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Prevent Self Harm in patients with Autism Spectrum Disorder

Problem Description

When patients with Autism Spectrum Disorder (ASD) and other developmental disorders are agitated or in a panicked state, many end up harming themselves by biting or scratching their arms as a coping mechanism. Parents of children with these conditions struggle to prevent this behavior as they get older and physically stronger. Current devices to prevent biting do not protect the full-arm or are simply not feasible to wear for prolonged periods. We believe that finding a way to prevent these patients from self-harming while still being able to bite and scratch themselves as a coping mechanism is a serious need that should be addressed.

My Contribution

As a part of the team, I worked with the FDA quality system regulation (QSR) with emphasis on the Design Controls (21 CFR 820.30).  The Specific experience includes ethnography and human factor analysis, formulation of technical specifications, failure mode, and effects analysis (FMEA), verification and validation (V&V) planning. One of the interesting Verification protocols I developed the drying rate protocol. to test the drying of the sleeve we designed. 

I also gained experience Experience with the formulation of a comprehensive Design History File (DHF).

Hazard and Risk Analysis:

 

Hazards and risks were identified by looking at known risks of existing designs and hazards associated with protective equipment. Ten hazards were identified, each with quantifiable severity, potential causes, probability of harm due to cause, risk, possible control measures, and adjusted risk. Identified hazards were: strangulation, choking, dislocation or muscle strain, skin irritation or contact dermatitis, allergic reactions, blood flow restriction to extremities, acute skin abrasion, non-acute skin abrasion, damage to teeth, mouth, or face, and patient injures themselves or caretaker due to emotional distress.

Based on the hazard’s risk and probability of severity, changes to the design were made to ensure a better and safer product. Changes included using a tighter woven material as the outer layer, industrial stitching at seams, and using elastic straps.

Final Design:

 

The current design is a sleeve made of two layers of Kevlar, a neoprene and silicone rubber middle layer for added protection, and an inner layer of a cotton/spandex blend fabric. Sleeves were designed to have an elbow hole and a thumb hole. Both sleeves are connected by an elastic strap with a buckle on the back. Figure 1A features the material composition and arrangement of the device. Figure 1B and Figure 1C show the back and wrist securement respectivefully.

 

Verification and Validation Results:

 

Four verification tests were performed to assess the device’s ability to withstand baseline safety and effectiveness for use. The tests performed were Puncture Assessment, Machine Washability Assessment, Abrasion Resistance Assessment, and Durability Assessment. Results from each verification study are summarized as follows:

 

  • Puncture Assessment: The device can withstand high forces and high pressures that are above the range of an average bite.
  • Machine Washibility Assessment: The device should be washed by hand only. The device should be left to air dry for at least 12 hours after washing.
  • Abrasion Resistance Assessment: Both layers of Kevlar were fully abraded at extreme conditions. However, the device could be expected to not deteriorate from daily wear and tear easily.
  • Durability Assessment:  The first layer of Kevlar was fully abraded by the end of the first or second run. The device failed the acceptance criteria, but the protocol needs to be adjusted to accurately represent everyday wear and tear.

 

In summary, verification studies revealed that the device is highly protective from puncture and abrasion, but fails to be machine washable. While the device needs modifications to the design to better meet user needs, validation studies revealed that there is a general satisfaction with the device. Slight concerns were identified regarding the breathability and thickness of the device, but responses showed high satisfaction with the protective abilities of the sleeves. Overall, the device is, at best, satisfactory to customer needs, but needs modifications to the design and manufacturing process so that the device

 

Unmet Need Identification:

 

In early September, the first steps our team took in identifying unmet clinical needs was looking into our own experiences and the different problems we have encountered. A list of roughly 15 ideas for clinical unmet needs was identified. We then reached out to individuals who may be more knowledgeable or experienced in the issues we were trying to address. On September 25, Shawn Danhouser, a parent and a soccer coach for children with special needs, provided us with feedback that helped us identify the need for protective equipment to prevent self-injurious behavior in individuals with Autism Spectrum Disorder (ASD).

 

After identifying this unmet need, we developed a survey inquiring about self-injurious behavior in patients with ASD. Questions included frequency of biting, severity of injuries, if they use any protective devices, and any anecdotal experiences they were willing to share. From our survey, 35% of the responses said that they know someone who bites or scratches themselves as a coping mechanism, 50% of which leave open wounds. The majority of surveyors said that there is a medium to high frequency of self-harming behavior. This preliminary ethnographic data validated Shawn Danhouser’s claim of this unmet clinical need as a widespread issue. Therefore, we decided to pursue this as the foundation of our Senior Design project.

 

Design Inputs:

 

Through the identification of user needs, the killer experiments, and input from experts, we defined the following design inputs:

  • Size: The device should have an upper arm length adjustable between 20-40 cm and an adjustable circumference.
  • Maintenance and Cleaning: Washable using a machine washer and dryer. Can be washed with detergent and warm water
  • Materials: 
    • Outer layer: Kevlar
    • Middle layer: Neoprene and silicone rubber
    • Inner Layer: Spandex fabric
    • Fastening mechanism: plastic lock with elastic strap
    • Should not have materials that cause skin irritation and allergic reactions; no sharp projections.
  • Weight: 2 pounds maximum
  • Product Life: 3-5 years
  • Packaging: Our device will be sealed in plastic film and shipped in a cardboard box with a volume less than 12 inches cubed.
  • Labeling: Should be on the outside of the product using a straight cut/flat label or loop fold. Should contain following information: size, care/cleaning instructions, material information, brand name. 
  • Usability: Device should be slipped on in less than a minute by parent/caregiver.
  • Durability: Device should be able to protect from puncture and pressure wounds caused by a pressure of 1.75 Newtons/cm2 from the front incisors.