Prefrontal Cortex and Supplementary Motor Area Activation During Robot-Assisted Weight-Supported Over-Ground Walking in Young Neurological Patients: A Pilot fNIRS Study

Abstract

Introduction: Rehabilitation therapy devices are designed for practicing intensively task-specific exercises inducing long-term neuroplastic changes underlying improved functional outcome. The Andago enables over-ground walking with bodyweight support requiring relatively high cognitive demands. In this study, we investigated whether we could identify children and adolescents with neurological gait impairments who show increased hemodynamic responses of the supplementary motor area (SMA) or prefrontal cortex (PFC) measured with functional near-infrared spectroscopy (fNIRS) when walking in Andago compared to walking on a treadmill. We further assessed the practicability and acceptability of fNIRS.Methods: Thirteen participants (two girls, 11 boys, age 8.0–15.7 years) with neurological impairments walked in the Andago and on a treadmill under comparable conditions. We measured hemodynamic responses over SMA and PFC during 10 walks (each lasting 20 s.) per condition and analyzed the data according to the latest recommendations. In addition, we listed technical issues, stopped the time needed to don fNIRS, and used a questionnaire to assess acceptability.Results: Hemodynamic responses varied largely between participants. Participants with a typical hemodynamic response (i.e., increased oxygenated hemoglobin concentration) showed large cortical activations during walking in Andago compared to treadmill walking (large effect sizes, i.e., for SMA: r = 0.91, n = 4; for PFC: r = 0.62, n = 3). Other participants showed atypical (SMA: n = 2; PFC: n = 4) or inconclusive hemodynamic responses (SMA: n = 5; PFC: n = 4). The median time for donning fNIRS was 28 min. The questionnaire indicated high acceptance of fNIRS, despite that single participants reported painful sensations.Discussion: Repetitive increased activation of cortical areas like the SMA and PFC might result in long-term neuroplastic changes underlying improved functional outcome. This cross-sectional pilot study provides first numbers on hemodynamic responses in SMA and PFC during walking in Andago in children with neurological impairments, reveals that only a small proportion of the participants shows typical hemodynamic responses, and reports that fNIRS requires considerable time for donning. This information is needed when designing future longitudinal studies to investigate whether increased brain activation of SMA and PFC during walking in Andago could serve as a biomarker to identify potential therapy responders among children and adolescents undergoing neurorehabilitation.

Neural correlates of fine motor grasping skills: Longitudinal insights into motor cortex activation using fNIRS

“…Hypothesis 1 changes in activation patterns hypothesis: Drawing from neuroimaging studies, it is hypothesized that during the early stages of motor learning, there will be a significant increase in activation in PFC and SMA. This is aligned with the finding, where early stages of motor skill acquisition were associated with increased activity in these regions (van Hedel et al., 2021). Conversely, in the later stages of learning, we anticipate a significant increase in activation in M1 and PL, as demonstrated by the posterior shift in cortical activation observed in studies (Krüger et al., 2020; Sun et al., 2022).…”

Benefits of a Wearable Cyborg HAL (Hybrid Assistive Limb) in Patients with Childhood-Onset Motor Disabilities: A 1-Year Follow-Up Study

“…Hubertus J.A. Van Hedel et al [ 40 , 45 ] reported the effects of gait training using a robotic device in young neurological patients with CP as well as CIP, hemiparesis, and demyelination. In addition, robot-assisted gait therapy is increasingly being used in pediatric neurorehabilitation for neurological gait disorders, including meningomyelocele (spina bifida) as well as CP, complementing conventional physical therapy [ 13 ].…”

Defining, quantifying, and reporting intensity, dose, and dosage of neurorehabilitative interventions focusing on motor outcomes

“…For example, Holper and colleagues ( 67 ) analyzed changes in the activation of the primary motor cortex (M1) using functional near-infrared spectroscopy (fNIRS) in healthy adults performing hand exercises of different complexity. We recently investigated whether the prefrontal cortex and the supplementary motor area showed increased activations when children with gait impairments walked in the over-ground bodyweight supporting device Andago compared to treadmill walking ( 68 ). Walking in the Andago appears closer to reality and requires more concentration than walking on a treadmill ( 69 ).…”

“…Both studies indicate that the more complex tasks resulted in increased levels of brain activation. However, fNIRS currently seems too complicated to apply clinically ( 68 ).…”