Complete Guide to the Balance Error Scoring System (BESS)

Introduction

When an athlete takes a hard hit on the field or a patient experiences a vestibular issue, how do clinicians quickly and accurately assess their balance? The answer often lies in a simple yet powerful tool that requires nothing more than a foam pad, a stopwatch, and a trained eye.

The Balance Error Scoring System (BESS) has become a cornerstone assessment in sports medicine, concussion management, and rehabilitation settings since its development in the late 1990s. Unlike expensive force plates or computerised balance systems, BESS offers a practical, cost-effective solution that can be administered in under 10 minutes, on a sideline, in a clinic, or anywhere balance assessment is needed.

This comprehensive guide will walk you through everything you need to know about the BESS balance test: from understanding its foundational principles to performing accurate assessments, interpreting scores, and applying modified versions for specific populations. Whether you're a sports medicine professional, athletic trainer, physical therapist, or researcher, you'll discover how to implement this validated tool to enhance your balance assessment protocols and improve patient outcomes.

What is the Balance Error Scoring System?

The Balance Error Scoring System (BESS) is a standardised clinical balance assessment tool designed to evaluate postural stability through direct observation. Developed by researchers at the University of North Carolina in 1995, BESS was created to provide a reliable, objective method for assessing balance deficits, particularly following concussions and mild traumatic brain injuries.

Core Principles

The BESS operates on a fundamental principle: challenging the body's balance system by systematically altering sensory inputs and support surfaces. By reducing the base of support (through different stance positions) and changing surface stability (firm versus foam), the test stresses the vestibular, proprioceptive, and visual systems that maintain postural control.

Test Components

The standard BESS consists of six 20-second testing conditions that combine three stance positions with two surface types:

• Double-leg stance: Feet together, hands on hips
• Single-leg stance: Standing on the non-dominant leg
• Tandem stance: Non-dominant foot behind dominant foot in heel-to-toe position

Each stance is performed on both a firm surface (typically the ground or floor) and an unstable foam surface (medium-density foam pad).

Scoring Mechanism

Unlike many balance tests that measure stability through force plates or technology, BESS uses an error-counting system. Trained examiners observe participants during each 20-second trial and count specific balance errors. The total number of errors across all six conditions becomes the BESS score, with higher scores indicating poorer balance performance.

Clinical Applications

BESS has found widespread adoption in concussion baseline testing, post-injury assessments, return-to-play protocols, vestibular disorder evaluation, and research on balance impairments across various populations. Its simplicity and minimal equipment requirements make it particularly valuable in settings where sophisticated balance technology isn't available or practical.

Required Equipment & Setup

One of BESS's greatest advantages is its minimal equipment requirement, making it accessible for virtually any clinical or athletic setting.

Essential Equipment Checklist:

• Foam pad: Medium-density foam (Airex Balance Pad or equivalent), approximately 20" × 16" × 2.5" thick
• Stopwatch or timer: Any standard timer capable of measuring 20-second intervals
• BESS scoring sheet: Printed form for documenting errors
• Firm, level surface: Non-carpeted floor recommended for consistency
• Clipboard or writing surface: For recording scores during testing

Optional but Recommended:

• Video recording device for documentation and training purposes
• Second examiner for inter-rater reliability verification during training

Environment Requirements

The testing environment significantly impacts results. Ensure the following conditions:

• Quiet space: Minimise distractions and noise that could affect concentration
• Adequate lighting: Sufficient illumination for the examiner to observe errors
• Level surface: Ensure the firm surface is flat and stable
• Safety considerations: Clear the area of obstacles; have a spotter nearby if needed
• Consistent conditions: Use the same environment for baseline and follow-up testing when possible

Pre-Test Preparation

Before beginning, verify that the participant is wearing appropriate footwear (shoes removed, testing conducted in socks or barefoot), understands the testing protocol, and has not engaged in strenuous exercise immediately before testing, which could affect balance performance.

BESS Test Protocol & Procedure

Administering the BESS requires strict adherence to standardised procedures to ensure reliable, valid results.

Pre-Test Instructions

Begin by explaining the test to the participant: "You will be asked to maintain three different stances for 20 seconds each, with your hands on your hips and eyes closed. I'll be counting any errors you make during each trial. Do your best to remain as still as possible."

Demonstrate each stance position with eyes open, then allow the participant to practice briefly. Identify the dominant leg by asking which leg they would use to kick a ball.

Step-by-Step Testing Procedure

Condition 1: Double-Leg Stance (Firm Surface)

• Participant stands with feet together, touching
• Hands placed on iliac crests (hips)
• Eyes closed when timer begins
• Maintain position for 20 seconds
• Examiner counts and records errors

Condition 2: Single-Leg Stance (Firm Surface)

• Stand on the non-dominant leg
• Opposite hip flexed to approximately 30 degrees, knee flexed to approximately 45 degrees
• Hands on hips, eyes closed
• 20-second duration

Condition 3: Tandem Stance (Firm Surface)

• Non-dominant foot positioned directly behind dominant foot (heel-to-toe)
• Weight distributed evenly between both feet
• Hands on hips, eyes closed
• 20-second duration

Conditions 4-6: Repeat on Foam Surface Repeat the same three stances (double-leg, single-leg, tandem) on the foam pad, following identical procedures.

Important Administration Notes:

• Begin timing when the participant closes their eyes and achieves the testing position
• If the participant cannot maintain the stance for more than 5 seconds, assign the maximum error score (10 errors) for that condition
• Provide minimal verbal encouragement; avoid giving corrective feedback during trials
• Allow 15-30 seconds rest between conditions
• Total administration time: approximately 5-7 minutes

Examiner Positioning

Stand 2-3 feet away from the participant at a 45-degree angle, allowing clear observation of the feet, hips, and trunk. Maintain consistent positioning across all trials.

Scoring System & Error Identification

The BESS uses an error-accumulation scoring system where examiners count specific deviations from the proper testing stance during each 20-second trial.

Errors to Count (1 point each):

1. Hands lifted off the iliac crests: Any removal of one or both hands from the hips
2. Opening eyes: Any instance of opening the eyes during the trial
3. Step, stumble, or fall: Any movement of the feet from the testing position
4. Hip abduction or flexion >30 degrees: Moving the non-stance leg away from the body or altering the required position
5. Lifting forefoot or heel: Raising any part of the foot off the ground
6. Remaining out of testing position >5 seconds: Sustained deviation from the proper stance

Scoring Guidelines:

• Maximum errors per trial: 10 (even if more errors occur)
• Total possible score: 60 points (10 errors × 6 conditions)
• Recording: Tally errors in real-time using a scoring sheet
• Multiple simultaneous errors: Count as a single error if they occur at the same moment
• Continuous errors: Count once per second when an error persists (e.g., if hands remain off hips for 3 seconds, count 3 errors)

Scoring Example:

If during the single-leg stance on foam, a participant opens their eyes once (1 error), lifts their hands off their hips twice (2 errors), and takes a step to maintain balance three times (3 errors), the trial score would be 6 errors.

Common Scoring Challenges:

Examiners must distinguish between minor adjustments and actual errors. Brief micro-corrections lasting less than one second typically aren't counted, while sustained deviations or obvious balance losses are. Proper training and experience improve inter-rater reliability, which research shows can reach excellent levels (ICC > 0.85) with standardised protocols.

Final Score Calculation:

Sum all errors across the six conditions. A higher total score indicates poorer balance performance. Document both the total score and individual condition scores, as specific deficits (particularly on foam surfaces) can provide clinical insights.

Normative Data & Interpretation

Understanding what constitutes a "normal" BESS score is essential for clinical interpretation and identifying meaningful balance deficits.

General Population Norms

Research has established normative BESS scores across various populations, though scores vary based on age, athletic participation, and testing conditions:

Post-Concussion Interpretation

BESS scores typically increase (worsen) immediately following concussion, with research showing:

• Acute phase (0-3 days post-injury): Average increase of 5-9 errors compared to baseline
• Sub-acute phase (3-7 days): Scores often return toward baseline in uncomplicated cases
• Persistent symptoms (>7 days): Sustained elevation may indicate ongoing balance dysfunction

Clinical Significance Thresholds

• Minimal detectable change: Approximately 5-7 errors represent a meaningful change
• Baseline comparison: Scores ≥5 points higher than individual baseline warrant clinical attention
• Return-to-play criteria: BESS score should return to within 3-5 points of baseline before considering clearance

Interpretation Caveats

Several factors influence BESS scores and must be considered during interpretation:

• Practice effects: Scores typically improve 2-3 points with repeated testing due to learning
• Fatigue: Physical exhaustion can elevate scores by 3-5 errors
• Time of day: Some studies suggest circadian variations in balance performance
• Surface conditions: Foam pad firmness affects difficulty; newer foam is more challenging
• Individual variability: Some healthy individuals naturally score higher without pathology

Using BESS in Clinical Decision-Making

BESS should never be used in isolation for concussion diagnosis or return-to-play decisions. Instead, integrate BESS findings with symptom reporting, cognitive testing, and other clinical assessments. The test is most valuable when baseline scores are available for individualized comparison, and when administered at multiple time points to track recovery trajectories.

Modified BESS Variations

While the standard BESS protocol is well-established, several modified versions have been developed to address specific clinical needs, time constraints, or population considerations.

The 3-Condition Modified BESS (m-BESS)

The most common modification eliminates the firm surface conditions, testing only the three stances on foam:

• Double-leg stance on foam
• Single-leg stance on foam
• Tandem stance on foam

Advantages: Reduces administration time to approximately 2-3 minutes while maintaining sensitivity to balance impairments. Research demonstrates a high correlation (r = 0.85-0.92) between m-BESS and full BESS scores. Maximum score: 30 points (10 errors × 3 conditions).

Clinical Applications: Ideal for sideline concussion assessments, large-scale baseline testing screenings, and settings where time efficiency is critical.

Sport Concussion Assessment Tool (SCAT) BESS

The SCAT protocol, used internationally in sports medicine, incorporates a modified BESS focusing on the most challenging conditions. This version is embedded within the comprehensive SCAT assessment battery.

Eyes-Open BESS Modifications

For populations with severe balance impairments (elderly, neurologically impaired patients), some clinicians use an eyes-open protocol to improve safety and feasibility. While this reduces sensitivity, it allows assessment of individuals who cannot safely complete eyes-closed trials.

Pediatric Modifications

When testing children under 10 years old, some researchers recommend:

• Shortened trial duration (10-15 seconds instead of 20)
• Additional demonstration and practice opportunities
• Age-appropriate normative comparisons
• Modified instructions using child-friendly language

Selecting the Appropriate Version

Choose the BESS variation based on your specific context:

• Standard BESS: Research studies, comprehensive clinical evaluations, when time permits
• m-BESS: Sideline assessments, mass baseline screenings, follow-up monitoring
• SCAT BESS: Standardised sports concussion evaluations following international protocols
• Modified protocols: Special populations requiring accommodations

Regardless of the version selected, maintain consistency in protocol use for baseline and follow-up testing to ensure valid comparisons.

Conclusion & Resources

The Balance Error Scoring System has earned its place as an essential tool in sports medicine and clinical balance assessment. Its combination of simplicity, minimal equipment requirements, and solid research foundation makes it uniquely valuable for settings ranging from athletic sidelines to rehabilitation clinics.

Key Takeaways:

• BESS provides a quick, cost-effective method for assessing postural stability through standardised observation
• The test challenges balance by systematically altering stance positions and surface stability
• Proper administration requires training, but the protocol is straightforward and accessible
• BESS is most powerful when used with baseline testing and integrated into comprehensive assessment protocols
• While limitations exist, particularly regarding subjective scoring and modest sensitivity, the benefits far outweigh the drawbacks for practical clinical use

Implementing BESS in Your Practice

Success with BESS depends on several factors: invest time in proper training to ensure scoring reliability, establish baseline testing programs for at-risk populations, maintain standardized testing conditions and protocols, integrate BESS with other assessment tools rather than using it in isolation, and document scores carefully to track changes over time and inform clinical decisions.

Frequently Asked Questions (FAQ)

How long does the Balance Error Scoring System take?

The complete BESS assessment takes approximately 5-7 minutes to administer. Each of the six stances is tested for 20 seconds, totaling 2 minutes of actual testing time. The additional time accounts for instructions, transitions between conditions, brief rest periods, and score recording. The modified BESS (m-BESS), which uses only three foam surface conditions, can be completed in 2-3 minutes, making it ideal for sideline assessments or large-scale screening situations.

Is the Balance Error Scoring System reliable?

Yes, research demonstrates that BESS is reliable when administered by trained examiners following standardized protocols. Inter-rater reliability coefficients range from 0.78 to 0.92, indicating good to excellent agreement between different examiners. Intra-rater reliability is even higher (0.84-0.96), showing that individual examiners score consistently. However, test-retest reliability is more moderate (0.60-0.74) due to practice effects—participants naturally improve with repeated exposure. For optimal reliability, ensure examiners receive proper training, use standardized scoring criteria, and when possible, compare scores to individual baseline rather than relying solely on normative data.

What does the BESS measure?

BESS measures postural stability—the ability to maintain equilibrium in challenging stance positions with eyes closed. Specifically, it assesses the integration of three sensory systems involved in balance: the vestibular system (inner ear), proprioception (position sense from muscles and joints), and the somatosensory system. By eliminating visual input (eyes closed) and altering the support surface (firm versus foam), BESS challenges these systems and reveals deficits in postural control. Higher error counts indicate impaired balance, which may result from concussion, vestibular dysfunction, lower extremity injury, or other conditions affecting neuromuscular function.

What is a BESS assessment?

A BESS assessment is a clinical balance evaluation where a participant performs six different stance positions (three stances on a firm surface, three on foam) for 20 seconds each with their eyes closed and hands on their hips. A trained examiner observes and counts specific balance errors—such as opening eyes, lifting hands off hips, or stepping out of position. The total error count across all six trials provides an objective measure of balance function. BESS assessments are commonly used in concussion management for baseline testing, post-injury evaluation, and monitoring recovery, but they're also valuable in assessing vestibular disorders, lower extremity injuries, and age-related balance decline.

Can I use BESS without baseline testing?

While BESS can be administered without baseline scores, its clinical utility is significantly enhanced when baseline measurements are available. Individual baseline comparison allows you to detect meaningful changes specific to that person, rather than relying solely on population norms, which may not account for natural variability. That said, if baseline testing wasn't performed, you can still use BESS by comparing post-injury scores to age-matched normative data, tracking improvement across serial testing sessions, and integrating BESS findings with other clinical assessments. Research shows that scores 5+ errors above population norms warrant clinical attention even without individual baseline data.

What training is required to administer BESS?

BESS can be learned relatively quickly, but proper training is essential for reliable scoring. Recommended training includes studying the standardised protocol and error definitions, observing experienced examiners administer the test, practising with video examples to improve error identification accuracy, and achieving agreement with expert scorers (>90% scoring consistency). Many sports medicine organisations offer BESS training workshops or online modules. Athletic trainers, physical therapists, physicians, and other healthcare providers can become proficient BESS administrators, typically after 2-3 hours of focused training and practice with 10-20 assessments.