AZUB BIKE is known for building high quality custom recumbent bikes and trikes. Among many customizations they have developed also the “push brakes” which allow disabled people to ride on trikes in case they do not have ability to operate regular brake levers.
Azub also assemble Shimano Alfine 11 with electronic shifting for easy operation and they have a couple of other options and accessories for disabled riders as well. I went to their WEBSITE and searched for what they have to offer and came up empty handed. If it is on their website I don’t know how you locate it.
A FREE GIFT awaits you!
Tadpole Rider 
I am just happy Azub has taking the opportunity to devise these implements for the impaired and disabled, as I know first hand how a debility may hinder some riders as I am in the same boat being some what debilitated myself.. So my hat comes off to the men and women of Azub for their kind efforts, in their contribution to the debilitated, and the disabled..!
Armadillozack