Clinical syndromes of MND (ALS—amyotrophic lateral sclerosis) and related disorders (modified from Kato et al, 2003*, with permission)
| Syndrome | Main clinical features | Prognosis |
|---|---|---|
| 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 3:2 | 60–70% 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 3–4:1 | About 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 MND | About 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 MND | A syndrome of progressive leg weakness, predominantly LMN | 5–10% of all cases. Slow progression; must be differentiated from lumbosacral radiculopathy |
| Monomelic forms of MND | Rare 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 neuropathy | Juvenile 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 so | 20 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% familial | Usually 2–5 years |