Background: Repeated soccer heading may induce neurophysiological brain changes. While structural alterations have been observed, functional impairments remain debated.
Objective: This study systematically examines the acute and long-term neurophysiological effects of heading using EEG.
Methods: A systematic review following PRISMA guidelines included studies assessing EEG changes after heading. Literature searches were conducted in PubMed, Cochrane, SportDiscus, and Embase until January 2025. Study quality was evaluated using RoB 2, ROBINS-I, JBI, and the Newcastle-Ottawa Scale.
Results: Ten studies met the criteria. Acute effects included increased delta activity in frontal, central, and parietal regions, normalizing within seconds. Long-term changes involved reduced P3a/P3b amplitudes, altered theta and beta activity, and impairments in attention, memory, and reaction time. A dose-dependent relationship was observed, but methodological heterogeneity limits comparability.
Conclusion: Soccer heading may cause neurophysiological effects, particularly affecting cognitive functions. Standardized EEG protocols and longitudinal studies are needed to clarify causal relationships.
Table of Contents
1 Introduction
2 Materials and Methods
2.1 Search Strategy
2.2 Study selection
2.3 Data extraction and quality assessment
3 Results
3.1 Characteristics of the selected studies
3.2 EEG-Acquisition
3.3 Quality assessment
3.4 Acute effect of Heading on neuroelectricity
3.5 Chronic effect of Heading on neuroelectricity
3.6 Cognitive Tests
3.7 Symptoms
4 Discussion
4.1 Acute effect of Heading on neuroelectricity and cognition
4.2 Chronic effect of Heading on neuroelectricity and cognition
4.3 Symptoms
5 Conclusion
Objectives and Topics
The primary objective of this systematic review is to evaluate the acute and chronic neurophysiological effects of repetitive soccer heading using electroencephalographic (EEG) measurements. By systematically examining existing empirical literature, the work seeks to clarify whether repetitive, sub-concussive head impacts lead to measurable alterations in neural activity and whether these electrophysiological changes correlate with objective neurocognitive impairments and clinical symptom profiles.
- Electroencephalographic analysis of acute, short-term, and chronic alterations in brain wave frequency bands (delta, theta, alpha, beta) and event-related potentials.
- Evaluation of sub-concussive mechanical head impacts in association football and their distinction from clinical concussions or mild traumatic brain injury.
- Assessment of neurocognitive functions, with an emphasis on attention, working memory, executive function, and psychomotor reaction speed.
- Identification of reported post-impact symptoms, including headache, intracranial pressure sensation, fatigue, and cognitive complaints.
- Methodological critique of existing observational and experimental heading protocols, risk of bias, and confounding lifestyle and athletic factors.
Excerpt from the Book
1 Introduction
Head injuries in soccer have become an increasingly relevant research topic, particularly concerning the long-term neurological consequences of repeated heading. While most head injuries in soccer result from collisions with other players (Pickett, 2005), heading represents a unique and recurrent mechanical load on the brain. Players perform an average of 1 to 16 headers per match (Kontos et al., 2011), accumulating to several thousand headers over the course of a career. Although concussions—a form of mild traumatic brain injury (mTBI) that does not present structural abnormalities in CT or MRI scans—account for only 1–5% of all soccer-related injuries (Boden et al., 1998; Marar et al., 2012; Junge et al., 2012), the potential long-term effects of repeated non-concussive impacts on brain function remain unresolved.
Non-concussive impacts—head traumas that do not produce clinically detectable symptoms (sub-clinical)—are gaining increasing attention in research (Eliason et al., 2023). It is debated whether repeated headers may have adverse effects on the brain similar to those observed in combat sports such as boxing (Spiotta et al., 2012). Recent studies suggest that non-concussive, yet repetitive head impacts may be associated with an increased risk of neurodegenerative diseases later in life (Mackay et al., 2019; Ueda et al., 2023). Several systematic reviews have already examined structural brain alterations resulting from heading (Tarnutzer et al., 2016; Koerte et al., 2023). Neuroimaging studies indicate that repeated non-concussive impacts can affect both brain structure and function (Abbas et al., 2015; Chun et al., 2015; Belanger et al., 2014;). However, the current body of evidence remains inconsistent, as some studies have failed to detect significant changes (Tarnutzer et al., 2016).
A major challenge in researching the effects of heading is the selection of appropriate assessment methods. While imaging techniques such as magnetic resonance imaging (MRI) can detect structural brain changes, electroencephalography (EEG) is particularly well suited for examining functional alterations in brain activity. Initial systematic reviews on EEG alterations following heading suggest potential functional impairments, yet they exhibit methodological limitations (Tarnutzer et al., 2017; Ntikas et al., 2022). EEG measurements have demonstrated that individuals diagnosed with concussion exhibit abnormal brain activity, even when clinical test results appear unremarkable (Tarnutzer et al., 2017). Furthermore, there is evidence suggesting that even a short period of repeated heading may induce both functional and structural changes (Di Virgilio et al., 2016; Ashton et al., 2021).
Chapter Summaries
1 Introduction: Outlines the problem of repetitive sub-concussive head impacts in association football, reviewing existing structural and functional literature while justifying the need for an EEG-based systematic review.
2 Materials and Methods: Delineates the PRISMA-compliant literature search strategy across electronic databases, study inclusion and exclusion criteria, data extraction processes, and quality assessment instruments.
3 Results: Presents the synthesized empirical data from ten included studies, summarizing participant demographics, recording settings, acute and chronic frequency band perturbations, cognitive testing performance, and post-heading symptoms.
4 Discussion: Evaluates the neuroelectric findings within the context of mechanical strain and cognitive control, critically analyzing methodological limitations, confounding variables, and differences between virtual training paradigms and actual heading impacts.
5 Conclusion: Summarizes the key insights confirming heading-induced electrophysiological and cognitive alterations, while highlighting critical methodological requirements for future prospective longitudinal investigations.
Keywords
Soccer, Heading, Electroencephalography, EEG, Neurophysiology, Sub-concussive Impacts, Cognitive Impairment, Delta Power, Theta Activity, Event-Related Potentials, Mild Traumatic Brain Injury, Systematic Review
Frequently Asked Questions
What is the primary scope of this work?
The work provides a comprehensive systematic review investigating the immediate and cumulative neurophysiological consequences of intentional soccer heading through electroencephalographic (EEG) analysis.
What are the central thematic areas examined in the study?
The core areas include acute and chronic changes in brain wave spectra, event-related potentials, neurocognitive performance metrics (such as attention and reaction speed), and clinical symptoms following sub-concussive impacts.
What is the primary objective and research question?
The main objective is to clarify whether repetitive sub-concussive ball impacts to the head cause measurable functional brain alterations and adverse cognitive outcomes in soccer players across different competitive levels and age groups.
Which scientific methodology was utilized?
The author conducted a systematic review following PRISMA guidelines, executing structured database searches in PubMed, Cochrane, SportDiscus, and Embase, alongside rigorous methodological quality appraisals using RoB 2, ROBINS-I, JBI appraisal tools, and the Newcastle-Ottawa Scale.
What is discussed in the main results section?
The results synthesize findings from ten studies, reporting acute increases in delta power that normalize rapidly, chronic elevations in theta activity and reductions in P3 amplitudes, prolonged reaction times, attention deficits, and symptoms such as post-heading headaches.
Which keywords best characterize this research?
The publication is characterized by soccer, heading, electroencephalography (EEG), neurophysiology, sub-concussive impacts, event-related potentials, cognitive impairment, and systematic review.
What specific acute EEG perturbations are observed immediately after heading a soccer ball?
Controlled experimental studies demonstrated a significant surge in delta power in frontal, central, and parietal brain regions within 0.3 to 1.3 seconds following impact, with stronger elevations occurring after higher-intensity impacts and showing contralateral hemisphere specificity for oblique headers before normalizing within seconds.
How do chronic heading exposure and repeated sub-concussive impacts influence cognitive testing?
Chronic exposure is associated with impaired visual attention, prolonged simple and choice reaction times, and increased error rates in working memory tasks, frequently correlating with reduced P3a/P3b amplitudes and left temporal theta dysrhythmias.
Why did virtual reality heading yield different neurophysiological outcomes compared to actual ball heading?
Virtual reality heading stimulated active cortical reorganization and motor anticipation reflected by enhanced frontal theta, alpha, and beta activity without physical strain, whereas actual ball contact triggered acute physiological stress responses and immediate biomechanical disruption without compensatory cognitive enhancements.
- Quote paper
- Vincent Ermisch (Author), 2024, Neurophysiological Responses to Heading in Soccer. A Systematic Review of EEG-Based Analysis, Munich, GRIN Verlag, https://www.grin.com/document/1768432
