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Motor and Sensory Syndromes

Last Updated: September 27, 2018


Table 1: Upper Versus Lower Motor Neuron Weakness
Key signs to differentiate a lower versus upper motor neuron etiology for weakness
Deep Tendon Reflexes
  • UMN – Increased (decreased acutely or with cerebellar signs)
  • LMN – Decreased
Distribution of Weakness
  • UMN – more prominent in UE extensors and LE flexors, unilateral, rarely isolated to a particular muscle group (can be paraparetic / quadriparetic), rarely bilateral CN
  • LMN – Isolated weakness to a particular muscle group (can be paraparetic, quadriparetic, bilateral CN) 
Resistance to Passive Motion
  • UMN – Increased (decreased with cerebellar lesions)
  • LMN – Decreased
Pathologic Reflexes
  • UMN – Observed
  • LMN – Not observed
Additional Symptoms
  • UMN – Sensory anomalies, primit...