Statistical Control Studies in Neurology

Abstract

THIS ARTICLE is the second of a series of papers dealing with the incidence of neurologic signs in "control groups." The first paper presented the results of the study on the Babinski sign.1 Further investigations have emphasized the value of such control studies from several points of view. In addition to the light thrown on the clinical value of the particular sign, these studies have revealed the frequency of abortive and subclinical forms of various diseases of the nervous system.Pronation of the outstretched hand and forearm was described by Wilson 2 as a "little sign" in acute chorea. A pronator sign was described by Str\l=u"\mpell3 in 1901 as an early sign of pyramidal-tract disease. It was studied again by Babinski 4 in 1907 and by Gierlich 5 in 1925. These three investigators pointed out that pronation of the forearm and hand at rest and when outstretched is an early sign of pyrami dal \x=req-\ tract disease. The clinical phenomenon reported in this study is apparently not related to pyramidal-tract involvement and is elicited in a different manner by quickly bringing the upper limbs in extension above the head. It is unfortunate that these two signs are known in the literature by the same name. It may be advisable to designate the sign discussed in this paper as the Wilson pronator sign. MATERIAL AND METHODIn order to determine the incidence of this sign in the general population, we examined 2,500 unselected, non-neurologic patients in a city hospital. In addition, we investigated its incidence in patients with various extrapyramidal syndromes, as listed in the accompanying table. In testing for the sign, we requested the patient to extend the upper limbs before him and then to elevate them above the head. The rapidity of the extension of the upper limb above the head was not a factor. A positive sign was one in which there was hyperpronation of the hands, on one