Balance cushions -- can they really help spazzy folks focus?

Lately I've got the attention span of a day-post-coked goldfish, and I get to being really wiggly in my desk chair. Notably, it's got a hard wood seat without any sort of cushion. And I can't sit in it for more than a few minutes before getting crazily distracted.

Some of my students are given inflatable rubber balance cushions or wedges by their occupational therapists, and told that these'll help induce static anatomical trunk position, limit ADHD/Sensory Integration Dysfunction symptoms, help from distracting urges to run around.

Is there any truth to this? Should I try buying one of these suckers? How about just sitting on an exercise ball? Or is this just untested hoaxy pseudo-science? I can't find any official-sounding support to these cushions (though one Texan website claims 'an 18% reduction in hyperactivity'), and I'm resentful of dropping $25.00 for a glorified balloon.