Hoover's sign – Functional leg paresis

• Hoover’s sign is a clinical sign used to differentiate between unilateral organic and functional leg weakness
• This is based on the principle of synkinetic movements

Eliciting Hoover’s sign

• Patient is asked to lie down in supine position
• The examiner keeps the palm of his hand under the heel of the patient’s normal leg
• The patient is asked to lift his ‘paretic’ leg
• Normally there is synkinetic hip extension in the normal limb and the examiner can feel the pressure on his palm
• In patients with organic paresis, there is accentuation of this response and the examiner can use the straightened normal limb as a lever to lift the whole limb and lower body
• In patients with functional paresis, there is no synkinetic hip extension and the examiner fails to appreciate any downward force
  • This occurs because the patient does not make any effort to raise the leg
• Similarly, the patient can be asked to raise the normal limb
• Patients with functional leg paresis unconsciously press down with the ‘paretic’ limb, whereas no response is obtained in those with organic paresis