Brain Activation Changes While Walking in Adults with and without Neurological Disease: Systematic Review and Meta-Analysis of Functional Near-Infrared Spectroscopy Studies

Abstract

(1) Functional near-infrared spectroscopy (fNIRS) provides a useful tool for monitoring brain activation changes while walking in adults with neurological disorders. When combined with dual task walking paradigms, fNIRS allows for changes in brain activation to be monitored when individuals concurrently attend to multiple tasks. However, differences in dual task paradigms, baseline, and coverage of cortical areas, presents uncertainty in the interpretation of the overarching findings. (2) Methods: By conducting a systematic review of 35 studies and meta-analysis of 75 effect sizes from 17 studies on adults with or without neurological disorders, we show that the performance of obstacle walking, serial subtraction and letter generation tasks while walking result in significant increases in brain activation in the prefrontal cortex relative to standing or walking baselines. (3) Results: Overall, we find that letter generation tasks have the largest brain activation effect sizes relative to walking, and that significant differences between dual task and single task gait are seen in persons with multiple sclerosis and stroke. (4) Conclusions: Older adults with neurological disease generally showed increased brain activation suggesting use of more attentional resources during dual task walking, which could lead to increased fall risk and mobility impairments. PROSPERO ID: 235228.

Effect of Heart Rate Reserve on Prefrontal Cortical Activation While Dual-Task Walking in Older Adults

“…Consistent with prior work demonstrating increased PFC activation in older adults while dual-task walking [ 46 , 47 ], we observed PFC activation increases when going from a from an easier dual task to a more difficult dual task (neutral, congruent, and incongruent to switching walking tasks). Decreased accuracy rates were observed in both cohorts in incongruent and switching tasks, relative to neutral tasks, consistent with the increased difficulty observed during these more challenging conditions while walking [ 24 ].…”

Motor Cortical Activation Assessment in Progressive Multiple Sclerosis Patients Enrolled in Gait Rehabilitation: A Secondary Analysis of the RAGTIME Trial Assisted by Functional Near-Infrared Spectroscopy

“…Previous studies also observed increased levels of oxygenated hemoglobin and total hemoglobin in the medial primary sensorimotor cortices and the supplementary motor areas during walking [38], and during walking and balance tasks, in older adults-both among patients with Parkinson's disease [40] and among stroke patients [41]. Among PwMS, increased cortical activity was reported during a dual task that included walking [25,42,43], but the opposite was observed during a finger-tapping motor task [44].…”

“…This non-invasive technique-which measures cortical oxygenation and, consequently, cortical activation through near-infrared light and does not expose the patient to ionizing radiation-may represent a useful tool in neurorehabilitation [22,23], allowing measurements to be taken during different tasks across various neurological disorders [17]. In PwMS, this promising technique has mainly been exploited using frontal measurements and cross-sectional studies [17,24,25], while any relationships with the outcome measures or the effects of rehabilitation have gone unobserved [17,[20][21][22]26]. Increased activation of motor and premotor cortical areas has been found in stroke patients during treadmill walking [27] and in healthy subjects during different walking modalities [28], whereas in PwMS, only the role of the prefrontal cortex during walking has been assessed [17].…”

Motoric cognitive risk syndrome in people with multiple sclerosis: prevalence and correlations with disease-related factors

“…motor planning and coordination, were found both in elders with MCR 33 and pwMS. 39 Finally, the neural mechanism might be explained by the abnormalities in the inflammatory cytokine system. For example, the expression of interleukin (IL)-10 was found associated with an increased incidence of MCR in elders, 40 and associated with low results on cognition tests in relapsing-remitting MS patients.…”