Some people have need of single hand controls and/or single foot propulsion on a tadpole trike. These are available and equipped with them cyclists can ride, get exercise and enjoy the experience. Here is a video showing one such person …
There are dealers who offer specialized components and outfitting of trikes for customers who need such. HERE is one of them. Adaptive controls can be ordered thru and fitted by ICE trikes. And I am sure that the infamous Utah Trikes would gladly outfit a trike for anyone needing special controls and components.