I would recommend having your calcium, potassium and magnesium levels checked, in particular the potassium level because some diuretics are notorious for depleting potassium levels which is probably why you were told to eat the bananas; foods high in potassium.
Generally this is due to a calcium deficiency. The first treatment of choice is two glasses of milk a day or a calcium supplement.
Ocasionally it is due to a magnesium or potasium abnormality.
Bannanas contain potasium and you might try eliminating them.
It is probably not a neurological disorder.