Impaired Neuromotor Control During Gait in Concussed Adolescents-A Frequency Analysis.

Disruptions in gait function are common after concussion in adolescents; however, the neuromotor control deficits driving these gait disruptions are not well known. Fifteen concussed (age mean [SD]): 17.4 [0.6], 13 females, days since injury: 26.3 [9.9]) and 17 uninjured (age: 18.0 [0.7], 10 females) adolescents completed 3 trials each of single-task gait and dual-task gait (DT). During DT, participants simultaneously walked while completing a serial subtraction task. Gait metrics and variability in instantaneous mean frequency in lower extremity muscles were captured by inertial sensors and surface electromyography, respectively. A 2-way analysis of covariance was used to compare gait metrics across groups and conditions. Functional principal components analysis was used to identify regions of variability in instantaneous mean frequency curves. Functional principal component scores were compared across groups using a Welch statistic. Both groups displayed worse performance on gait metrics during DT condition compared to single-task, with no differences between groups (P < .001). Concussed adolescents displayed significantly greater instantaneous mean frequency, indicated by functional principal component 1, in the tibialis anterior, biceps femoris, and semitendinosus (P < .05) during single-task and DT compared with uninjured adolescents. Our observations suggest that concussed adolescents display inefficient motor unit recruitment lasting longer than 2 weeks following injury, regardless of the addition of a secondary task.

Neurophysiological and gait outcomes during a dual-task gait assessment in concussed adolescents.

BACKGROUND: Gait deficits are common after concussion in adolescents. However, the neurophysiological underpinnings of these gait deficiencies are currently unknown. Thus, the goal of this study was to compare spatiotemporal gait metrics, prefrontal cortical activation, and neural efficiency between concussed adolescents several weeks from injury and uninjured adolescents during a dual-task gait assessment. METHODS: Fifteen concussed (mean age[SD]: 17.4[0.6], 13 female, days since injury: 26.3[9.9]) and 17 uninjured adolescents (18.0[0.7], 10 female) completed a gait assessment with three conditions repeated thrice: single-task walking, single-task subtraction, and dual-task, which involved walking while completing a subtraction task simultaneously. Gait metrics were measured using an inertial sensor system. Prefrontal cortical activation was captured via functional near-infrared spectroscopy. Neural efficiency was calculated by relating gait metrics to prefrontal cortical activity. Differences between groups and conditions were examined, with corrections for multiple comparisons. FINDINGS: There were no significant differences in gait metrics between groups. Compared to uninjured adolescents, concussed adolescents displayed significantly greater prefrontal cortical activation during the single-task subtraction (P = 0.01) and dual-task (P = 0.01) conditions with lower neural efficiency based on cadence (P = 0.02), gait cycle duration (P = 0.03), step duration (P = 0.03), and gait speed (P = 0.04) during the dual-task condition. INTERPRETATION: Our findings suggest that several weeks after injury concussed adolescents demonstrate lower neural efficiency and display a cost to gait performance when cognitive demand is high, e.g., while multitasking, suggesting that the concussed adolescent brain is less able to compensate when attention is divided between two concurrent tasks.

Rehabilitation Following Fracture in Dystrophinopathy, A Case Series.

BACKGROUND: Boys with dystrophinopathies (DMD) are at increased risk of low bone mineral density and fracture. Femoral fracture is the most common extremity fracture and is accompanied by significant risk of functional loss. Care considerations for DMD have stressed that aggressive management may be needed to maintain ambulation and that surgical fixation allows early mobilization. OBJECTIVES: Describe 5 cases of femoral fracture in ambulatory boys with DMD and the course of care undertaken to optimize function. PATIENTS: Five boys with DMD median age 15y (12-16) who were independently ambulatory. Median 10m walk speed prior to their first fracture was 8 sec (7-17.37) and 4 of 5 were less than the 9 seconds predictive of 2 year ambulation retention. Three of the cases had a single incident causing fracture; the remaining cases had 2 and 3 incidents respectively representing a total of 8 fractures 6 of which were surgically stabilized. RESULTS: Following the first fracture, all 5 subjects regained some form of ambulation. Three patients regained independent ambulation and 2 with hand held support or contact guard. Two subjects went on to have additional falls with associated fracture. No patient regained the ability to rise from the floor and only one of the 5 regained the ability to climb steps and all demonstrated a decline in walking speed. CONCLUSION: Prompt orthopedic intervention, early mobility, and intensive rehabilitation even in the end stage ambulatory patient, were factors in helping preserve function in these patients with dystrophinopathies.