MND is an extremely difficult condition to diagnose in its early stages because few cases of MND follow exactly the same pattern.
Which muscles are affected, the order in which they are affected and the way they are affected can vary so much that there are almost no rules to help predict how any one case will develop.
The first symptoms can be so subtle that it is difficult for a doctor to decide exactly what is wrong. As the area of body affected by weakness spreads it becomes easier to decide what is, and what isn’t, MND. An experienced neurologist might be reasonably sure that something is or isn’t MND but might want to see the development of more symptoms in an early or slowly developing case before being sufficiently confident that something is definitely MND.
There is currently no test for MND. Where tests are carried out, these are used to rule out other conditions.