They survive without water by entering a special mode, otherwise called as shriveling. They can lose even 95% of water in their body and still live, even though they would look like dead plants, they would actually be alive. In the absence of water, tardigrades use a sugar called trehalose, which becomes their source of life until they find some water.
Motor neuron disease includes loss of motor neurons in the anterior horns of the spinal cord and motor nuclei of the lower brain stem.