similar to everyday life. These results encourage future research on turning gait to examine the causal relationship between symptoms and daily locomotor function in adults with chronic mTBI.

Keywords: brain injury; gait; head stabilization; inertial sensors; turning.

Conflict of interest statement

No competing financial interests exist.

Figures

FIG. 1.

Turning course marked with arrows including four 45-degree turns, four 90-degree turns, and two 135-degree turns. Two 45-degree turns (x) were excluded, leaving eight total turns per lap.

FIG. 2.

Example angular velocity traces of the head (top), trunk (middle), and pelvis (bottom). The peak angular velocity for each turn is indicated with a filled marker. The head-to-trunk and head-to-pelvis peak velocity timings (HT-PVT and HP-PVT, respectively) are indicated by the temporal difference between the peak velocities at each turn.

FIG. 3.

Box and scatter plot of the variability in head-to-pelvis peak velocity timing (HP-PVT) for the chronic mild traumatic brain injury (mTBI) and control groups. A significant difference was found between groups (p = 0.001). HP-PVT variability was defined as the standard deviation, across all turns, of the temporal difference between peak head and pelvis angular velocities.

FIG. 4.

Scatter plots of (A) self-selected gait speed obtained from a straight walking test, (B) variability of the head-to-pelvis peak velocity timing (HP-PVT), (C) peak head angular velocity, and (D) peak pelvis angular velocity versus the Neurobehavioral Symptom Inventory (NSI) somatosensory symptom score in the chronic mild traumatic brain injury (mTBI) group only. For (C) and (D), green circles, blue triangles, and yellow squares indicate 45-degree, 90-degree, and 135-degree turns, respectively. Self-selected straight gait speed was not associated with NSI somatosensory symptom scores before (R2 = 0.006) or after (p = 0.506) adjusting for covariates. PVT variability was significantly associated with higher NSI somatosensory symptom scores before (R2 = 0.504) and after (p = 0.009) adjusting for covariates. Peak head angular velocity was significantly associated with higher NSI somatosensory symptom scores before (R2 = 0.398 for 45-degree turns, R2 = 0.401 for 90-degree turns, R2 = 0.230 for 135-degree turns) and after (p < 0.001) adjusting for covariates. Peak pelvis angular velocity was significantly associated with higher NSI somatosensory symptom scores before (R2 = 0.258 for 45-degree turns, R2 = 0.381 for 90-degree turns, R2 = 0.245 for 135-degree turns) and after (p = 0.002) adjusting for covariates. Color image is available online at www.liebertpub.com/neu

FIG. 5.

Peak pelvis angular velocity for each group stratified by turning angle and speed. A significant group*speed interaction was found (p < 0.001) with controls increasing their peak angular velocity across speeds more than the chronic mild traumatic brain injury (mTBI) group. Lines between the normal and fast speed correspond to each participant at each turning angle. Color image is available online at www.liebertpub.com/neu