Near-Infrared Spectroscopy in Gait Disorders: Is It Time to Begin?

Abstract

Walking is a complex motor behavior with a special relevance in clinical neurology. Many neurological diseases, such as Parkinson's disease and stroke, are characterized by gait disorders whose neurofunctional correlates are poorly investigated. Indeed, the analysis of real walking with the standard neuroimaging techniques poses strong challenges, and only a few studies on motor imagery or walking observation have been performed so far. Functional near-infrared spectroscopy (fNIRS) is becoming an important research tool to assess functional activity in neurological populations or for special tasks, such as walking, because it allows investigating brain hemodynamic activity in an ecological setting, without strong immobility constraints. A systematic review following PRISMA guidelines was conducted on the fNIRS-based examination of gait disorders. Twelve of the initial yield of 489 articles have been included in this review. The lesson learnt from these studies suggest that oxy-hemoglobin levels within the prefrontal and premotor cortices are more sensitive to compensation strategies reflecting postural control and restoration of gait disorders. Although this field of study is in its relative infancy, the evidence provided encourages the translation of fNIRS in clinical practice, as it offers a unique opportunity to explore in depth the activity of the cortical motor system during real walking in neurological patients. We also discuss to what extent fNIRS may be applied for assessing the effectiveness of rehabilitation programs.

Functional Near-Infrared Spectroscopy to Study Cerebral Hemodynamics in Older Adults During Cognitive and Motor Tasks: A Review

“…Emerging alternatives to fMRI, based on near-infrared diffuse optical techniques, allow measurements in more realistic environments and during motion (Boas et al, 2014;Scholkmann et al, 2014). Accumulating evidence supports the use of these techniques for the study of frontal hemodynamic and metabolic changes (Agbangla et al, 2017;Gramigna et al, 2017). These diffuse optical techniques such as fNIRS (Durduran et al, 2010;Ferrari and Quaresima, 2012) allow the study of tissue composition by emitting near-infrared light (∼650-950 nm) into biological tissue and collecting the photons that undergo multiple scattering and absorption (i.e., diffuse) and emerge few centimeters away from the injection point (Delpy and Cope, 1997;Durduran et al, 2010).…”

“…However, these findings are still preliminary and it is not yet clear if there is a specific pattern according to age or cognitive status, nor about how these differences should be interpreted. Recently published reviews have assessed the results of studies on fNIRS during cognitive tasks (Herold et al, 2018) or dual tasks (Gramigna et al, 2017;Herold et al, 2017;Leone et al, 2017;Vitorio et al, 2017;Stuart et al, 2018;Kahya et al, 2019) and some of them have chosen to focus on specific clinical profiles (Gramigna et al, 2017;Vitorio et al, 2017) or on methodological aspects such as fNIRS signal processing (Herold et al, 2017(Herold et al, , 2018Vitorio et al, 2017). To the best of our knowledge, our review is the first to focus specifically on older adults regardless of their clinical profile and to assess, from a clinical point of view, studies using only cognitive or motor tasks, as well as DTs.…”

Inter-Session Reliability of Functional Near-Infrared Spectroscopy at the Prefrontal Cortex While Walking in Multiple Sclerosis

“…Functional near-infrared spectroscopy (fNIRS) is a promising tool that provides the following properties [7]. It is a non-invasive, easy to apply, and portable optical brain imaging method that is applicable in motion [8][9][10]. It is less affected by motion artefacts than comparable systems and has a relatively high temporal resolution up to 1 ms [8,11].…”

Passive, yet not inactive: robotic exoskeleton walking increases cortical activation dependent on task

“…As many neurological conditions are associated with gait disorders, examining brain activation associated with gait and/or gait interventions are recommended with fNIRS [63,64]. Passive movements are used in neurorehabilitation to maintain or improve mobility and range of motion, as well as to have individuals experience sensorimotor aspects of mobility that may be outside of their current abilities.…”