My Concerns With the EASI Sensory Integration Assessment Materials and Use of 3D Printed Pieces


7-16-21: Thank you to Dr. Zoe Mailloux for responding to my concerns and clarifying some inaccuracies which had been included in my original blog post. Here is a summary of her response:

The EASI consists of 20 tests that evaluate sensory perception, sensory reactivity, motor skills, and praxis. The 3D printed forms are specifically required for 2 tactile discrimination tests. A major purpose of the EASI is to make comprehensive assessment of sensory integration functions more accessible and affordable. Since EASI is not owned by any for-profit business or entity, there are some cost savings compared to acquiring the test materials through a publisher. In fact, most of the EASI test materials can be purchased at regular stores and some can come from recycled materials, which addresses some environmental considerations.
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3D printing allows for a cost-effective method for the production of novel shapes that are unfamiliar to children worldwide. The EASI 3D Printing Coordination Team has established a list of verified printers and shapes can only be obtained from them (i.e. EASI shapes are not currently  available for self-printing.) The plastics used are verified as non-toxic and the oral shapes are food grade plastic. Cleaning procedures for the shapes are provided and have been reviewed and approved by public health officials. Test sheets, forms, and the manual will be available without fees for qualified testers and mechanisms have been added to ensure consistency of the paper used in different countries.
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The EASI team is committed to environmental responsibility and the test sheets and manual will be made available digitally with an online scoring program to eliminate the need for paper to allow for a fully digital method. If forms are to be used, techniques will be suggested to allow multiple uses of forms. Overall, the EASI will be a low-cost, accessible set of tests that are being made possible by the efforts of volunteers around the globe. Their unifying theme is “Children Understood”. You can find out more about the EASI and their effort at

About the EASI – Evaluation In Ayres Sensory Integration®

The EASI has an interesting approach to their new Sensory Integration assessment tool. This is supposed to be the new assessment and successor for the SIPT, which many critics say is outdated. SIPT certification is paused. [1]

The use of 3D printed pieces is intended to promote accessibility of the testing materials combined with other easy-to-purchase items that should be available worldwide (that is nice). [2] I believe this is a very creative approach to solving the problem of accessibility, distribution, and the high cost of testing materials.

The EASI uses 3D printed Pieces Source:

The Evaluation of Ayres Sensory Integration (EASI) Tactile Perception contains tests that will use 3D printed materials. [3]

Shapes, Oral (TP:SO) Tactile Perception: Shapes, Oral (TP:SO)

    • One set of 12 items: all made with clear filament

Shapes, Part I (TP:S1) : Tactile Perception: Shapes, Part I (TP:S1) Two sets of shapes each:

    • one complete set of 12 shapes (including two distractors) with black filament
    • one complete set of 10 shapes with blue filament

Shapes, Part II (TP:S2) Tactile Perception: Shapes, Part II (TP:S2). Two sets of shapes each:

    • one complete set of 17 shapes (including two distractors) with green filament
    • one complete set of 14 shapes with yellow/orange filament

However, there are many problems I see with using 3D printed pieces in the EASI, if they are to be included in the finalized assessment and are norm-referenced with good reliability and validity.

On the surface, using 3D printed pieces has good face validity, but I am skeptical of the more rigorous statistical measures such as reliability and construct validity.

About Standardization

For a test to be standardized, the materials used by each researchers and the test taker needs to the same or identical. Non-commercial 3D printing is still considered in its beta stages for hobbyists. There can be a lot of variability in the 3D printing process, such as the method in which the piece is laid out to the type of material chosen. This is the physical and hardware side. Then there’s the software. Unless everyone uses the same piece of software and print settings, the 3D piece that is created is not going to be ‘identical’.

Examples of some settings:

  • Temperature
  • Layer height
  • Speed
  • Retraction
  • Flow
  • Adhesion assistance
  • Supports
  • Cooling
  • Infill
  • Shell thickness

There are too many variables for the novice user from the software side to the hardware to the materials that they’re not going to come out the same. So a piece that is intended to be a star shape may look like it, but unless you compare it to a master template, you will never know if it is standardized. It might not even weigh the same.

Characteristics of 3d Printed Materials

  • Weight
  • Shape
  • Density
  • Color
  • Flexibility/Strength
  • Durability
  • Texture
  • Heat resistance

As an analogy, if you are making a homemade greeting card that is intended to be identical to a commercially available one, e.g., Hallmark card. Unless you are a professional greeting card manufacturer, in a blinded test, many would be able to point out which one is commercial and which one you made – because you don’t have the same professional paper stock, inks, printer, printing process, and whatever else goes into the process. The same applies here, unless you have the same 3D printer, with the same filament, using the same 3D model file (assuming it does not get corrupted in the download process (CRC checked for file integrity), using the same software (and the same version of the software on the same operating system), in the same temperature environment of production, with the same exact print settings, there’s going to be some variation and that is not standardized.

3D Printing is Not Really That Accessible

3D printing is becoming more accessible. You can go online, purchase a 3d printer, buy some filament, hook it all up, and away you go. However, I doubt many occupational therapists have a 3D printer available. Yes, I know many hobbyist and early adopters are doing awesome things with 3D printing from making widgets for adaptive equipment, splints, to functional prosthetics. But this is the exception more than the norm. It requires a learning curve, lots of experimentation, and a lot of patience.

One could say you can use a 3D commercial company, e.g., you send them the model file and they print it for you. As they are professionals and may make a better-looking 3D printed piece, there is still the issue of standardization. You don’t know what 3D printer they use, the environment it is in, etc. Unless everyone uses the same company to print their 3D pieces for their EASI testing materials, this is not standardized.

3D Printed Pieces are Not All Stable

3D printed pieces can melt, depending on the type of filament used. I have seen this happen as I left a 3D piece of those ear guards for face masks during the pandemic in my car on a hot day and came back to find it warped and basically melted like an airhead candy.

Some materials will be more durable than others. If EASI is to allow 3d printed pieces in their final assessment, they need to at least make requirements for the type of filament used, e.g. not PLA. You may be thinking, well, who leaves testing materials in their car exposed to the heat? Well, many home health occupational therapists who go between clinics or provide this assessment in the client’s home could potentially run into this issue.

3D Printing Process Can Be Dangerous to Your Health

3D printing fumes can be dangerous to your safety and health. The 3D printing process produces emissions in the form of toxic filament fumes. [4] The question then is, are these materials all safe to handle for the test administrators and for the children being tested? I would not want my child touching BPA for an OT assessment. The BPA plastic controversy has brought more awareness to how some plastics may be harmful to our health. I wonder if printed pieces continue to release toxic VOCs. More ongoing research is being conducted to study the effect of other plastics on human health. What about the plastics or materials used in the EASI 3d printed pieces?

Plastics Are Not Good for the Environment

Whether you care about this issue or not, plastics are certainly not good for our environment and for the animals living around plastic waste. “Plastic materials are predominantly not biodegradable and having a low density makes them unfit for disposal in landfills.” [5]Aguado, D.P. Serano, G.San Miguel, 2007European Trends In, The Feedstock Recycling of Plastic Wastes, Global NEST Journal, 9-10, Pp. 12-19. From a ‘green’ standpoint, we have an ethical responsibility to find ways to manufacturer, use, and recycle plastics to protect our planet. The process and use of these 3D printed may contribute to the plastics problem. Hopefully we see alternative materials, e.g., such as plant-based filaments come out and become assessible. But at the end of the day, plastic is going to be cheaper than more greener materials. And the whole point of 3D printing, one would argue is accessibility and affordability.

Infection Control

Assessment materials may be infection mediums. When JCAHO came around to our hospital, we had to throw away so much stuff. And this was before COVID-19. While plastic is likely a better material for infection control compared to more porous surfaces, not all 3d printing is the same, and some of it may still be somewhat porous. This can allow bacteria and viruses to breed in these materials and contribute to infectious diseases. Let’s take a look at the other materials proposed in the EASI:

EASI Materials
– Solid color, plain cloth napkin (1)
– Pipe cleaners (2)
– Cotton balls (2)
– Empty plastic bottle (“Rice Bottle”) (1)
– Small plastic cups (12)
– Metal pen (1)
– 6-pack carriers (2)
– Small paint brushes (2)
– Dog “clicker” (1)
– Square wooden block (1 inch) (1)*
– White cardstock (5)
– Green cardstock (2)
– Yellow cardstock (2)
– Red cardstock (2)
– Business card magnets (5)
– 3D printed shapes – black (12)
– 3D printed shapes – blue (10)
– 3D printed shapes – yellow (14)
– 3D printed shapes – green (17)
– 3D printed shapes – white oral plus black nuts (12) [6]
*About wood: our facility even had to get rid of our wooden slideboards and replace them with plastic ones for infection control due to the potential for the surface to be porous.


Items that are at high risk for infection are highlighted in red. Sure, test administrators and test takers can wash their hands, but how long should these materials be used before being replaced? And what is the research behind the duration of use? This is an important area that should be more researched.
Scientists from the University of Sheffield have integrated antibacterial properties into polymer powders to create 3D printed parts capable of fighting infectious diseases. [7]

The price was listed as $175. You can purchase some of these materials at ‘Dollar Stores’. However, this no longer makes the test standardized. For example, for the colored cardstock, there could be variations in color, paper weight, brightness, etc.

OT as a Green Steward

I believe occupational therapy has an equal responsibility to its use and contribution to waste. That is why I am not a major fan of recommending adaptive equipment in general to clients unless absolutely necessary, because they end up being neglected just thrown away and ending up in our landfills.


I am not against 3D printing. I am not against providing accessibility of testing materials and make it “open-access”. I am not against adaptive equipment. The EASI is a step in the right direction as a replacement for the SIPT (which was the gold standard but has outdated referenced norms ).

What I am concerned about the EASI doing is that it may end up setting a trend for future OT assessments. Especially since they are involving the international OT community to norm reference their data to be generalized to specific populations. Hopefully, the same test materials are used around the world during this crucial initial research phase in the making of the assessment.

As responsible stewards and ethical practitioners, we should ensure that testing materials are standardized, safe for the environment, the person printing it, the test taker handling it, and its disposal. There should also be a consideration in the choice of materials for infection control and recommended lifespan of such materials based on exposures, e.g., a confirmed COVID-19 patient touched this cotton ball.

Advancements in technology will play a large role in our lives and we are seeing it being used in occupational therapy from virtual reality to Apps to AI to 3d printing. However, for an assessment that will be used worldwide, much more research needs to be done in the use of its testing materials that are intended to be made “open-access” or open-source.


  • Recommend use of ‘greener’ 3d printing.
  • OTs should consult with and work with 3d printing industry to make to follow the universal design, reduce harm to humans and the planet, and promote accessibility in line with assistive technology approaches.
  • Create a standard for materials, process, environment, software, etc. in the production of 3d printed pieces. The pieces should be weighed to ensure uniformity to the ‘standard’.
  • Create a list of materials, hardware, software, and methods to avoid as research supports its harm and threats to statistical rigor.
  • Conduct research into the feasibility, reliability, and validity of these materials for a ‘standardized’ assessment.
  • Provide guidelines on the disposal of exposed testing materials and recommendations for their lifespan for infection control and the safety of our occupational therapy clinicians, clients, and their caregivers.
I look forward to learning about the developments in the EASI, especially with its approach to worldwide volunteer efforts in contributing to the research, translation, and future use in other countries.