Ensuring Accessibility for all Users Through Rigorous Acoustic Testing
The YpsoMate autoinjectors address a multitude of different user groups and Ypsomed ensures that the devices are accessible to all people including those with visual or hearing impairments. Therefore, the acoustic characteristics of the devices are examined in an anechoic chamber at METAS, the Swiss Institute of Metrology.
YpsoMate is the injection platform for automated injections based on prefilled syringes.
YpsoMate 1mL and 2.25mL versions are used for a broad range of indications and diverse patient populations every day.
According to the Vision Loss Expert Group 253 million people worldwide are visually impaired (see here). With a growing market for medications delivered via autoinjectors, it is mandatory to ensure accessibility of our devices for all potential users.
The requirements
The ISO 11608-7, which specifies requirements to “make needle-based injection systems accessible for people with visual impairments”, states that the information for safe use of the autoinjector shall be perceptible to users with moderate visual impairment and that users with blindness shall be able to access the same information by non-visual means.
The YpsoMate autoinjector provides two independent clicks to inform the user about the progression of the injection. Naturally these clicks shall be perceptible against environmental noises even if the user may have some form of hearing loss.
Loudness – the human factor
Physically the sound emitted by a source can be specified in an objective way by the sound power. This sound power is independent of the surroundings of their source and raises the sound pressure level in the environment.
But the human ear is not equally sensitive to sounds of the same sound pressure and the subjective magnitude of a sound is dependent on its frequency. Most sensitive is in the range of 3-4 kHz and less so on the lower and upper end of the audible spectrum.
This human peculiarity is addressed by different weighting factors which can be applied to recorded sound pressure levels. A-weighting, which is one of the most common scales applied and used at Ypsomed to evaluate the loudness of YpsoMate devices, weighs sound pressure levels approximately in accordance with the frequency response characteristics of the human ear.
To measure the sound pressure of our devices, Ypsomed collaborates with METAS, the Swiss Institute of Metrology. Since reflections of the sounds influence the end results, the tests are carried out in an anechoic chamber, the walls of which are covered in a sound-absorbing foam.
In the anechoic chamber at METAS, the YpsoMate devices are tested using a fixture which was designed by Ypsomed. The fixture allows YpsoMate activation with nominal interference by the person conducting the test. During the test the activation of multiple autoinjectors is recorded and later evaluated against specific criteria.
The criteria which Ypsomed tests for were set on a theoretical basis according to information from respective literature, considering common environmental noises and values from ISO 24501, which defines sound pressure levels of auditory signals. The acceptance criteria in the conducted tests were thus set to 55 dB(A).
The tests were conducted for the YpsoMate 1mL and 2.25mL platform products and the results showed a minimal sound pressure level of around 64 dB(A) for both product platforms, taking into account statistical tolerance bounds.
These results are about 10 db(A) higher than the set acceptance criteria. To give this number a more ‘hands-on’ meaning consider the following remark. According to common literature an increase of the sound pressure by 10 dB(A) is perceived by humans as a twofold increase in the loudness of the acoustic event.
The above ensures that most people with visual and hearing impairments can perceive the signals emitted by the YpsoMate devices. This way ensuring accessibility for all patient groups.
Patrick Poenitsch
Patrick Poenitsch works as Development Engineer on the YpsoMate 2.25ml platform at Ypsomed Delivery Systems. He has been with Ypsomed since 2021. Mr. Poenitsch holds an MSc in Mechanical Engineering from TU Ilmenau. He has 6 years' experience across different positions in the fields of mechatronics, mechanical and test engineering and 4 years of experience in the medical device industry.
Stay tuned, stay informed
Subscribe to the Ypsomed Blog and join our journey to simpler and easier selfcare.
