Neural Correlates of Age-Related Changes in Precise Grip Force Regulation: A Combined EEG-fNIRS Study

Abstract

Motor control is associated with suppression of oscillatory activity in alpha (8–12 Hz) and beta (12–30 Hz) ranges and elevation of oxygenated hemoglobin levels in motor-cortical areas. Aging leads to changes in oscillatory and hemodynamic brain activity and impairments in motor control. However, the relationship between age-related changes in motor control and brain activity is not yet fully understood. Therefore, this study aimed to investigate age-related and task-complexity-related changes in grip force control and the underlying oscillatory and hemodynamic activity. Sixteen younger [age (mean ± SD) = 25.4 ± 1.9, 20–30 years] and 16 older (age = 56.7 ± 4.7, 50–70 years) healthy men were asked to use a power grip to perform six trials each of easy and complex force tracking tasks (FTTs) with their right dominant hand in a randomized within-subject design. Grip force control was assessed using a sensor-based device. Brain activity in premotor and primary motor areas of both hemispheres was assessed by electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS). Older adults showed significantly higher inaccuracies and higher hemodynamic activity in both FTTs than did young adults. Correlations between grip force control owing to task complexity and beta activity were different in the contralateral premotor cortex (PMC) between younger and older adults. Collectively, these findings suggest that aging leads to impairment of grip force control and an increase in hemodynamic activity independent of task complexity. EEG beta oscillations may represent a task-specific neurophysiological marker for age-related decline in complex grip force control and its underlying compensation strategies. Further EEG-fNIRS studies are necessary to determine neurophysiological markers of dysfunctions underlying age-related motor disabilities for the improvement of individual diagnosis and therapeutic approaches.

Shedding light on neuroscience: Two decades of functional near‐infrared spectroscopy applications and advances from a bibliometric perspective

“…However, clustering co‐occurrences of words and how they relate provided the possibility to predict the newest tendencies and the future of fNIRS. For example, in the last year, authors dedicated their attention to cognitive functions and motor impairment, 56,58,122,123 development and language, 124–127 social and emotional engagement, 128–130 BCI systems, 63,64 and rehabilitation 131 …”

“…For example, in the last year, authors dedicated their attention to cognitive functions and motor impairment, 56,58,122,123 development and language, [124][125][126][127] social and emotional engagement, [128][129][130] BCI systems, 63,64 and rehabilitation. 131 This study has several limitations.…”

“…The prefrontal cortex plays a significant role in the cognitive control of movement 54 and is associated with gait disorders, especially in older adults. [55][56][57][58] Recently, scientific evidence based on hemodynamics suggested a consistent link between the prefrontal cortex and cortical-motor areas during motor tasks. 59,60 Combining fNIRS with fast time-resolution modalities, such as electrophysiological signals, it is possible to implement multimodal brain computer interface (BCI) systems capable of mapping motor functions, enhancing affected neural patterns, and detecting movement classification problems with significant accuracy.…”

“…Mobility impairment contributes the most to the loss of independence in daily activities. The prefrontal cortex plays a significant role in the cognitive control of movement 54 and is associated with gait disorders, especially in older adults 55–58 . Recently, scientific evidence based on hemodynamics suggested a consistent link between the prefrontal cortex and cortical‐motor areas during motor tasks 59,60 .…”

Older individuals do not show task specific variations in EEG band power and finger force coordination

“…It consistently indicates that, in general, individuals over the age of 60 tend to apply greater grip force than young adults [2]. Despite this general trend, EEG analysis demonstrated that the specific neural processes and cortical activations associated with grip force among the older population can vary depending on the task being performed [16,20]. This implies that the association between the grip force coordination and neural activity varies across different activities.…”