Observations of movement are best achieved in conscious patients, either by watching as patients attempt movement or by requesting patients to undergo specific movements for the purpose of observation. A total loss of the ability to move is paralysis, a major neurological deficit that may be local (e.g. in one limb) or involve wider aspects of the nervous system. Movement problems could be classified into losses and excesses. Losses include a reduced level of movement, called hypokinesia, the inability to initiate a movement, called akinesia, and a total loss of movement, referred to as a paralysis. Motor neuron disease is a progressive degeneration of motor neurons, this time the pyramidal (corticospinal) tract fibres, some cranial nerve nuclei and some lower motor neurones within the cord. It causes severe movement losses involving motor control of the swallow reflex, and death occurs within a few years.