Boston Carpal Tunnel Questionnaire: Facts Every Clinician Should Know

What is the Boston Carpal Tunnel Questionnaire?

The Boston Carpal Tunnel Questionnaire (BCTQ) is a validated, patient-reported outcome measure (PROM) specifically designed to assess symptom severity and functional status in patients with carpal tunnel syndrome (CTS). Developed in 1993 by researchers at Brigham and Women's Hospital in Boston, Massachusetts, the BCTQ has become the gold standard assessment tool for evaluating CTS-related impairment in both clinical practice and research settings.

Key Characteristics:

• Disease-specific: Designed exclusively for carpal tunnel syndrome assessment
• Self-administered: Patients complete independently in 5-10 minutes
• Evidence-based: Extensively validated with strong psychometric properties
• Widely adopted: Most frequently used outcome measure in CTS clinical trials
• Free to use: No licensing fees or copyright restrictions

Historical Development & Alternative Names

Original Publication

The BCTQ was first published in The Journal of Bone & Joint Surgery (November 1993, Volume 75, Issue 11, Pages 1585-1592) by Levine and colleagues. Notably, the authors did not assign a formal name to the questionnaire in their original publication, which has led to multiple naming conventions in medical literature.

Alternative Names You May Encounter:

1. Levine Scale or Levine Questionnaire
2. Brigham and Women's Carpal Tunnel Questionnaire
3. Carpal Tunnel Syndrome Assessment Questionnaire
4. CTS Instrument
5. Brigham Carpal Tunnel Questionnaire

Important Note: Despite the varying nomenclature, all these names refer to the same assessment tool with identical content and scoring methodology.

Questionnaire Structure & Components

The BCTQ consists of two independent subscales that evaluate different dimensions of carpal tunnel syndrome impact:

1. Symptom Severity Scale (SSS)

Purpose: Assesses the intensity and frequency of CTS symptoms
Number of Items: 11 questions
Rating Scale: 5-point Likert scale (1 = no symptoms to 5 = very severe symptoms)

Domains Evaluated:

• Pain intensity (day and night)
• Numbness severity
• Tingling/paresthesia frequency
• Weakness in hand or wrist
• Nocturnal symptoms and sleep disruption
• Difficulty with fine motor tasks (writing, buttoning, holding objects)

Time Frame: Symptoms during a typical 24-hour period over the past 2 weeks

2. Functional Status Scale (FSS)

Purpose: Measures difficulty performing specific daily activities
Number of Items: 8 questions
Rating Scale: 5-point Likert scale (1 = no difficulty to 5 = cannot perform activity)

Functional Activities Assessed:

1. Writing
2. Buttoning clothes
3. Holding a book while reading
4. Gripping telephone handset
5. Opening jars
6. Household chores
7. Carrying grocery bags
8. Bathing and dressing

Scoring Methodology & Interpretation

Calculation Method

Each subscale generates an independent score calculated as:

Score = (Sum of individual item responses) ÷ (Number of items)

• SSS Score Range: 1.0 to 5.0
• FSS Score Range: 1.0 to 5.0

Score Interpretation Guidelines

Minimal Clinically Important Difference (MCID)

Research has established the MCID for the Symptom Severity Scale at 1.04 points (commonly rounded to 1.0 for practical use). This represents the smallest change in score that patients perceive as clinically meaningful improvement.

Clinical Application: A reduction of ≥1.0 points on the SSS following treatment indicates clinically significant improvement from the patient's perspective.

Note: The MCID for the Functional Status Scale has not yet been definitively established in the literature.

Important Scoring Considerations:

• Unanswered questions are excluded from the calculation (not scored as zero)
• Both scales should be scored and interpreted independently
• Higher scores consistently indicate worse symptoms or greater functional impairment
• Scores can be tracked longitudinally to monitor disease progression or treatment response

Psychometric Properties & Validation

The BCTQ has undergone extensive psychometric evaluation across multiple international studies, demonstrating robust measurement properties.

Validity

Content & Face Validity

Initial development included consultation with CTS patients and hand surgery experts to ensure questionnaire items accurately reflect the patient experience and clinical manifestations of carpal tunnel syndrome.

Construct Validity

Evidence Level: Strong (based on 932+ patients across 8 studies)

The BCTQ demonstrates expected correlations with:

• Other upper extremity outcome measures (DASH, MHQ): Spearman r = 0.71-0.90
• Objective clinical measures (grip strength, pinch strength)
• Electrodiagnostic testing results
• Patient satisfaction following treatment

Key Finding: BCTQ scores show 2-4 times greater sensitivity to clinical change than objective measures of strength and sensation.

Reliability

Test-Retest Reliability

Measurement Interval: 2-7 days
Results: Excellent reliability across studies

• SSS: Pearson correlation coefficient = 0.91 (range 0.64-0.91 across studies)
• FSS: Pearson correlation coefficient = 0.93 (range 0.71-0.93 across studies)

Internal Consistency

Method: Cronbach's alpha coefficient

• SSS: α = 0.80-0.90 (excellent internal consistency)
• FSS: α = 0.88-0.93 (excellent internal consistency)

Responsiveness to Change

Evidence Level: Strong (based on 986+ patients across 9 studies)

The BCTQ demonstrates superior responsiveness compared to:

• Generic health status measures (SF-36)
• Region-specific measures (DASH)
• Objective clinical measures (strength, sensation, electrodiagnostic studies)

Clinical Significance: The BCTQ is particularly sensitive to detecting meaningful change following both surgical and conservative CTS interventions.

Cross-Cultural Validation

The BCTQ has been successfully translated and validated in 20+ languages, including:

• Spanish, French, German, Italian, Portuguese
• Chinese, Japanese, Korean, Thai, Turkish
• Arabic, Persian, Dutch, Swedish, Norwegian

Each validated translation demonstrates psychometric properties comparable to the original English version.

Clinical Applications & Use Cases

Primary Clinical Applications

1. Treatment Outcome Monitoring

The BCTQ serves as a primary outcome measure in clinical trials evaluating:

• Surgical interventions (open carpal tunnel release, endoscopic release)
• Conservative treatments (splinting, corticosteroid injections, physical therapy)
• Emerging therapies (ultrasound-guided hydrodissection, laser therapy)

Advantage: More responsive to patient-perceived change than electrodiagnostic testing or grip strength measurements.

2. Longitudinal Disease Tracking

Enables clinicians to:

• Monitor symptom progression over time
• Identify patients requiring escalation of care
• Evaluate treatment effectiveness at follow-up appointments
• Document patient-reported outcomes for quality improvement initiatives

3. Pre- and Post-Surgical Assessment

Recommended Timeline:

• Baseline assessment prior to carpal tunnel release surgery
• Follow-up assessments at 3 months, 6 months, and 12 months post-operatively

Expected Improvement: Studies show average SSS improvement of 1.5-2.5 points following successful surgical intervention.

4. Clinical Research & Registry Data

The BCTQ is the most frequently cited outcome measure in carpal tunnel syndrome research, facilitating:

• Meta-analyses and systematic reviews
• Comparative effectiveness research
• Practice pattern analysis
• Healthcare quality reporting

Screening Limitations

Important: The BCTQ is not designed or validated as a diagnostic tool for carpal tunnel syndrome. Diagnosis requires:

• Clinical examination (Phalen's test, Tinel's sign, provocative maneuvers)
• Patient history and symptom pattern
• Electrodiagnostic studies (nerve conduction velocity, electromyography)

Recent studies exploring the BCTQ's potential screening utility in high-risk populations show promise, but this remains an off-label application requiring further validation.

Frequently Asked Questions

Q1: Can the BCTQ diagnose carpal tunnel syndrome?

A: No. The BCTQ is an outcome measurement tool, not a diagnostic instrument. CTS diagnosis requires clinical examination, patient history, and often electrodiagnostic testing. The BCTQ assesses symptom severity and functional impact in patients with already-confirmed CTS.

Q2: How often should I administer the BCTQ?

A: Recommended intervals depend on clinical context:

• Conservative treatment monitoring: Every 4-6 weeks
• Pre-surgical baseline: Within 2-4 weeks before surgery
• Post-surgical follow-up: 3 months, 6 months, and 12 months
• Research protocols: Per study design, typically at predefined timepoints

Q3: What constitutes a clinically meaningful improvement?

A: A reduction of ≥1.0 points on the Symptom Severity Scale represents the minimal clinically important difference (MCID). Changes smaller than this may not be perceived as meaningful by patients.

Q4: Should I use the SSS and FSS together or separately?

A: Both scales should be administered and scored independently. While they often correlate, some patients experience symptom-function discordance:

• High symptoms but maintained function (early/mild CTS, highly motivated patients)
• Lower symptoms but significant functional limitations (severe CTS with sensory adaptation, compensatory strategies)

Both scales provide complementary information about disease impact.

Q5: Is the BCTQ suitable for bilateral carpal tunnel syndrome?

A: Yes. Administer the questionnaire for each hand separately when bilateral CTS is present. Patients should specify which hand they're rating and complete two separate questionnaires. Bilateral symptoms often differ in severity and functional impact.

Q6: Can I modify the BCTQ questions?

A: Modifying validated questionnaires compromises their psychometric properties and invalidates comparative data. Use the questionnaire as published. If your clinical needs differ, consider:

• Adding supplementary questions separately (don't mix with BCTQ scoring)
• Using a different outcome measure better suited to your needs
• Using the BCTQ alongside complementary measures

Q7: What if patients skip questions?

A: The scoring methodology accounts for missing data:

• Calculate the mean of answered questions only
• Exclude unanswered items from both numerator and denominator
• If ≥50% of items are skipped, the scale score is considered invalid

Encourage complete responses for most accurate assessment.

Q8: Does the BCTQ work for occupational screening?

A: The BCTQ is not validated for screening asymptomatic populations. Recent studies exploring this application show mixed results. For occupational health:

• Use validated occupational screening tools designed for asymptomatic workers
• Reserve BCTQ for workers with suspected or confirmed CTS
• Combine with ergonomic assessment and job-specific functional evaluations

Q9: Are there age-related score differences?

A: Some research suggests differential item functioning on specific questions (particularly nocturnal symptoms) based on age and gender. However, these differences are relatively small. The BCTQ remains valid across adult age groups when interpreted appropriately.

Q10: Can the BCTQ predict surgical outcomes?

A: Baseline BCTQ scores show weak predictive value for surgical outcomes. Higher pre-operative scores sometimes correlate with greater absolute improvement, but multiple factors influence surgical success:

• Electrodiagnostic severity
• Duration of symptoms
• Patient comorbidities (diabetes, obesity, hypothyroidism)
• Psychosocial factors

BCTQ is best used for monitoring outcomes rather than predicting them.

Conclusion

The Boston Carpal Tunnel Questionnaire represents a well-validated, patient-centered outcome measure that has earned its position as the gold standard for assessing carpal tunnel syndrome impact. Its strong psychometric properties, ease of administration, and disease-specific sensitivity make it invaluable for both clinical practice and research.

Key Takeaways for Healthcare Professionals:

1. Use the BCTQ as part of comprehensive CTS assessment (not as a standalone diagnostic tool)
2. Track both SSS and FSS independently for complete understanding of disease impact
3. Interpret changes of ≥1.0 points as clinically meaningful on the Symptom Severity Scale
4. Administer at regular intervals to monitor treatment response and disease progression
5. Combine with objective measures (electrodiagnostics, clinical examination) for optimal patient management

Future Directions:

Ongoing research continues to refine BCTQ interpretation, including:

• Development of severity-adjusted norms
• Investigation of differential item functioning
• Exploration of item response theory applications
• Validation of abbreviated versions (CTS-6)
• Digital administration and automated scoring platforms

As carpal tunnel syndrome remains one of the most common peripheral neuropathies affecting millions worldwide, the BCTQ will continue to play a central role in evaluating patient outcomes and advancing evidence-based care.