Table 1 Frequencies and percentages of subjects in diagnostic groups of motor neuron disease

DiagnosisFrequencies (% of all subjects)
* Diagnoses among 152 controls: peripheral neuropathies (16.1%); MG (10.3%); benign fasciculation (7%); muscular dystrophies (7%); inflammatory myopathies (6.5%); other myopathies (5.8%); movement disorders (4.5%); mitochondrial disorders (3.2%); cervical or lumbar spondylosis (3.2%); benign cramp syndromes (2.6%); MS (1.9%); and other conditions (13%, each less than 2%).
ALS with upper and lower motor neuron signs (ALS)172 (40)
ALS with lower motor neuron signs and probable upper motor neuron signs (active tendon reflexes in limbs with lower motor neuron signs but no clonus, Hoffmann signs, or Babinski signs) (ALS-PUMNS)58 (14)
Progressive spinal muscular atrophy (lower motor neuron signs only) (PSMA)30 (7)
Primary lateral sclerosis without lower motor neuron involvement (clinically or on electromyography) (PLS)19 (4)
Controls* (other neurologic diseases)152 (35)