When you are not able to shift the gears with your hands to a higher or lower gear, you can order the easy shift for gears. The easy gift makes shifting to another gear easier by pushing or pulling the gear lever. You don't need to put much force to do this.
Van Raam has recently developed its own 3D print gear lever. Curious? Read all about the 3D printed shifter for Van Raam's special needs bikes in the article '3D print bike gear lever for special needs bikes Van Raam'.