Clinical characteristics of classical and atypical phenotypes of ALS and other motor neuron disorders
| UMN sign | LMN sign | Asymmetry | Dementia | Endemic foci | Additional features | |
|---|---|---|---|---|---|---|
| Classical phenotypes | ||||||
| ALS | + | + | +/− | +/− | ||
| Primary lateral sclerosis | + | − | − | +/− | ||
| Progressive bulbar palsy | + | + | − | +/− | ||
| Progressive muscular atrophy | − | + | − | − | ||
| Atypical phenotypes | ||||||
| ALS-parkinsonism-dementia complex | + | + | − | + | Kii (Japan), Guam (USA), West Papua (Indonesia) | Can present as familial with different phenotypes within single pedigree |
| Madras motor neuron disease | + | + | +/− | − | Southern parts of India | Cranial nerve involvement, particularly hearing loss |
| Monomelic amyotrophy of upper limb/juvenile muscular atrophy of distal upper extremity | − | + | + | − | Japan, India | Juvenile onset, male dominance, non-progressive course |
| Monomelic amyotrophy of lower limb | − | + | + | − | India | Juvenile onset, male dominance, non-progressive course |
+, Typical characteristic; −, not a typical characteristic; +/−, may be a concurrent characteristic; ALS, amyotrophic lateral sclerosis; LMN, lower motor neuron; UMN, upper motor neuron.