Friday, 4 May 2012

Clinical skills: Hoffman's reflex

Level 1
The test involves tapping the nail or flicking the terminal phalanx of the middle or ring finger. A positive response is seen when terminal phalanx of the thumb flexes. A positive Hoffman's reflex indicates an upper motor neuron lesion or a pyramidal sign. 

In my experience Hoffmann's reflex are often symmetrically positive in normal people, particularly in subjects with brisk reflexes, which is why I seldom use this test myself. An asymmetrically positive Hoffmann's sign is more worrying and is likely to be pathological.

Hoffman's reflex is similar to a deep tendon reflex and is mediated by spindle fibres and is therefore a monosynaptic reflex pathway. In other words it should be interpreted as you do tendon reflexes. In comparison, the plantar or Babinski's reflex is not a deep tendon reflex and hence is always considered pathological in adults.

Other relevant posts of interest: Babinski's sign, tendon reflexes

History of neurology: Johann Hoffmann (March 28, 1857 – November 1, 1919, Heidelberg) was a German neurologist remembered for describing the reflex above and Werdnig-Hoffmann disease (infantile spinal muscular atrophy or SMA).

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