Do motorcycles need handicapped plates?

Yesterday I was driving behind a motorcycle with handicapped license plates. That got me to thinking. How does one that is handicapped enough to require special plates drive a motorcycle? The bike didn’t have a sidecar, and it looked too small to really have a person riding.

The only thing I could come up with was that maybe the driver needed to walk with a cane, but if that was the case, would he have enough mobility in his legs to shift gears? It definitely couldn’t have been for vision problems, so I’m not sure. Does anyone out there know? I’m just extremely curious.