Table 1

Classical clinical features of UMN and LMN syndromes

Clinical signUMN syndromeLMN syndrome
Weakness‘Pyramidal’ distribution, that is, hip flexor and foot dorsiflexor predominantFocal or multifocal, often in peripheral nerve or root distribution
Loss of distal dexterityPresentAbsent if no sensory loss
Slowness and simplification of movementPresentAbsent
Poor balance responsesPresentAbsent
Muscular atrophySlight or absentProminent in weak muscles
Muscular toneIncreased with spasticityReduced in weak muscles
Deep tendon and superficial reflexesTendon reflexes increased or superficial reflexes diminishedTendon reflexes reduced or absent superficial reflexes normal or reduced
Babinski response (and related responses)PresentAbsent
  • Note that these traditional criteria do not include any higher-order functional tests in the case of UMN disorders, which could distinguish frontotemporal cerebral dysfunction from limited lesions in the corticospinal tracts in the brainstem or spinal cord. Internal capsular lesions frequently involve non-corticospinal descending pathways, in addition to the corticospinal pathways themselves.

  • LMN, lower motor neuron; UMN, lower motor neuron.