Long-term working memory deficits after concussion: electrophysiological evidence

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurophysiology

Background:

• Persistent memory and concentration issues are common after concussion, with unknown brain origins.
• The P300 event-related potential (ERP) component, measured via electroencephalography (EEG), is a potential biomarker for these subtle cognitive impairments.

Purpose of the Study:

• To investigate P300 and cognitive performance in individuals with remote concussions.
• To assess the impact of varying working memory load using an n-back task on P300 and performance.

Main Methods:

• A visual n-back task was administered to 17 participants with remote concussions and 17 controls.
• Working memory load was manipulated to systematically increase cognitive demands.
• Neuropsychological and self-report measures were also collected.

Main Results:

• The concussion group exhibited significantly lower P300 amplitude compared to controls, irrespective of working memory load.
• No significant differences in n-back task performance were found between the groups.
• A negative correlation between P300 amplitude and response times was observed at higher cognitive loads in both groups.

Conclusions:

• Individuals with remote concussions may display inefficient neural resource recruitment for target identification, evidenced by an attenuated P300.
• The findings suggest that reduced P300 amplitude correlates with increased response times under high working memory demands, indicating impaired cognitive processing efficiency post-concussion.