Individuals with Chronic Mild-to-Moderate Traumatic Brain Injury Exhibit Decreased Neuromuscular Complexity During Gait

Abstract

Background Synergy analysis provides a means of quantifying the complexity of neuromuscular control during gait. Prior studies have shown evidence of reduced neuromuscular complexity during gait in individuals with neurological disorders associated with stroke, cerebral palsy, and Parkinson’s disease. Objective The purpose of this study was to investigate neuromuscular complexity during gait in individuals who experienced a prior traumatic brain injury (TBI) that resulted in chronic balance deficits. Methods We measured and analyzed lower extremity electromyographic data during treadmill and overground walking for 44 individuals with residual balance deficits from a mild-to-moderate TBI at least 1 year prior. We also tested 20 unimpaired controls as a comparison. Muscle synergies were calculated for each limb using non-negative matrix factorization of the activation patterns for 6 leg muscles. We quantified neuromuscular complexity using Walk-DMC, a normalized metric of the total variance accounted for by a single synergy, in which a Walk-DMC score of 100 represents normal variance accounted for. We compared group average synergy structures and inter-limb similarity using cosine similarity. We also quantified each individual’s gait and balance using the Sensory Organization Test, the Dynamic Gait Index, and the Six-Minute Walk Test. Results Neuromuscular complexity was diminished for individuals with a prior TBI. Walk-DMC averaged 92.8 ± 12.3 for the TBI group during overground walking, which was significantly less than seen in controls (100.0 ± 10.0). Individuals with a prior TBI exhibited 13% slower overground walking speeds than controls and reduced performance on the Dynamic Gait Index (18.5 ± 4.7 out of 24). However, Walk-DMC measures were insufficient to stratify variations in assessments of gait and balance performance. Group average synergy structures were similar between groups, although there were considerable between-group differences in the inter-limb similarity of the synergy activation vectors. Conclusions Individuals with gait and balance deficits due to a prior TBI exhibit evidence of decreased neuromuscular complexity during gait. Our results suggest that individuals with TBI exhibit similar muscle synergy weightings as controls, but altered control of the temporal activation of these muscle weightings.

The Effect of Dual-Task Motor-Cognitive Training in Adults with Neurological Diseases Who Are at Risk of Falling

“…Third, as recently shown by Acuña et al [ 35 ], individuals who have experienced a prior TBI exhibit a decrease in neuromuscular complexity during gait. These data contribute to a growing body of evidence which suggests that brain injury reduces the complexity of the muscle activation patterns that underlie gait, and hence, may be due to a change in the use of cortical activity to modulate the rhythmic muscle activation patterns that underlie walking [ 35 , 37 , 38 ].…”

“…Second, the gait and balance deficits that characterise individuals with TBI vary considerably in terms of presentation pathophysiology [ 34 ] and severity [ 35 , 36 ]. This results in substantial variability in walking patterns among subjects, which may interfere with the average walking performance improvement.…”

Adaptation of the Lower Extremity Neuromuscular Activation While Performing the Ross Submaximal Cardiovascular Test in Healthy Adults

“…Some researchers propose there is no definite activation pattern during normal gait in healthy adults, based on findings from Di Nardo et al (2013), who indicated different activation intervals and activities throughout the phases of gait, which are usually not reported in healthy adults. In a different population, Acuña et al (2022) revealed the effects of traumatic brain injury on muscle recruitment and that TA, and the medial head of the gastrocnemius revealed impaired muscle activation. Subsequently, it showed impairment in the dynamic gait index, with an average of 19 +/± 5.45%, correlating with an increased fall risk.…”

Effectiveness of cerebellar vermis intermittent theta-burst stimulation in improving trunk control and balance function for patients with subacute stroke: a randomised controlled trial protocol

“…The composite equilibrium score of the SOT characterises the impairments of individual sensory systems. 53 The ability to voluntarily move the COG within the LOS is fundamental to mobility tasks. By the LOS test, reaction time, movement velocities and excursions are recorded to measure the voluntary ability to shift the COG without losing balance.…”