EHI-10: Edinburgh Handedness Inventory

Reviewed by: Constantin Rezlescu | Associate Professor | UCL Psychology

Introduction

The Edinburgh Handedness Inventory (EHI) is the most widely used standardized assessment for determining hand preference and the degree of handedness in research and clinical settings. Originally developed by Oldfield (1971) as a 20-item questionnaire, the 10-item short form (EHI-10) provides an efficient yet comprehensive evaluation of hand dominance patterns for common daily activities.

With thousands of citations across neuroscience, psychology, and medical literature, the EHI has become the international standard for handedness assessment, valued for its simplicity, reliability, and ability to capture both the direction and strength of hand preference.

Understanding Handedness as Neural Organization

Handedness is a fundamental aspect of human neurological organization, reflecting underlying brain lateralization patterns. It represents the preferential use of one hand over the other for skilled motor activities, which corresponds to contralateral hemispheric dominance in the brain.

Population distribution:

• Approximately 90% of people are right-handed
• 8-10% are left-handed
• 1-2% show mixed or ambidextrous patterns

Understanding an individual’s handedness is crucial for neuroscience research, clinical neuropsychology, and studies investigating brain-behavior relationships, as it provides insights into hemispheric specialization for language, motor control, and other cognitive functions.

Importantly, handedness is not simply a binary trait but exists on a continuum from strong left to strong right preference, with varying degrees of consistency across different activities.

Theoretical Foundation

The EHI is grounded in theories of cerebral lateralization and functional hemispheric asymmetry. The scale was developed based on observations that hand preference reflects the dominant motor cortex, which is typically contralateral to the preferred hand.

For most right-handed individuals, the left hemisphere is dominant for both motor control and language, while left-handed individuals show more variable patterns of lateralization. This relationship between handedness and brain organization makes the EHI valuable not just for assessing motor preference, but as a window into broader patterns of neural organization.

The inventory’s design recognizes that handedness is not uniform across all activities—some tasks may show stronger preference than others, and individuals may demonstrate mixed patterns. The laterality quotient (LQ) calculation allows researchers to quantify both:

• Direction: Left vs. right hand preference
• Strength: Strong, mixed, or ambidextrous patterns

This dimensional approach has proven particularly valuable in neuroimaging research, where handedness serves as a predictor of language lateralization and other functional brain asymmetries.

🧠 Research Essential: The EHI is considered the gold standard for handedness assessment in neuroscience research, cited in thousands of studies investigating brain lateralization and cognitive function.

Key Features

Assessment Characteristics

• 10 common activities representing diverse motor functions
• 2-3 minutes completion time
• Ages 6+ through adult (reading ability required)
• Laterality quotient (LQ) calculation on -100 to +100 scale
• Free for research use worldwide

Hand Preference Dimensions Assessed

• Fine motor control – Writing, drawing, precision tasks
• Tool manipulation – Scissors, knife, implements
• Gross motor actions – Throwing, sweeping, strength activities
• Bimanual coordination – Tasks requiring two-handed control
• Preference strength – Strong vs. mixed hand dominance patterns
• Consistency – Stable vs. variable hand use across activities

Research and Clinical Applications

• Pre-surgical planning – Language lateralization for brain procedures
• Neuroscience research – Brain lateralization and hemispheric specialization studies
• Neuropsychological assessment – Baseline measurement for cognitive testing
• Neuroimaging studies – Control variable in fMRI, EEG, and PET research
• Language lateralization – Predicting hemispheric dominance for language
• Clinical neuropsychology – Evaluation following brain injury or stroke
• Developmental research – Motor development and lateralization emergence
• Cross-cultural neuroscience – Handedness prevalence across populations

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Assess hand preference and calculate your laterality quotient across 10 common activities.

Scoring and Interpretation

Response Format

For each activity, participants indicate their hand preference using checkmarks in columns:

• Left column only: Exclusive left-hand use
• Right column only: Exclusive right-hand use
• Both columns (one check each): Either hand used (no strong preference)
• Two checkmarks in one column: Strong preference for that hand

EHI-10 Activities

Fine Motor Activities:

1. Writing – Which hand do you use for writing?
2. Drawing – Which hand do you use when drawing?
3. Throwing – Which hand do you use to throw a ball?

Tool Use Activities:

1. Scissors – Which hand holds scissors when cutting?
2. Toothbrush – Which hand holds your toothbrush?
3. Knife (without fork) – Which hand holds a knife when cutting?
4. Spoon – Which hand holds a spoon when eating?

Complex Motor Activities:

1. Broom (upper hand) – Which hand is on top when sweeping?
2. Match (striking) – Which hand holds the match when lighting?
3. Box lid (opening) – Which hand opens a box lid?

Scoring System

Point Assignment for Each Activity:

• Two checks in right column: +2 points (strong right preference)
• One check in right column: +1 point (mild right preference)
• One check in each column: 0 points (no preference)
• One check in left column: -1 point (mild left preference)
• Two checks in left column: -2 points (strong left preference)

Laterality Quotient (LQ) Calculation

Formula: LQ = [(R – L) / (R + L)] × 100

Where:

• R = Sum of all positive (right-hand) points
• L = Absolute value of sum of all negative (left-hand) points
• LQ Range: -100 (strongly left-handed) to +100 (strongly right-handed)

Handedness Classification

Classification	Laterality Quotient (LQ)
Strong right-handed	+50 to +100
Mixed right-handed	+25 to +49
Ambidextrous	-24 to +24
Mixed left-handed	-25 to -49
Strong left-handed	-50 to -100

Population Distribution

• Right-handed (LQ > +25): Approximately 90% of population (Oldfield, 1971)
• Left-handed (LQ < -25): Approximately 8-10% of population (Oldfield, 1971)
• Mixed/Ambidextrous (LQ -24 to +24): Approximately 1-2% of population (Oldfield, 1971)

Interpretation Considerations

• Injury effects: Hand injuries may artificially shift reported preferences
• Strong preferences: Indicate consistent hemispheric dominance
• Mixed patterns: May suggest more bilateral brain organization
• Cultural influences: Some cultures historically discouraged left-hand use
• Developmental factors: Handedness typically stabilizes by age 3-4 years

Research Evidence and Psychometric Properties

Reliability Evidence

• Test-retest reliability: r = 0.97 over 6-month interval, demonstrating excellent temporal stability (Oldfield, 1971)
• Internal consistency: α = 0.94, indicating strong inter-item correlation (Oldfield, 1971)
• Split-half reliability: r = 0.92, showing consistency across item sets (Oldfield, 1971)
• Long-term stability: r = 0.89 over 10-year period in adults (Preti et al., 1997)

Validity Evidence

Concurrent validity:

• Observed hand use: r = 0.95 correlation with videotaped performance of activities (Oldfield, 1971)
• Performance measures: r = 0.87 with pegboard test laterality (Veale, 2014)
• Self-report consistency: r = 0.93 agreement across repeated administrations (Oldfield, 1971)

Construct validity:

• Factor structure: Single dominant handedness factor confirmed across cultures (Veale, 2014)
• Writing hand agreement: 98% concordance between EHI classification and self-reported writing hand (Oldfield, 1971)
• Throwing hand correlation: r = 0.91 with observed throwing hand preference (Oldfield, 1971)

Neuroimaging Correlations

• Language lateralization: Strong correlation (r = 0.78) with fMRI-determined language dominance (Knecht et al., 2000)
• Motor cortex asymmetry: Consistent with structural MRI measurements of motor cortex size (Amunts et al., 1996)
• Corpus callosum morphology: Relationships between handedness strength and callosal area (Witelson, 1985)
• Hemispheric activation: Correspondence with EEG and MEG lateralization patterns (Springer & Deutsch, 1998)

Genetic and Developmental Research

• Heritability: Estimated 25-30% genetic contribution to handedness determination (McManus, 2002)
• Family clustering: 20% left-handedness rate in children of two left-handed parents vs. 10% baseline (McManus et al., 2010)
• Twin concordance: Higher concordance in monozygotic (76%) vs. dizygotic (63%) twins (Medland et al., 2009)
• Developmental emergence: Handedness preferences stabilize by age 3-4 years (McManus et al., 2010)
• Prenatal factors: Associations with testosterone exposure and birth position (Geschwind & Galaburda, 1987)

Cross-Cultural Validation

• International samples: Validated in 40+ countries across six continents (Papadatou-Pastou et al., 2020)
• Cultural consistency: Left-handedness rates (7-10%) stable across cultures despite historical stigma (McManus et al., 2010)
• Translation equivalence: Factor structure maintained across 15+ language versions (Veale, 2014)
• Measurement invariance: Equivalent psychometric properties across cultural groups (Papadatou-Pastou et al., 2020)

Clinical Population Studies

• Stroke patients: Reliable classification of pre-morbid handedness (Bishop, 1990)
• Autism spectrum: Higher rates of mixed handedness (12-15%) compared to controls (Markou et al., 2017)
• Schizophrenia: Elevated mixed handedness prevalence (Dragovic & Hammond, 2005)
• Developmental disorders: Atypical lateralization patterns in dyslexia and ADHD (Geschwind & Galaburda, 1987)

Usage Guidelines and Applications

Primary Research Applications

• Neuroscience studies controlling for brain lateralization patterns
• Cognitive research examining language and spatial ability relationships
• Neuroimaging studies using handedness as predictor or control variable
• Developmental psychology tracking motor development and lateralization emergence
• Cross-cultural research investigating handedness prevalence across populations
• Genetic studies examining heritability and family patterns of lateralization

Clinical Assessment Uses

Neuropsychological evaluation:

• Establish dominant hemisphere for cognitive testing interpretation
• Baseline measurement before neuropsychological assessment battery
• Predict expected patterns of cognitive strengths and weaknesses

Pre-surgical planning:

• Language lateralization prediction for epilepsy surgery candidates
• Functional mapping support for tumor resection planning
• Risk assessment for language and motor deficits post-surgery

Rehabilitation planning:

• Stroke recovery protocols based on pre-morbid hand dominance
• Occupational therapy targeting appropriate hand for retraining
• Prosthetic fitting and training considerations

Research Design Considerations

Inclusion and exclusion criteria:

• Define handedness cutoffs clearly in protocols (e.g., LQ > +40 for right-handed)
• Consider whether to include or exclude ambidextrous participants
• Document any hand injury history that may affect results

Sample stratification:

• Account for 90:10 right-to-left handedness distribution
• Plan adequate sample size for left-handed subgroup analyses
• Consider matching groups on handedness when it’s a control variable

Statistical considerations:

• Use LQ as continuous variable when possible (more statistical power)
• Consider non-linear relationships with outcome variables
• Account for handedness-by-sex interactions in some cognitive domains

Administration Best Practices

• Activity demonstration: Show or mime activities if participant unclear
• Cultural adaptation: Ensure all activities are familiar in participant’s culture
• Multiple time points: Reassess in young children (under age 8) as preferences stabilize
• Family history: Consider collecting parental handedness for genetic studies
• Forced hand use: Ask about any childhood training to use right hand

Cross-Cultural Considerations

• Historical cohort effects: Older adults may show forced right-handedness from childhood training (Papadatou-Pastou et al., 2020)
• Cultural stigma: Some cultures historically discouraged left-hand use for eating or writing
• Activity relevance: Ensure all 10 activities are culturally familiar and practiced
• Translation quality: Use validated translations rather than ad hoc translation
• Interpretation caution: Consider cultural context when interpreting borderline classifications

Limitations and Cautions

• Self-report measure: Relies on accurate self-perception and memory
• Activity-specific: Handedness may vary by activity domain not fully captured
• Binary assumption: Assumes unidimensional left-right continuum
• Developmental changes: Handedness in young children (under 6) may still be developing
• Pathological left-handedness: Some left-handedness results from early right-hemisphere injury

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Legal and Copyright Information

Copyright and Usage Responsibility: Check that you have the proper rights and permissions to use this assessment tool in your research. This may include purchasing appropriate licenses, obtaining permissions from authors/copyright holders, or ensuring your usage falls within fair use guidelines.

The Edinburgh Handedness Inventory is free for research and clinical use. The original scale was published in an academic journal without commercial restrictions. Researchers and clinicians may use the measure without seeking specific permission, though proper citation of the original work is required.

Proper Attribution: When using or referencing this scale, cite the original development:

Oldfield, R. C. (1971). The assessment and analysis of handedness: The Edinburgh inventory. Neuropsychologia, 9(1), 97-113.

For the 10-item short form specifically, also cite:

Veale, J. F. (2014). Edinburgh Handedness Inventory – Short Form: A revised version based on confirmatory factor analysis. Laterality, 19(2), 164-177.

External Links and Resources

Handedness – Wikipedia

Brain Lateralization – Wikipedia

International Society for Laterality Research

Handedness Research Institute

References

Primary Development Citation:

• Oldfield, R. C. (1971). The assessment and analysis of handedness: The Edinburgh inventory. Neuropsychologia, 9(1), 97-113.

10-Item Short Form Validation:

• Veale, J. F. (2014). Edinburgh Handedness Inventory – Short Form: A revised version based on confirmatory factor analysis. Laterality, 19(2), 164-177.

Major Reviews and Meta-Analyses:

• Papadatou-Pastou, M., Ntolka, E., Schmitz, J., Martin, M., Munafò, M. R., Ocklenburg, S., & Paracchini, S. (2020). Human handedness: A meta-analysis. Psychological Bulletin, 146(6), 481-524.
• McManus, I. C., Davison, A., & Armour, J. A. (2013). Multilocus genetic models of handedness closely resemble single-locus models in explaining family data and are compatible with genome-wide association studies. Annals of the New York Academy of Sciences, 1288(1), 48-58.

Neuroimaging and Brain Lateralization:

• Knecht, S., Dräger, B., Deppe, M., Bobe, L., Lohmann, H., Flöel, A., Ringelstein, E. B., & Henningsen, H. (2000). Handedness and hemispheric language dominance in healthy humans. Brain, 123(12), 2512-2518.
• Amunts, K., Schlaug, G., Schleicher, A., Steinmetz, H., Dabringhaus, A., Roland, P. E., & Zilles, K. (1996). Asymmetry in the human motor cortex and handedness. NeuroImage, 4(3), 216-222.

Genetics and Development:

• McManus, I. C., Moore, J., Freegard, M., & Rawles, R. (2010). Science in the making: Right hand, left hand. III: Estimating historical rates of left-handedness. Laterality, 15(1-2), 186-208.
• Medland, S. E., Duffy, D. L., Wright, M. J., Geffen, G. M., Hay, D. A., Levy, F., van-Beijsterveldt, C. E., Willemsen, G., Townsend, G. C., White, V., Hewitt, A. W., Mackey, D. A., Bailey, J. M., Slutske, W. S., Nyholt, D. R., Treloar, S. A., Martin, N. G., & Boomsma, D. I. (2009). Genetic influences on handedness: Data from 25,732 Australian and Dutch twin families. Neuropsychologia, 47(2), 330-337.

Clinical Applications:

• Bishop, D. V. (1990). Handedness and developmental disorder. Blackwell Scientific Publications.
• Markou, P., Ahtam, B., & Papadatou-Pastou, M. (2017). Elevated levels of atypical handedness in autism: Meta-analyses. Neuropsychology Review, 27(3), 258-283.