Edinburgh Handedness Inventory (EHI)

Purpose

The Edinburgh Handedness Inventory (EHI), sometimes referred to as the Edinburgh Handedness Questionnaire (EHQ), was developed by Richard Charles Oldfield to objectively ascertain the handedness of a subject in activities of daily living (ADL).[1] It is the most commonly used screening tool for handedness.[2][3]

Intended population

It has been used in a wide variety of subjects ranging from children with autism to adults with stroke.[2][3]

Method of Use

There is controversy surrounding its use due to the existence of multiple variations of the tool and improper understanding of the original test instructions.[2][4] The older 20-item questionnaire contains instructions to be strictly followed during administration. Items are rated either by direct observation or by self-report.[1] A more commonly used, shorter 10-item version was developed to overcome sociocultural differences that affected the relevance of certain items which limited its universal use.[1][3]

The original 20 items are:

  1. Writing
  2. Drawing
  3. Throwing
  4. Scissors
  5. Comb
  6. Toothbrush
  7. Knife (without fork)
  8. Spoon
  9. Hammer
  10. Screwdriver
  11. Tennis racket
  12. Knife with fork
  13. Cricket bat
  14. Golf club
  15. Broom
  16. Rake
  17. Striking a match
  18. Opening a box (lid)
  19. Dealing cards
  20. Threading a needle

From the above, items 1, 2, 3, 4, 6, 7, 8, 15, 17, and 18 made it into the ubiquitous 10-item version of the EHI.[1]

Scoring

For each of the items, the subject is asked to specify the side they prefer to perform the given activity (self-rated method), alternatively, the subjects can be made to perform the said activity and the observer can rate the findings (direct observation method). [Refer to the following document: https://rhd.talkbank.org/protocol/handedness.pdf]

If the preference is for either the left or the right side, then a "+" is marked on the column for that side.

If the preference for a particular side is so strong that one wouldn't use the other side unless forced, then a "++" is marked on that side.

If there is no preference for any side, then a "+" is marked on both sides.

For items that involve a bimanual task such as striking a match, the hand involved in the usage of the key item (i.e. the match) is considered as the preferred side.

If the subject has no experience of any given task, then that item remains unmarked.

The final score is called the "Laterality Quotient". It is calculated using the formula:

Laterality Quotient = (R-L)/(R+L) X 100

Here, R & L refer to the total number of "+" marked on the right and left side respectively.

The Laterality Quotient value is used to interpret handedness as given below:

  • Left-handedness = Less than -40
  • Ambidexterity = Between -40 and +40
  • Right-handedness = More than +40

Psychometrics

According to Oldfield, results from a self-reported EHI yield less reliable results since subjects usually overestimate the number of tasks carried out by the dominant hand.[1]

References

  1. 1.0 1.1 1.2 1.3 1.4 Oldfield RC. The assessment and analysis of handedness: The Edinburgh inventory. Neuropsychologia. 1971; 9: 97-113.
  2. 2.0 2.1 2.2 Edlin JM, Leppanen ML, Fain RJ, Hackländer RP, Hanaver-Torrez SD, Lyle KB. On the use (and misuse?) of the Edinburgh Handedness Inventory. Brain Cogn. 2015 Mar;94:44-51. doi: 10.1016/j.bandc.2015.01.003.
  3. 3.0 3.1 3.2 Caplan B., Mendoza JE. Edinburgh Handedness Inventory. In: Kreutzer JS, DeLuca J, Caplan B (eds) Encyclopedia of Clinical Neuropsychology. 2011; Springer: New York, NY. https://doi.org/10.1007/978-0-387-79948-3_684
  4. Fazio R, Coenen C, Denney RL. The original instructions for the Edinburgh Handedness Inventory are misunderstood by a majority of participants. Laterality. 2012;17(1):70-7. doi: 10.1080/1357650X.2010.532801.