Sub-acute stroke demonstrates altered beta oscillation and connectivity pattern in working memory

 

Big fucking whoopee.

 

 But you tell us NOTHING ABOUT A SOLUTION Useless!

Sub-acute stroke demonstrates altered beta oscillation and connectivity pattern in working memory

• Lin Mao,
• Xianwei Che,
• Juehan Wang,
• Xiaorui Jiang,
• Yifan Zhao,
• Liliang Zou,
• Shuang Wei,
• Shuyi Pan,
• Dazhi Guo,
• Xueqiong Zhu,
• Dongxia Hu,
• Xiaofeng Yang,
• Zuobing Chen &
• Daming Wang 

Journal of NeuroEngineering and Rehabilitation volume 21, Article number: 212 (2024) Cite this article

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Abstract

Introduction

Working memory (WM) is suggested to play a pivotal role in relearning and neural restoration during stroke rehabilitation. Using EEG, this study investigated the oscillatory mechanisms of WM in subacute stroke.

Methods

This study included 48 first subacute stroke patients (26 good-recovery, 22 poor-recovery, based on prognosis after a 4-week period) and 24 matched health controls. We examined the oscillatory characteristics and functional connectivity of the 0-back WM paradigm and assessed their associations with prognosis.

Results

Patients of poor recovery are characterised by a loss of significant beta rebound, beta-band connectivity, as well as impaired working memory speed and performances. Meanwhile, patients with good recovery have preserved these capacities to some extent. Our data further identified beta rebound to be closely associated with working memory speed and performances.

Conclusions

We provided novel findings that beta rebound and network connectivity as mechanistic evidence of impaired working memory in subacute stroke. These oscillatory features could potentially serve as a biomarker for brain stimulation technologies in stroke recovery.

Introduction

Stroke is the third most common cause of morbidity and the second most common cause of dementia [1]. The most common symptoms of stroke include physical deficits (such as paralysis, and sensory loss) and dysfunction in learning, memory, and executive functions. When it comes to cognitive function, working memory (WM) has a fundamental role in performing complex behaviours and is associated with poor functional outcomes after a stroke [2, 3].

An abrupt, cliff-like decline in brain function represents a key difference between acute stroke and neurodegenerative cerebral disorders. More importantly, this pattern of cognitive decline exhibits reversibility within a defined temporal framework [4], which is critical for both neural restoration and clinical rehabilitation. In clinical practices, there is also evidence supporting the ability to regain partial functions or develop compensatory skills through the process of learning [5]. Notably, working memory underpins the learning processes [2], making it critical for neural restoration and clinical rehabilitation. It is therefore important to investigate the behavioural and neural dynamics of WM, offering insights for the development of more effective rehabilitation strategies.(WHOM SPECIFICALLY DID YOU CONTACT TO GET THAT RESEARCH DONE? NO ONE? So, you're a complete failure at doing your job?)

Working memory is defined as a multi-component system involved in goal-directed behaviours that involve retaining and manipulating information [6]. N-back task is a well-validated and widely used means of manipulating working memory capacity and its response requirements [7]. Among them, 0-back requires less workload, which is highly suitable for post-stroke individuals with significant cognitive impairment. It includes components such as sustained attention to a stimulus and continuous memory of the instructions. It is noted that clinical assessment of vascular cognitive impairment (VCI) predominantly relies on cognitive scales, with a paucity of concurrent evidence from cognitive tasks such as WM.

Using an electroencephalogram (EEG), previous studies have established the oscillatory mechanisms of WM. Most of the studies have identified increased power in the fast oscillatory ranges such as beta (13–30 Hz) and gamma (30–100 Hz) [8, 9]. In terms of the functioning, gamma oscillation is suggested to store memories, while beta oscillation is closely associated with attention and response selection [9,10,11]. However, the effects of stroke on neural oscillations underlying WM are largely unclear. A recent scoping review indicated a correlation between decreased fast waves (such as beta) and poor cognition following a stroke [12].

This study was designed to investigate the oscillatory characteristics of working memory in subacute stroke patients. Patients in the subacute stroke underwent a visual-spatial WM 0-back with EEG recordings. They were further classified as good-recovery (n = 26) and poor-recovery (n = 22) according to the modified Rankin Score (mRS). We hypothesized that stroke patients would demonstrate lower power in beta and gamma range compared to healthy controls. Moreover, patients with a poor recovery would have a more prominent decrease in beta and gamma oscillation.

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