Table 1

Clinical syndromes of MND (ALS—amyotrophic lateral sclerosis) and related disorders (modified from Kato et al, 2003*, with permission)

SyndromeMain clinical featuresPrognosis
LMN, lower motor neurone; UMN, upper motor neurone.
*Kato S, Shaw P, Wood-Allum C, et al. Amyotrophic lateral sclerosis. Neurodegeneration. In: Dickson DW, ed. The molecular pathology of dementia and movement disorders. Basel: ISN Neuropath Press, 2003:350–68.
Classical (“Charcot”) MND (ALS)Usually limb (spinal) onset of weakness; bulbar involvement usual; combined UMN and LMN signs; M:F ratio 3:260–70% of all cases at presentation. Median survival 3–4 years
Progressive bulbar palsy (PBP)Onset with dysarthria followed by progressive speech and swallowing difficulties; limb involvement usually follows within months but may be delayed for several years; M:F ratio 1:1 (PBP relatively more common in older women)About 20% of all cases at presentation. Median survival 2–3 years
Progressive muscular atrophy (PMA)Almost always limb onset; >50% develop UMN signs; ,85% develop bulbar symptoms eventually; heterogeneous condition but majority are MND; M:F ratio 3–4:1About 10% of All cases at presentation. Overlap with ‘flail arm’ and ‘flail leg’ syndromes. Median survival ,5 years; more long survivors (>10 years)
“Flail arm syndrome”; “man in a barrel syndrome”; progressive amyotrophic diplegia; Bernhard-A syndrome of predominantly LMN weakness of both arms; UMN signs develop in 50–70%; often slow progression; pathology is that of MNDAbout 10% of all cases. M:F ratio 9:1; prognosis may be better than in typical ALS; ? syndrome more common in people of African and Asian origin
Vulpian syndrome
“Flail leg syndrome”; “pseudo-polyneuritic” form of MNDA syndrome of progressive leg weakness, predominantly LMN5–10% of all cases. Slow progression; must be differentiated from lumbosacral radiculopathy
Monomelic forms of MNDRare MND variant with slowly progressive focal (upper or lower limb UMN and LMN syndrome). Distinct LMN form most common in Asia (monomelic juvenile onset amyotrophy; Hirayama’s syndrome). Must be distinguished from multifocal motor neuropathyJuvenile onset form is progressive over months or several years and then stabilises; does not generalise. Pathology unknown
Primary lateral sclerosis (PLS)Clinically progressive pure upper motor neurone syndrome; after 5 years rare to convert to ALS, but may do so20 years or more
MND-dementia syndrome (MND-D)Dementia of fronto-temporal type present in ,5% of all cases of MND, but 20–40% of patients have subtle cognitive changes of “frontal” type. MND-D may present first with dementia or with MND progressing to dementia, or with a combination of both. About 50% familialUsually 2–5 years