No one envies Karen Duncan her diagnosis. Motor Neuron Disease attacks the body’s nerve cells, and in Duncan’s case, it was doing so quickly. Her muscles ached and cramped; then she had to walk with a cane; then she had to motor around in a wheelchair; meanwhile, she stopped being able to trust her thoughts and emotions. Her prognosis wasn’t good either: things would get progressively worse, she would eventually be paralyzed, and then she would …