Prefrontal activation during dual-task seated stepping and walking performed by subacute stroke patients with hemiplegia

They say nothing about what objective damage diagnosis this would be good to implement for. So from my perspective, useless.

Prefrontal activation during dual-task seated stepping and walking performed by subacute stroke patients with hemiplegia

Shinnosuke Nosaka^1,2, Ken Imada², Kazuya Saita¹ and Hitoshi Okamura^1*

• ¹Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
• ²Kinkai Rehabilitation Hospital, Yonago, Japan

Objectives: This study examined prefrontal cortex (PFC) activation during dual-task seated stepping and walking performed by subacute stroke patients with hemiplegia and evaluated the relationship between PFC activation, frontal lobe functions, and dual-task interference.

Methods: Patients with functional ambulation category (FAC) scores ≤ 2 comprised the seated stepping task group. Those with FAC scores > 2 comprised the walking task group. There were 11 patients in the seated stepping task group (mean age, 65.3±12.2 years; age range, 55-73.5 years; 7 male and 4 female patients; time since stroke onset, 45.7±9.9 days) and 11 patients in the walking task group (mean age, 65.6±15.2 years; age range, 49.5-74.5 years; 7 male and 4 female patients; time since stroke onset, 57.5±18.3 days). Both groups completed the Frontal Assessment Battery (FAB). The seated stepping task group performed the following three tasks: cognitive task (CT), normal seated stepping (NSS), and dual-task seated stepping (DTSS). The walking task group completed the following tasks: CT, normal walking (NW), and dual-task walking (DTW). The CT was a letter fluency task; this letter fluency task was simultaneously performed during seated stepping (DTSS) and walking (DTW). Changes in the oxygenated hemoglobin (O₂Hb) concentration and deoxygenated hemoglobin concentration during the tasks were measured using near-infrared spectroscopy (Pocket NIRS HM; Dynasense Inc., Japan). The number of steps, walking speed, and percentage of correct responses to the CT were recorded.

Results: The results showed that DTSS activated the PFC significantly more than performing a single task and that NSS was associated with a significantly higher difference in the hemoglobin concentration when compared to that associated with the CT, which was a single task. In the walking task group, PFC activation was significantly higher during DTW, NW, and CT (in that order), and O₂Hb concentrations were significantly higher in the contralesional hemisphere than in the ipsilesional hemisphere during all tasks. Associations between PFC activation, FAB scores, and dual-task interference in the seated task group indicated significant positive correlations between FAB scores and cognitive performance with dual-task interference.

Conclusion: DTSS may be an effective means of activating the PFC of patients with difficulty walking.

1. Introduction

When performing dual tasks (motor and cognitive tasks (CTs) performed simultaneously), stroke patients exhibit significantly poorer performance than healthy older adults (Plummer et al., 2013). It has been reported that dual tasks activate the prefrontal cortex (PFC; Yogev-Seligmann et al., 2008). Dual-task training for stroke patients has been shown to effectively improve dual-task gait function and decrease the incidence of falls (Pang et al., 2018). Within the PFC, the frontal pole is involved in cognitive processes that lead to voluntary behavior (Zysset et al., 2002; Haggard, 2008). The frontal pole is also preferentially activated when learning new motor tasks (Ishikuro et al., 2014) and has an important role in rehabilitation.

Functional near-infrared spectroscopy (fNIRS) has been used in several studies of PFC activity, especially during walking, because it offers a greater degree of freedom when performing measurements and allows for real-time measurements (Pelicioni et al., 2019; Lim et al., 2022). Furthermore, among fNIRS instruments, wireless devices allow measurements not only while walking on a treadmill but also while walking at comfortable speeds in natural environments (Nosaka et al., 2022). The fNIRS studies that have evaluated changes in the oxygenated hemoglobin (O₂Hb) concentrations of stroke patients reported greater changes in the PFC during dual tasks than during the performance of a single task (Al-Yahya et al., 2016; Hawkins et al., 2018; Liu et al., 2018). Furthermore, patients with poor motor function rely more on the cortical control of gait (Miyai et al., 2002), and PFC activation in stroke patients is correlated with physical performance (Mori et al., 2018).

Studies involving subacute stroke patients have shown an upper limit of PFC oxygenation during walking alone (Hermand et al., 2019); however, few studies of subacute stroke patients have been performed. Many subacute stroke patients undergoing the process of functional recovery have difficulty walking. Seated stepping is easy to perform, even for patients with difficulty walking, because of the low risk of falling, and dual-task seated stepping (DTSS) activates the PFC (Ohsugi et al., 2013). A randomized controlled trial that introduced stepping as an exercise showed that DTSS effectively improved gait performance compared to stepping alone (Yamada et al., 2012). However, these studies involved healthy older subjects living in the community. There are no reports of PFC activation during seated stepping tasks performed by stroke patients.

The main objective of this study was to examine PFC activation during DTSS and dual-task walking (DTW) performed by subacute stroke patients with hemiplegia. The secondary objective was to evaluate the association between PFC activation, frontal lobe functions, and dual-task interference. It was hypothesized that patients with poorer motor function would experience increased PFC activation during DTSS as well as during DTW. It was also hypothesized that there would be an association between PFC activation, frontal lobe functions, and dual-task interference. If the PFC is activated by seated stepping while performing a CT as well as by walking while performing a CT, then exercises for the rehabilitation of stroke patients who have difficulty walking could be optimized.

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