The cramp/spasm you describe can be an MS thing, i think they refer to this type of spasm as clonus (not sure about that though). I get this type of intermittent spasm in my hand, any kind of activity that require a thumb and index finger type of grip ( like holding a pen or pencil) for more than a couple of minutes, will cause my hand to lock up completely. The spasm is so intense that it hurts like H*** and i just have to stop trying to use my hand so that it eventually eases off- the trouble is that for some time afterwards any attempt to use my hand at all will just instantly bing on the spasm again. I tried baclofen but it did not really help, i was told if were in different muscle groups it may be possible to have a botox shot but it would mean i lost too much dexterity if they used it for my hand. Eventually my GP suggested that i try a magnesium supplement and that has actually reduced the frequency of the spasms. My PCP did also give me some diazepam in for times when i still have severe spasms