Usability engineering (UE)—or human factors engineering (HFE) focuses on designing a user interface (UI) that allows people to quickly understand how to interact with a Medical Device (MD) in the most efficient and error-free manner. It supports the development of safe and effective medical design, by identifying and appropriately mitigating risks associated with usability.
In this regard, regulatory bodies have established a set of regulations and standards to help guide medical device manufacturers through the usability engineering process.
Let’s focus on one of the most important of those standards “IEC/EN 62366.”
What is the IEC/EN 62366 standard?
IEC/EN 62366 is an international standard which specifies a process for a manufacturer to analyse, specify, develop and evaluate the usability of a medical device as it relates to safety. This usability engineering process permits the manufacturer to assess and mitigate risks associated with correct use and user errors, i.e., normal use.
IEC/EN 62366 is a process-based standard that aims to help manufacturers to design efficient medical devices.
IEC/EN 62366 is divided into two parts:
- IEC/EN 62366-1:2015— Application of usability engineering to medical devices.
- IEC/TR 62366-2:2016— Guidance on the application of usability to engineering to medical devices.
IEC/TR 62366-2 is a technical report which contains background information and provides guidance on implementing IEC 62366-1. This technical report is not intended to be used for regulatory purposes. It contains no requirements and only provides guidance and tutorial information.
Both of standards are recognized consensus standards by US FDA and “Declaration of Conformity” from a medical device manufacturer to satisfy part of a premarket review requirement will be accepted by FDA. Additionally, FDA Guidance for Applying Human Factors and Usability Engineering to Medical Devices is suggested for premarket review. This guidance document is intended to support manufacturers in improving the design of devices to minimize potential use errors and resulting harm and to enable manufacturers to assess and reduce risks associated with medical device use.
What are the process steps of Usability engineering (UE) or human factors engineering (HFE)?
The results, information and records generated from the HFE/UE process shall be maintained within the HFE/UE File in accordance with IEC/EN 62366-1. The steps involved in the HFE/UE Process are outlined below:
- Prepare Use Specification
- Identify User Interface Characteristics related to Safety and Potential Use Errors
- Identify known or foreseeable Hazards and Hazardous Situations
- Identify and Describe Hazard related Use Scenarios
- Select the Hazard related Use Scenarios for Summative Evaluation
- Establish User Interface Specification
- Establish User Interface Specification Plan
- Perform User Interface Design, implementation, and Formative Evaluation
- Perform Summative Evaluation of the Usability of the User
- User interface of Unknown Provenance
Usability engineering validation
Usability engineering validation of devices is performed in two ways, formative evaluation and summative evaluation:
1.Formative Evaluation and Reporting
Formative evaluation can support medical device concept development, refinement and various types of design decisions. Formative evaluations usually include tasks or hazard related use scenarios in which use errors could occur and help to determine if the risk controls designed into the medical device have been successful.
Formative Evaluation Protocol shall be prepared to evaluate to methods being used, which part of the user interface is being evaluated and when in the usability engineering process to perform each of the user interface. The main objective of the protocol shall be to collect data which can include:
a) customer preference survey responses,
b) focus group participants’ inputs (i.e., comments),
c) usability test participants’ comments, made while performing hands-on tasks as well as upon reflection on their task performance afterward, and
d) usability test participants’ ratings and rankings pertaining to hands-on tasks, specific medical device characteristics and the medical device in general.
Results shall be documented in Formative Evaluation Report supported by raw and processed data sets (e.g. a spread sheet containing Task performance data) and, if collected, video recordings and photographs of the test sessions. Design shortcomings identified during testing shall be formally tracked to ensure they are resolved and re-evaluated as needed according to the Design and Development Procedure.
2.Summative Evaluation and Reporting
Summative evaluation generally involves performing a usability test under conditions of simulated use.
Summative Evaluation Protocol shall define clearly test participants, hands-on tasks associated with the selected hazard-related use scenarios and test environments.
Usability test data collected during a summative evaluation shall include:
a) task completion (and, where related to safety, time to complete),
b) descriptions of observed use errors, close calls and use difficulties,
c) participants’ comments (e.g. anecdotal remarks) about their medical device interactions, and
d) participants’ reported root causes of their use errors and close calls.
The summative evaluation data shall allow a conclusion for the adequacy of the user interface. The outputs of the summative evaluation shall be evaluated in the risk management process to determine whether the residual risks related to usability are acceptable.
Summative evaluation results shall be documented in Summative Evaluation Report supported by raw and processed data sets. The outputs of this report shall be used to improve the user interface according to the Design and Development Procedure.
When usability engineering is performed properly, it provides many benefits for users, patients and medical device manufacturers. Devices become easier to use, reducing the risk of misuse, adverse events, and product recalls.
If you have difficulty preparing your usability engineering file, please contact us. Our experts will be happy to assist you.