Hoover's sign: Clinical relevance in Neurology.

Hoover's sign was described by Dr. Charles Franklin Hoover more than 100 years back to differentiate between the organic and functional weakness of pyramidal origin. This test is usually performed in the lower limbs and is valuable when on bedside one is not sure about the nature of hemiparesis. A subject with hemiparesis of organic cause while asked to flex the hip of normal leg against resistance will not exert pressure on the hand of examiner placed under the heel on the affected side while in hysterical weakness heightened pressure will be felt on the examiner's hand. The presumed genesis of this sign could be the crossed extensor reflex or the principle of synergistic contraction. It is a useful clinical test in differentiating functional and organic paresis with moderate sensitivity (63%) and high specificity (100%), but there are some limitations which should be kept in mind while evaluating a patient.