MOTOR SYNDROMES

1. Motor Neuron Disorders (Asymmetric)

• Upper + Lower Motor Neuron Signs
• Amyotrophic Lateral Sclerosis (ALS)

• Hereditary ALS

• Sporadic motor neuron disorders with dementia
• Western Pacific ALS
• Frontal Dementia followed by motor system disease

• Lower Motor Neuron Signs only
• Distal Lower Motor Neuron (LMN) Syndrome

• Proximal Lower Motor Neuron Syndromes
• ? with IgM vs asialo-GM1
• Rare: Upper > lower limbs with anti-Hu antibodies
• Diffuse Lower Motor Neuron Syndrome without antibodies
• "Progressive Muscular Atrophy (PMA)"
• Time course similar to, or slower than, typical ALS
• Onset distal > proximal
• Progress to involve distal + proximal muscles
• Often spare bulbar musculature
• No evidence for response to treatment

• Monomelic Amyotrophy
• Onset: Young adult
• Often confined to a single arm
• Progress for 1 to 3 years, then static
• ? some patients with inelastic dura: Spinal cord compression with neck flexion¹

• Paracarcinomatous (with lymphoma)
• Weakness

• Course: Progressive then stabilizes or improves
• Associated with lymphomas
• Post-polio syndrome

2. Hereditary Spinal Muscular Atrophy (Symmetric; Proximal)

• SMN
  Chromosome 5; recessive
• Androgen Receptor (Bulbo-spinal Muscular Atrophy)
  X-linked recessive
• Hexosaminidase A (Tay-Sachs)
  Chromosome 15; recessive

3. Other SMA & motor neuron syndromes

4. Multifocal Motor Neuropathy (MMN)

5. Rapid Onset

• Acute Axonal Motor Neuropathy

• Poliomyelitis
• Porphyria
  4 types cause neurologic attacks
  All produce elevated urine d-amino-levulinic acid during attacks
• Acute intermittent
• Variegate Porphyria
• Coproporphyria
• delta-aminolevulinic acid dehydratase deficiency

6. Toxic: Lead; Dapsone; Botulism; Tick Paralysis

7. Infections

• Polio
• Creutzfeld-Jacob
• Amyotrophy
• Polyneuropathy (± Demyelinating)

8. Hand weakness

• Motor neuron disease & motor neuropathies
• Myopathies: Distal; Myotonic Dystrophy; Inclusion Body Myositis
• Myasthenia Gravis
• Peripheral nerve lesion
• Median: Recurent motor branch; Anterior interosseus
• Ulnar: Guyon canal
• Radial: Posterior interosseus
• Brachial Plexopathy

9. Painful: Diabetic amyotrophy

POST-POLIO SYNDROME

• Diagnostic Criteria: Clinical
• History of polio
• Partial or complete neurological & functional recovery
• Stable function > 15 years
• Onset of
• Fatigue
• Muscle pain
• Weakness or functional loss
• Neurological examination
• Lower motor neuron syndrome (confirmed by EMG or MRI)

• Decreased or absent tendon reflexes
• No sensory loss
• Other
• No other explanation for symptoms
• Join pain & cold intolerance may accompany the syndrome
• Laboratory features
• CK: Elevated
• Electrophysiology
• Very large motor units (up to 10 times normal)
• Some fibrillations & positive sharp waves even in stable patients
• Muscle pathology
• Near full recovery of strength & stable

• Persistent or new weakness

• New weakness & high CK

• Recommended exercise
• Mild paresis: Resistance training
• Moderate paresis: Submaximal endurance
• Severe paresis: None; Joint bracing

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1. Spine 1997;22:486-492

9/15/97