Motor Neuron Disease Motor neuron diseases (MND) describe a group of conditions where the motor nerves are damaged. Muscles connected to the damaged nerves gradually lose their strength, and this result in the muscles wasting away. [Please download the PDF file if you are unable to view the image below.] Content serves as a guide only. Seek the advice of your doctor for more details Information correct as of April 2020 Reproduced with permission from the National Neuroscience Institute (NNI)