Effects of Functional Electrical Stimulation on Attention and Brain Activity in Healthy Participants Using Near-Infrared Spectroscopy: An Interventional Study

Nao Yoshihiro; Kazu Amimoto; Shinpei Osaki; Junpei Tanabe; Katsuya Sakai; Yumi Ikeda

doi:10.7759/cureus.57886

Effects of Functional Electrical Stimulation on Attention and Brain Activity in Healthy Participants Using Near-Infrared Spectroscopy: An Interventional Study

Cureus. 2024 Apr 9;16(4):e57886. doi: 10.7759/cureus.57886. eCollection 2024 Apr.

Authors

Nao Yoshihiro^{1

2}, Kazu Amimoto³, Shinpei Osaki⁴, Junpei Tanabe⁵, Katsuya Sakai², Yumi Ikeda²

Affiliations

¹ Department of Occupational Therapy, Kansai University of Health Sciences, Osaka, JPN.
² Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, JPN.
³ Department of Physical Therapy, Sendai Seiyo Gakuin College, Miyagi, JPN.
⁴ Department of Rehabilitation, Kansai Electric Power Hospital, Osaka, JPN.
⁵ Department of Physical Therapy, Hiroshima Cosmopolitan University, Hiroshima, JPN.

Abstract

Background Involuntary limb activation using functional electrical stimulation (FES) can improve unilateral spatial neglect. However, the impact of FES on brain activity related to spatial attention remains unclear. Thus, in this study, we aimed to examine the effects of FES on spatial attention. Methodology In this interventional study, 13 healthy right-handed participants were asked to perform the Posner task for six minutes both before and after either FES or sham stimulation during each set, resulting in a total of two sets. FES was applied to the left forearm extensor muscles, with a frequency of 25 Hz, a pulse width of 100 μs, and the intensity adjusted to reach the motor threshold. Both the energization and pause times were set to five seconds. The Posner task was used to measure reaction time to a target appearing on a computer screen. Brain activity, indicated by oxygenated hemoglobin values, was measured using near-infrared spectroscopy with 24 probes according to the International 10-20 system method. Results In the left hemisphere, oxygenated hemoglobin values in the premotor and supplementary motor areas, primary somatosensory cortex, and somatosensory association areas were significantly higher after FES than after sham stimulation. In the right hemisphere, oxygenated hemoglobin values were significantly increased in the premotor, primary, and supplementary motor areas; in the supramarginal gyrus; and in the somatosensory association areas after FES. Reaction times in the Posner task did not differ significantly between the FES and sham conditions. Conclusions Collectively, these results suggest that FES of the upper limbs can activate the ventral pathway of the visual attention network and improve stimulus-driven attention. Activation of stimulus-driven attentional function could potentially contribute to symptom improvement in patients with unilateral spatial neglect.

Keywords: functional electrical stimulation; functional near-infrared spectroscopy; posner task; reaction time; spatial attention.

Grants and funding

This research was funded by Grant-in-Aid for Young Scientists (grant number: JP20K19328) from the Japan Society for the Promotion of Science.