What Affects Balance and Brain Function: From Head Impact to Instability

How Concussion Disrupt These Systems

The force from a concussion often causes the brain to accelerate and decelerate within the skull. This movement can stretch and shear axons, disrupt blood flow, and alter neurotransmitter activity in regions responsible for balance and spatial awareness. Studies using diffusion tensor imaging (DTI) have shown that even mild traumatic brain injuries (mTBIs) can result in microstructural changes in white matter tracts that connect these regions, particularly the cerebellar peduncles and vestibular pathways (source).

Moreover, post-traumatic dizziness is one of the most common symptoms following concussion. Research estimates suggest that vestibular or balance issues are present in up to 85% of individuals evaluated in specialty concussion clinics (source). This can present as balance impairment, nausea, difficulty with quick head turns, or a sensation of motion intolerance.

The Vestibular System: Gatekeeper of Equilibrium

When the vestibular system is injured—whether through direct impact or secondary inflammation—it loses its ability to accurately convey spatial information to the brain. This miscommunication can create sensory conflict between what the eyes see, what the inner ear detects, and what the muscles feel. The result is imbalance and disorientation.

Vestibulo-ocular reflex (VOR) testing, dynamic visual acuity assessments, and balance testing are commonly used to detect these deficits. Tools like the Sway Balance test offer a practical advantage in these cases, especially in non-specialist settings. By quantifying postural sway through mobile devices, clinicians can assess whether the vestibular system is properly integrated into postural control—offering a window into functional recovery.

Other Contributing Factors to Balance Dysfunction

While the vestibular system is a critical player, it’s not the only factor affecting post-injury balance. Consider the following:

• Proprioceptive disruption: Concussions can impair the body's ability to sense joint position, particularly in the lower limbs. This is especially relevant in athletic populations where proprioceptive feedback is essential for safe movement.
  
  
• Visual disturbances: Up to 69% of concussion patients report some form of vision problem (source). Blurred vision, eye tracking difficulties, and photophobia all contribute to spatial disorientation and balance instability.
  
  
• Cognitive load: Dual-task testing (e.g., walking while performing a mental task) has revealed that concussed individuals often struggle more than controls. This suggests that balance isn’t purely physical—it’s also cognitive. The brain’s limited capacity for processing can become evident when it’s asked to multitask under stress.
  
  
• Autonomic nervous system dysfunction: Some patients develop dysregulation of heart rate and blood pressure post-concussion, leading to symptoms like lightheadedness or fainting when transitioning from lying to standing. This condition, known as orthostatic intolerance, further compounds balance issues.
  

Real-World Impact and Clinical Scenarios

Imagine a collegiate soccer player who takes a head-to-head hit during a match. They feel “off” but pass the sideline cognitive assessment. Later, when asked to perform a tandem stance or foam-based balance test using Sway’s mobile platform, they score significantly lower than baseline. This discrepancy flags vestibular impairment not caught by symptom checklists alone—allowing the athletic trainer to initiate early vestibular rehab and delay return-to-play until stability returns.

Or consider an older adult recovering from a minor fall who complains of feeling dizzy while walking. Traditional CT scans may show no structural damage, but balance testing highlights persistent instability. Recognizing these subtle deficits allows for targeted intervention, potentially preventing further injury from subsequent falls.

Rehabilitation: Addressing the Root, Not Just the Symptoms

Effective rehabilitation for balance dysfunction post-concussion must address all contributing systems. This often involves:

• Vestibular rehabilitation therapy (VRT): Customized exercises to retrain the brain’s interpretation of inner ear signals.
  
  
• Proprioceptive training: Tasks like balance boards or uneven surfaces to re-engage somatosensory input.
  
  
• Vision therapy: Supervised exercises to improve ocular tracking and visual-motor integration.
  
  
• Gradual cognitive reintegration: Layering in mental tasks during movement to mimic real-world complexity.
  
  

Outcome measures are essential throughout this process—not only to guide therapy but to ensure readiness for return to sport, school, or work. 

Balance is far more than standing still without swaying—it’s a coordinated dance between the brain, inner ear, vision, and muscle memory. When a concussion occurs, this harmony can be disrupted in subtle but significant ways. Understanding the many influences on balance and brain function after a head impact is key to providing comprehensive care.

Reliable, research-backed tools such as the Sway Balance test empower clinicians and athletic trainers to detect hidden impairments and tailor rehabilitation accordingly. As we continue to refine our understanding of concussion and recovery, one truth remains clear: early identification and targeted treatment of balance dysfunction can profoundly influence outcomes—and restore confidence along with stability.