Amyotrophic lateral sclerosis (ALS) is the most common type of MND, causing mixed upper and lower motor neurone disease.

Primary lateral sclerosis is rare and characterised by an ascending spastic tetraparesis. Progressive bulbar palsy more often affects women and typically progresses to anarthria in 6–12 months with normal limb strength. Progressive muscular atrophy is the least well-defined subtype of MND, and presents with asymmetrical weakness and wasting, often in the legs.

MND may first present with cognitive decline - up to 15% of people with MND can develop severe frontotemporal dementia.

Features of bulbar palsy (dysarthria, dysphagia and tongue fasciculation) indicate a poor prognosis. Weight loss and older age at onset associated with shorter survival times.

Motor Neurone Disease: assessment and management (NICE, 2016), Motor neurone disease (NHS Choices), MND association (mndassociation.org), Amyotropic Lateral Sclerosis (Mayo clinic), AboutBFS (About Benign Fasciculation Syndrome), ​Neurosymptoms.org