This Literature Review answered the three primary questions: What Assistive Device to make?, Which Design Methodology to implement? and finally, Which 3D-Printing technique to use? by reviewing a wide range of scholarly articles, case studies, technical advancements and research papers on Cognitive Impairments, Design Methodologies, and 3D-printing technologies respectively.

Observations:

• Cognitive Impairments: Essential Tremor (ET) is the most common side effect of cognitive impairment, specifically from mild stage to dementia. This discovery prompted the choice of Essential Tremor as the target area due to its enormous market and prevalence of over a million people suffering alone in the UK. Therefore, the creation of Assistive Device that is especially made for people with Essential Tremors (ET) was then made.
• Design Methodologies: After evaluating various design methodologies like Participatory Design Methodology, Inclusive Design Methodology, and User-Centric Design Methodology. It was concluded that The User-Centric Design Methodology will be used as the design approach in this scenario. As will put the end-user’s usability, preferences, and needs first, resulting in a solution that effectively meets their needs.
• 3D-Printing: After weighing the pros and cons of each 3D Printing Technique available it was found that the Selective Laser Sintering (SLS) was a suitable manufacturing process due to its high precision, exceptional durability, and capacity to create complex shapes.

Conclusion:

Finally, the conclusion drawn from the Literature review to design and develop an Assistive Device for Essential Tremors (ET) using User-Centric Design Methodology and manufactured by Selective Laser Sintering (SLS) 3D-Printing.

The Market Research is aimed to investigate pre-existing assistive technologies/devices on the market to discover the market gaps that current solutions leave unfilled. This will help to consolidate the Unique Selling Proposition (USP) using insights gained from comprehensive analyses and will use this as a framework for developing our Product Design Specifications (PDS) which will be the basis of the product development for our assistive device.

Types of Assistive Devices Available in the Market

• Electrical Stimulation Systems
• Wearable Orthoses
• Assistive Feeding Devices
• Haptic Stimulation Systems

Here, Electrical Stimulation Systems, Wearable Orthoses, and Haptic Stimulation Systems all focus on the neurological side to reduce tremors. However, we are currently interested in the mechanical Assistive Devices; hence, Assistive Feeding Devices are important for our market research.

Assistive Feeding Devices

• Neater Eaters: Neater Eaters allow people to feed themselves by moving around. Neater Eaters are simple to use and filled with functions and attachments to accommodate users of all abilities and needs. The Neater Eater promotes mealtime independence, social connection, and an interest in food and nutrition. Both the user and the caregiver benefit from the Neater Eater.

• Liftware Spoon: Liftware consists of an electrical stabilizing handle and a variety of attachments such as a soup spoon, daily spoon, fork, and spork. Liftware Steady is intended to make eating easier for persons who have hand tremors caused by Parkinson's disease or essential tremor.

• Gyenno Spoon: The Gyenno Spoon is similar to Liftware and have simailar attachment and functionality

Market Gap

• Poratble: Unlike Liftware and Gyenno Spoon, Neater Eater lacks portability. They require external support for transportation. This identifies a significant market gap to design a lightweight, compact device, that will enhance mobility and user autonomy.


• Modularity and Compatibility with Standard Cutlery: All assistive devices are restricted to proprietary cutlery, limiting their versatility. This highlights the market gap to design a modular system compatible with standard household utensils. This adaptability will ensure seamless integration into the user's everyday environment, enhancing usability and practicality.


• Energy Efficiency and Battery Replacement Flexibility: Recognizing the limitations of current devices that rely heavily on internal rechargeable batteries, which opens a market gap to feature user-replaceable battery modules, allowing for easy and flexible battery replacement. This ensures uninterrupted operation and greater convenience for the user.

The Product Design Specification (PDS) is a cornerstone document that guides the entire design and development process. It acts as a dynamic blueprint, evolving and adapting as the project progresses and is subjected to updates and revisions throughout the design process, ensuring that the final product not only meets but exceeds the initial expectations and requirements. After the design activity, the device is expected to align seamlessly with the specifications outlined in the PDS, reflecting the evolution and refinement of the product from concept to reality.

Permormance Design Specifications

This section details the functional requirements and performance criteria the device must meet, focusing on its efficacy in assisting individuals with Essential Tremors.

Material Design Specifications

This section details materials chosen for their durability, safety, and suitability for the intended use of the device, ensuring a balance between quality and cost-effectiveness.

Dependability Design Specifications

This part emphasizes the reliability and longevity of the device, ensuring it consistently performs as intended over time.

Saftey Design Specifications

This crucial section addresses the safety standards the product adheres to, prioritizing the well-being and security of its users.