I'm experiencing a similar issue, but only when I ride my under seat steering delta recumbent trike. I assume it's caused by inadequate support for my elbow.

My Occupational Therapist daughter-in-law and my chiropractor son-in-law both think its a nerve issue. My son-in-law thinks he can fix it. In the meantime I'm planning to take an arm sling along with me the next time that I use that trike and, if that doesn't work, I'll jury rig an elbow rest from some kind of aero bar hardware.

Bottom line, the first thing that you try, bar ends or trekking bar, may or may not work. The bars in your picture have a little rise to them so they're probably pretty wide. A narrower straight handlebar, which will bring your hands in, might be all it takes to work better for you. You have the rest of your life to experiment until you find what works best for you. It's worth it.