Post Concussion Syndrome (PCS) is a complex disorder in which various common concussion symptoms — such as headaches, dizziness, and cognitive dysfunction — persist for weeks, months, or even years after the initial head trauma that caused the concussion. Research has shown that metabolic recovery after a concussion typically occurs between 22 and 45 days (Vagnozzi et al., 2010). However, not all concussed individuals recover that quickly. Approximately 30% of individuals who have sustained a mild traumatic brain injury will continue to experience persistent symptoms beyond the normal metabolic healing time (Ewing et al., 2018).

Why do symptoms persist in some patients following a head injury? Many mechanisms can lead to prolonged concussion recovery; this article will discuss the role of the visual and vestibular systems.

Understanding Post Concussion Syndrome.

Definition of Post Concussion Syndrome.

The 2022 Amsterdam Consensus Statement refers to PCS as persistent concussion symptoms beyond 30 days (4 weeks) in adults and children. The ICD-10 further defines PCS as the presence of three or more symptoms persisting more than 3 weeks following head trauma, while the DSM states that symptoms must persist beyond 3 months. 

The long-term effects of PCS can significantly impair an individual’s daily functioning and quality of life. These effects might include prolonged cognitive impairment and ongoing physical challenges due to balance, dizziness, or coordination issues. Additionally, individuals with PCS often experience barriers to returning to work, school, sports, or social activities.

The Vestibular System and Concussion.

What is the Vestibular System?

The vestibular system is located within the inner ear. This complex sensory system sends signals to the brain about the body’s motion and orientation in space, which is crucial in maintaining upright balance and visual stability. When functioning properly, the vestibular system allows us to walk, run, and move easily.

The vestibular system works with the visual system and proprioceptive feedback from muscles and joints to ensure sensory information is integrated appropriately into the brain. In the context of concussion symptoms, disruptions to the vestibular system can lead to difficulties in maintaining balance and cause common symptoms such as dizziness and vertigo. These vestibular symptoms can greatly affect an individual’s ability to perform daily activities.

Symptoms of Vestibular Dysfunction.

Individuals suffering from a concussion often report a variety of concussion symptoms related to vestibular dysfunction. Among the most common symptoms related to vestibular impairment are:

  • Dizziness: A sensation of feeling unsteady.
  • Vertigo: A spinning sensation, as if one’s surroundings are moving around them.
  • Imbalance: Difficulty maintaining a stable posture.
  • Nausea: Frequently accompanied (or triggered) by bouts of dizziness or motion sensitivity.
  • Motion Sensitivity: Overwhelming discomfort or disorientation in environments with excessive motion or visual stimuli, such as crowded spaces or while watching moving images.
  • Blurred Vision: Difficulties focusing or temporary loss of clear vision, often associated with movements or changes in position.
  • Headaches: Persistent or episodic headaches that may be exacerbated by movement.
  • Cognitive Impairment: Difficulties with brain fog, concentration, memory, and processing information, which can be indirectly related to vestibular dysfunction.
  • Fatigue: Excessive tiredness that may be partly due to the extra effort required to maintain balance and orientation.
  • Anxiety: as individuals find it increasingly difficult to participate in activities they once enjoyed.

Can a Concussion Cause Vestibular Problems?

A head injury can significantly impact the function of the vestibular system, leading to a range of symptoms that can complicate the recovery process for individuals with a concussion. The force of an impact that causes brain trauma can disrupt the brain’s central oculomotor and vestibular systems.

Master et al. (2018) examined the prevalence of vestibular pathology in children aged 5 to 18 who had a concussion. They found that 88% of their participants had issues related to vestibular disorders, and these impairments were strong predictors of prolonged recovery. In addition, Marcus et al. (2019) found similar prevalence rates of vestibular dysfunction in adults following a concussion (87%).

Common Vestibular Disorders Related to Concussion.

Leddy et al., (2021) highlight that vestibular disorders following a concussion are often linked to disruptions in neuroanatomical structures and pathways responsible for integrating sensory information regarding balance and spatial orientation. Disruptions or focal injuries to these pathways and structures can lead to significant vestibular dysfunction, manifesting as dizziness, imbalance, and impaired gaze stabilization. 

More specific disorders observed post-concussion include: 

Benign Paroxysmal Positional Vertigo

A common peripheral vestibular dysfunction that can result from a concussion is Benign Paroxysmal Positional Vertigo (BPPV) (Reimer et al., 2020). BPPV is characterized by brief (30-120 seconds) episodes of vertigo, typically triggered by changes in head movement. This condition is caused by dislodged tiny calcium carbonate crystals within the otolith organs of the inner ear. A concussion’s force can shake these crystals loose, allowing them to enter the semicircular canals where they do not belong. When the head is moved in certain directions, these dislodged crystals shift within the semicircular canals, sending abnormal signals to the brain about the body’s motion, leading to dizziness and vertigo.

Wang et al. (2021) examined the prevalence of BPPV at a pediatric concussion clinic and found 29% of concussed patients were diagnosed with BPPV. In addition, Marcus et al., (2019) found slightly higher rates of BPPV in an adult population following a concussion (38%).

Vestibular Migraine

Following a concussion, Arshad et al., (2017) found individuals with vestibular symptoms were commonly caused by vestibular migraine. Vestibular migraine is considered one of the central vestibular disorders as it represents a connection between the vestibular system and migraine mechanisms.

Vestibular migraines are characterized by episodes of vertigo, dizziness, and balance issues, often accompanied by the traditional symptoms of a migraine, such as light sensitivity, visual aura, and severe headache. The pathophysiology behind vestibular migraines post-concussion is not completely understood. Still, it is believed to involve sensitization of the central nervous system and disruptions in the brain’s processing of vestibular information. Clinically, vestibular migraine can look a lot like “difficult to treat” BPPV. 

Central Sensory Integration Dysfunction (Visual/Vestibular Mismatch)

Sensory integration refers to the brain’s ability to take in, organize, and interpret information from our senses to respond appropriately. Research by Campbell et al. (2021) suggests that ongoing vestibular symptoms post-concussion can be caused by central sensory integration dysfunction or a visual/vestibular mismatch. 

Specifically, after a concussion, the brain struggles to correctly process the signals it receives from the vestibular, visual, and proprioceptive systems. There may also be damage to the neural pathways that connect these systems to the brain’s centers for processing sensory information. Individuals with sensory integration problems may experience symptoms of vestibular dysfunction, such as an inability to focus in visually stimulating environments, heightened sensitivity to sound, and an overwhelming feeling of disorientation in crowded spaces.

Vestibular Hypofunction

Vestibular hypofunction is a peripheral vestibular disorder characterized by reduced or impaired function of the vestibular system. Patients with vestibular hypofunction often report a persistent sense of imbalance or unsteadiness, difficulty with rapid head movements, and a heightened sensitivity to complex visual environments.

The underlying cause of vestibular hypofunction following a concussion may involve damage to the peripheral vestibular system or to the neural pathways (such as the inferior vestibular nerve) that process vestibular information from the inner ear to the brain (Gard et al., 2022).

Vestibular therapy for individuals experiencing any of these vestibular concussion symptoms often involves specialized vestibular exercises by a trained vestibular therapist. 

At Complete Concussions, we pride ourselves on our comprehensive network of highly trained professionals who specialize in diagnosing and effectively treating vestibular problems associated with concussions. Complete Concussions is committed to delivering the highest standard of care for those suffering from vestibular dysfunction.

The Visual System and Concussion.

What is the Visual System?

The visual system is an intricate network encompassing the eyes, the pathways leading to the visual cortex, and the brain areas responsible for processing visual information. It plays a pivotal role in our interaction with the environment. This sensory system allows us to interpret shapes, colors, movement, and depth, enabling us to easily perform everyday tasks.

How Concussions Can Affect Visual Function.

Concussions can significantly compromise the visual system’s function. They can disrupt the brain’s direct and indirect pathways involved in visual processing. Such impacts can lead to visual disturbances, including blurred vision, double vision, difficulty with eye movements, and difficulty focusing.

These visual issues arise because concussions can affect the brain areas that control how the eyes move and work together and how visual information is processed and understood.

Some of the more common visual disorders associated with a concussion include:

Convergence Insufficiency and Accommodative Insufficiency

Following a concussion, patients often experience visual disturbances such as convergence insufficiency (CI) and accommodative insufficiency (AI). CI is a condition where the eyes do not work together properly while focusing on a nearby object, leading to difficulties in maintaining binocular vision and causing symptoms like double vision, eyestrain, headaches, and reading difficulties.

AI, on the other hand, is characterized by the inability of the eyes to maintain focus on objects at close range, resulting in blurred vision, eye fatigue, and headaches, particularly during activities such as reading or screen use.

These conditions stem from disruptions to the neural pathways that control the eye muscles and reflexes, often impacted by concussions. Galloway et al. (2017) examined common visual disorders after concussion, and the most common visual impairment was CI (47%), followed by AI (42%).

Eye Movement Disorders (Oculomotor Dysfunction)

Following a concussion, individuals may experience a range of eye movement disorders or oculomotor dysfunction. These disorders can manifest as difficulty tracking moving objects, challenges with rapid eye movements between targets (saccadic dysfunction), and an inability to smoothly follow a moving object (pursuit dysfunction). Symptoms may include blurred or double vision, eye strain, headaches, and reading difficulties stemming from the brain’s impaired ability to control and coordinate the eyes. Galloway et al., (2017) found 21% of concussed patients in their study had eye movement disorders.

Binocular Vision Problems

Post-concussion, many individuals report experiencing binocular vision problems pertaining to the eyes’ ability to work together as a unified system. Disruptions in binocular vision can manifest as visual misalignment, where the eyes no longer coordinate in a way that produces a single, clear image. This condition can lead to symptoms such as double vision, eye strain, headaches, and difficulties with depth perception. Galloway et al., (2017) found 62% of their concussed patients suffered from binocular problems.

Common Visual Symptoms Post Concussion.


  • Blurred Vision: Difficulty in seeing details clearly.
  • Double Vision: Seeing two images of a single object – which can impair depth perception.
  • Difficulty with Eye Movements: Problems in smoothly tracking moving objects or shifting focus between targets, causing discomfort and affecting coordination.
  • Light Sensitivity: Increased discomfort in bright environments or when exposed to bright lights.
  • Difficulties in Focusing: Trouble in maintaining clear vision over time, especially when shifting focus from near to far objects.
  • Visual Fatigue: Experiencing tiredness or strain in the eyes much quicker than usual, especially after tasks that require intense visual concentration.
  • Challenges with Visual-spatial Skills: Difficulty in judging distances, depth, and the spatial relationship between objects, impacting movement and navigation.

Diagnosing Vestibular and Visual Dysfunctions Post-Concussion.

The visual and vestibular systems are intricately linked, as they both play crucial roles in maintaining balance, spatial orientation, and coordinating eye movements. Visually-based information and vestibular input work together to help the brain understand and respond to changes in the environment, facilitating tasks such as walking and reading. Clinically, when subtyping concussion, it is common to consider these systems together because disruptions in one can significantly impact the other. The overlap in symptoms like dizziness, blurred vision, and difficulties with eye movements underscores the interconnectedness of these systems, making comprehensive assessment and treatment essential for effective concussion management.


Leddy et al., (2021) stress that a thorough patient history is crucial before assessing vestibulo ocular symptoms because it provides a comprehensive context for the presenting symptoms and aids in identifying potential underlying causes. Understanding the patient’s medical background, injury history, medications, and psychosocial factors can uncover factors related to vestibular disorders or other comorbidities that might contribute to or exacerbate symptoms. 

Tests Used to Assess Vestibular and Visual Functions.

Healthcare professionals will use a variety of tests when assessing for visual and vestibular dysfunction. Some of these tests include:

Vestibular Ocular Motor Screening (VOMS)

The VOMS is a crucial tool in the evaluation of individuals with a concussion to identify abnormalities in vestibular and ocular motor functioning (Elbin et al., 2018). This screening involves a series of tests that assess gaze stability, vestibulo ocular reflex, horizontal and vertical saccades, smooth pursuit, visual motion sensitivity, and convergence. Taylor et al., (2022) reported 41% of their concussed subjects had abnormalities on VOMS testing.

Through the VOMS, healthcare professionals can detect vestibular and ocular motor dysfunctions, aiding in the diagnosis and vestibular therapy for concussion patients. Read more about this test here.

Monocular Accommodation Testing

Leddy et al., (2021) recommend visual testing of monocular accommodation, which maintains a clear image of an object as its distance varies. Studies have shown that abnormal accommodation is common post-concussion and has been associated with a prolonged recovery. 

Vestibulo Ocular Reflex (VOR) Testing

VOR testing examines the ability of the eyes to maintain a stable gaze on a fixed point while the head is moving. Corwin et al., (2015) found that 69% of children post-concussion had abnormalities in vestibulo-ocular reflex function.

BPPV Testing

This diagnostic test involves maneuvers that reposition the head to trigger and identify BPPV, which helps to guide targeted vestibular exercises.

Static and Postural Stability Testing

Static and postural stability testing, such as the Balance Error Scoring System (BESS), provides a standardized method to evaluate subtle postural control deficits. The BESS test involves performing a series of balance tasks under varying conditions. However, research shows this test is useful only within the first 4-5 days post-injury. As such, Leddy et al., (2021) also recommend eyes open and closed tandem stance, tandem gait, and dual-task tandem gait testing as more reliable and sensitive tests for identifying static and dynamic balance disorders. Taylor et al., (2022) found 76% of their concussed subjects had abnormal results on postural stability testing.  In addition, Corwin et al., (2015) found 80% of concussed patients struggled with tandem gait.

Motion Sensitivity Testing (MST)

Motion Sensitivity Testing involves a series of head and body movements designed to identify motion-provoked dizziness in individuals with a concussion. This test assesses the patient’s tolerance to motion and their vestibular system’s response to changes in position. The results from this test are crucial for developing personalized vestibular therapy exercises that aim to reduce motion sensitivity.

Together, these tests provide a detailed assessment of visual and vestibular function, making it possible to develop targeted vestibular rehabilitation strategies that address the specific challenges faced by individuals recovering from a concussion. For more information about vision testing, read our past article here

Visual and Vestibular Therapy Post Concussion.

Treatment for Visual and Vestibular Dysfunctions.

Vestibular therapy for patients with a concussion involves a multidisciplinary approach tailored to the specific needs and symptoms of each individual. Rehabilitation efforts are focused on restoring normal function, reducing symptoms, and improving quality of life. Oftentimes, patients undergoing vestibular rehabilitation will also require cervical rehabilitation, such as manual therapy and exercise, as symptoms and dysfunctions are often interconnected.

Vestibular treatment approaches commonly include:

Vestibular Rehabilitation Therapy

Vestibular rehabilitation is a specialized form of vestibular therapy to alleviate inner ear balance disorders. It uses a series of exercises to improve balance, minimize dizziness, and enhance overall stability. These exercises are designed to retrain the brain to recognize and process vestibular input more effectively, such as gaze stabilization exercises and vestibulo ocular reflex exercises.

Vision Therapy

Vision therapy consists of a series of visual exercises designed to improve visual skills such as tracking, focusing, peripheral vision, and eye teaming. It can also help address eye strain, headaches, and difficulties with visual processing.

Canal Repositioning Maneuvers for BPPV

An effective treatment strategy for BPPV is canal repositioning maneuvers, such as the Epley maneuver, designed to move the dislodged otoconia back to their proper position within the inner ear. These maneuvers involve a series of specific head movements performed by a trained vestibular therapist, which can provide immediate relief from vertigo symptoms.

Balance Training Exercises

Balance exercises are designed to challenge the vestibular system to improve balance and stability. These might involve standing on one foot, walking on uneven surfaces, or exercises that mimic daily activities.

Habituation Exercises

Habituation exercises involve repeated exposure to triggering movements in a controlled manner, which helps the brain learn how to desensitize its response.

The effectiveness of vestibular rehabilitation varies among individuals, and it may take time to see improvements. Vestibular therapy is highly individualized, based on thorough assessment and diagnosis by healthcare professionals. This person-centered approach ensures that therapy is aligned with each patient’s specific challenges and progress, enhancing the effectiveness of treatment and promoting a faster return to daily activities.


The path towards recovery from a concussion is unique to each individual. The significance of early detection and treatment for visual and vestibular dysfunctions cannot be overstated. Initiating appropriate interventions promptly not only reduces the duration and severity of symptoms but is pivotal in navigating the complex path to recovery and ensuring a return to a fulfilling life post-concussion.


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