ALS is diagnosed in two thirds of people with MND. Early symptoms are typically painless and present as muscle weakness or stiffness and cramps in the limbs. This can cause foot drop and tripping over, a loss of dexterity, dropping things, or difficulty in raising an arm above the shoulder.^2,3,6,9

Progressive bulbar palsy (PBP) or bulbar onset MND is the initial form in a quarter of MND cases, with symptoms starting in nerves controlling muscles in the face, throat and tongue. Effects include quiet or slurred speech (dysarthria) or swallowing difficulties (dysphagia). ^2,3,9,10

Around 10% of cases start as progressive muscular atrophy (PMA) with muscle weakness and wasting in limbs, typically seen as weakness or clumsiness of the hands. There can also be muscle twitching or fasciculation.^2,9,11

Primary lateral sclerosis (PLS) is much less common with prevalence data not clear. It can take longer to diagnose, but is characterised by muscle stiffness, usually starting in the legs, and may also progress with speech difficulties.^2,9,10

Very rarely, the first symptoms of MND can be with the lungs, something which would normally occur in the later stages. Respiratory-onset signs and symptoms include breathing difficulties, shortness of breath (especially while lying flat – orthopnoea), sleeplessness, or a headache on waking due to poor oxygen/carbon dioxide exchange.

Frequent unexplained chest infection or a weak cough may also result from neuromuscular respiratory failure.^3,12