The use of mobile health applications is increasingly common among the general public and in healthcare systems. With such apps percolating into the classic healthcare sector, the necessity of sound and standardized evaluation grows. The mHealth App Usability Questionnaire (MAUQ) provides a novel and custom-tailored psychometrically validated instrument to capture users’ perception of the usefulness and usability of an mHealth application. So far, this questionnaire is only available in English, Malay and Chinese. The aim of this study was to translate and validate a German version of the MAUQ (G-MAUQ). Further, we developed a short scale with 6 items (G-MAUQ-S) in German.
We used the Translation, Review, Adjudication, Pretest and Documentation (TRAPD) method to translate the MAUQ. Subsequently, we assessed content validity with 15 expert ratings and face validity with 15 German speaking mHealth users. To further validate the questionnaire, we used data from 148 participants of an RCT examining symptom checkers in the Emergency Department to assess convergent validity by correlating the G-MAUQ with the German version of the System Usability Scale and discriminant validity by correlating the G-MAUQ with other unrelated questionnaires. Lastly, we developed a short version by assessing item discrimination, factor loadings, correlation with the full scale and construct validity.
All but one item showed sufficient content validity with item-level content validity index values between CVI-I = 0.8 and 1.0. Face validity was excellent with item-level face validity index values ranging from FVI-I = 0.87 to 1. Convergent validity was sufficient with r = 0.769, and discriminant validity was sufficient with values between r = −0.014 and r = 0.220. An internal consistency of Cronbach's α = 0.93 demonstrated high reliability. The short scale showed sufficient convergent validity (r = 0.762) and discriminant validity (r between −0.012 and 0.201).
A validated and reliable G-MAUQ can be used by researchers and practitioners to assess the usability of mHealth interventions. We also provide the German mHealth App Usability Questionnaire – Short Version (G-MAUQ-S) with six questions to quickly assess the usability of an intervention.
The gait of a subject follows a specific pattern, but variations exist that are unique to a subject but contrasting to other subjects. This can be utilized for biometric authentication to prevent impersonation during gait studies. However, due to the dynamic nature of gait, like changes in gait speed while walking, gait biometric authentications are challenging. In the state-of-the-art, although attempts have been made to use deep learning and other signal processing methods for biometric authentication, which obtained reliable results, these are either highly resource-consuming, require several sensors or need an expensive framework, making it challenging to implement this in many scenarios. Therefore, a knowledge gap exists to build a reliable, inexpensive and resource-efficient gait biometric authentication system. The paper proposes a method for using only one embedded IMU sensor with a microcontroller for tracking the motion of a subject, resource-efficient on-device elimination of the gait speed differences by proposing a homologous time approximation warping algorithm and building a resource-efficient TinyML model for reliable biometric authentication. Based on an experiment consisting of 20 human subjects with consent, the microcontroller’s on-device accuracy score for decision-making by TinyML was found to be 0.9276. The resource efficiency of the model based on memory profiling has been further discussed. Also, the prediction performance of the microcontroller with the proposed optimization was found to be only 8% slower compared to a personal computer, given that several thousands of processes run parallel on a personal computer. The work needs to be further tested for a larger sample space, and data privacy needs to be addressed.
The Internet of Medical Things (IoMT) is a subset of the Internet of Things (IoT), which consists of internet-connected medical devices, hardware, and software applications that facilitate healthcare information technology. Transformation of the healthcare sector through the adoption of IoMT devices offers significant benefits, including efficient and timely medical interventions based on real-time monitoring of patients’ vitals. Security, authentication and privacy safeguards are the key hurdles in adopting medical-grade IoMT deployment. To address these critical hurdles, a lightweight, efficient and reliable key exchange scheme, termed iSecureHealth, has been proposed. The proposed system incorporates a security control node outside the User-IoMT-Gateway paradigm to enforce end-to-end secure data transactions for a medical-grade IoMT-based patient monitoring Environment. The secure data transaction techniques and key management comprise an authentication, authorization, and access (AAA) control layer, ensuring a secure data channel between IoMT sensors and the Gateway node (GNo) paradigm. Elliptic Curve Cryptography (ECC)-based key management, using the Elliptic Curve Diffie–Hellman Key Exchange technique, provides a secure, end-to-end private health data transmission through authorized IoMT devices. We used HMACSHA256 for JWT session key generation to design a lightweight automatic authentication scheme for iSecureHealth. For mutual authentication validation, a well-known BAN-Logic is applied. We considered the widely accepted random Oracle-based Real-Or-Random (ROR) model and Dolev–Yao (DY) logic for formal and informal security analysis, respectively. A generic ESP32/ESP-32S development board connected with a multisensory (MAX30102) was used for implementation. The publisher–subscriber-based lightweight Secure Message Queuing Telemetry Transport (SMQTT) protocol demonstrates real-time streaming of sensor-acquired data over the secure transport layer. Our experiments and results show that the performance of the proposed technique is better compared to the baselines.

