Design of an exoskeleton maturing with boys with Duchenne Muscular Dystrophy

Abstract

Boys with Duchenne Muscular Dystrophy have a different life from most children. As they grow up, their muscles lose strength progressively. Around the age of 10, they lose their ability to walk, in their teens they slowly lose their arm function, in their twenties they often need respiratory support and their life expectancy is usually between 30 and 40 years old.

To support Duchenne boys’ physical functioning and contribute to their independence, a passive exoskeleton has been developed to support their arm function. The exoskeleton is designed to be physically most beneficial for boys with Duchenne between 10 and 17 years old, which is therefore defined as the target group. It is expected that, as the boys in this target group mature, both their physical and emotional needs regarding medical aids, such as exoskeletons, will change. However, the exoskeleton is not yet able to mature with the user, to accommodate for those changing needs. The design goal of this project is therefore to redesign the exoskeleton to increase its ability to mature, both physically and emotionally, with Duchenne boys from 10 to 17 years old. In order to understand the requirements needed to meet the design goal, both physical and emotional needs of Duchenne boys are researched through a literature study and user research.

Literature shows that the boys can physically benefit from the exoskeleton from the moment of wheelchair confinement (around the age of 10), but do not usually use arm supports until a much later age, or not at all, indicating a lack of perceived relevance for the target group. It also shows that there is a high variety in disease progression, so it cannot be predicted when the exoskeleton needs to be altered to fit and support the user physically.

User research shows that there are three phases of growing up with Duchenne (Naïve Playful Kid (10-12 years old), Anxious Self-Conscious Teen (12-15 years old) and Constrained Reluctant Adolescent (15-17 years old)), who differ on topics such as confidence level, attitude towards their disease, responsibility, social life, relation with their parents, and relation towards healthcare products. Products can have a positive influence on emotional development if they can improve independence and individual functioning. Products can have a negative influence if they feel like an imposition, if the user has no control or choice over them, and if the introduction or alteration of the products confirm further muscle decline.

For the exoskeleton to fit with the physical and emotional maturing process, it should therefore achieve the following design goals. The use of the exoskeleton should be made more relevant for each of the three emotional phases of growing up; the user should be able to focus on positive progress and anticipate on negative decline; the exoskeleton should accommodate for an increasing responsibility and independency of the user; and the user should feel like he has a sufficient amount of control and choice over the exoskeleton.

For the exoskeleton to achieve these goals, a new concept is proposed, which consists of three components. Firstly, the exoskeleton is given an added functionality of controlling devices in the user’s house, by making movements. Secondly, an interface containing a coding platform enables the user to decide which devices are controlled with which movements, and through a communication platform he can ask questions and share experience. Thirdly, a service in which an expert regularly checks the exoskeleton’s hardware (physical fit and support) and software (controlling functionality).

The concept increases the ability of the exoskeleton to mature with its user, because it ensures the exoskeleton fits well with the needs of all different ages in the target group and because the target group expects the concept to remain interesting for a longer period of time. They expect this because of the amount of possibilities and adaptabilities the interface provides, but also because of the combination of fun and extra independence the extra controlling function provides directly when using the concept. Furthermore, the expert service ensures the physical fit and support of the exoskeleton is regularly checked and updated, without confronting the target group negatively regarding their physical decline. By implementing the concept, the exoskeleton is expected to continue to be relevant for boys with Duchenne and give them a more positive experience as they mature from children to adults.