The application of a use case/task based approach in the development of software for a portable neuromuscular stimulator device

This paper describes the use of a use case/task based method in the development of a portable neuromuscular stimulator device. The developed unit allows a variety of stimulus delivery algorithms to be incorporated dependent on the patient's requirements. The developed system consists of a stimulator unit, stimulator firmware, external sensors, a programmer unit, two stimulation channels and electrodes. A clinician specifies a suitable algorithm for a particular patient and then selects the relevant stimulus parameters for that algorithm using the programmer unit. The stimulator unit's architecture supports the addition of future algorithms. The device was developed in accordance with the European Medical Devices Directive 93/42/EEC resulting in the need for a well-defined development lifecycle during the design and development of the neuromuscular stimulator. This development lifecycle must place emphasis on the need to identify potential hazards. Therefore, the adoption of a use case/task driven approach as one of the strategies in eliciting the requirements, both functional and non-functional and specification stages of the development lifecycle resulted in a more rigid hazard/risk analysis leading ultimately to a more robust final system. A comprehensive review of the literature has revealed that use cases have been in use in other contexts but not so in a biomedical context. Therefore, this is a novel strategy to the development of a device in this field. A brief background on the historical development of drop foot stimulators shall be presented thereby displaying the benefits of the programmability feature of our stimulator.