Radial nerve palsy

[Bogey2]

Does anyone here have suggestions on how to still ride with this? (Dressage) Are there any devices that the rider could attach to the arm that would allow the use of the left rein? This is temporary but the rider is totally missing her horse!

Overview
Radial nerve dysfunction is a problem with the movement or sensation of the back of the arm (triceps), forearm, or hand.

Symptoms
Symptoms can affect the following:

Hand or forearm (“back” of the hand)
“Thumb side” (radial surface) of the dorsal hand
Fingers nearest the thumb (2nd and 3rd)
The following symptoms may occur:

Abnormal sensations
Difficulty extending the arm at the elbow
Difficulty extending the wrist
Numbness, decreased sensation, tingling, or burning sensation
Pain

[Twigster]

I had to have a radial tunnel release done on my domiant arm 10 years ago. During the rehab I learned to ride saddle-seat with just one hand with the goal of trying to ride aside (never got to though, but its still a goal!). It was a lot of fun, learning how to manage 2 and 4 reins with just one hand.

As for devices, everything that comes to mind is to aid poor grip, not painful extension of the arms. There are some tack-modification gurus on this board though, I would hunt those threads and see what the experts have to offer!