Most people with motor-neurone disease (MND) do not experience loss of mental ability. However, a small percentage (around 10%, but possibly as many as half) may gradually develop difficulties with planning, language, memory, judgement and the regulation of behaviour and emotion.
Personality may change – becoming more impulsive, outgoing, inappropriate or apathetic. Another common symptom is emotional lability: uncontrollable crying or laughter. These changes may become severe enough to be termed dementia.
MND usually has a short course before death: the average life expectancy is three to five years from diagnosis, although 10% of people with MND live 10 years or longer. As the disease progresses, you may experience decreasing mobility and ease of breathing.
Ultimately, death is often due to respiratory failure or aspiration pneumonia. It is generally not violent or painful: many people with MND simply fall into a deep sleep and do not wake, often in their own home.