A simple test of coordination in the fingers

IN ASSESSMENT of the fine motor activity of the upper extremity, a series of tests is commonly employed -holding the arms outstretched, touching the index finger to the nose, rapid pronation-supination of the forearm, touching the thumb to each of the fingers, rhythmic opposition of the index finger to the tip of the thuinb, patting and polishing movements of the hand, and handwriting-each examiner having his own favorite tests. These methods cannot fail to detect severe disturbances of motility, but, in the case of &or abnormalitie$, it often is not easy to decide if the imperfection is significant because either the motion of so many parts makes it difficult to judge the precision with which the maneuver is performed or the movement is so elementary that it can be carried out satisfactorily even in the presence of a certain amount of neurologic deficit. In the search for a bedside test in which the number of parts moved is restricted and in which fair accuracy and good speed can be achieved only by normal persons, the maneuver shown in the figure has been selected. It consists of tapping the tip of the flexed index finger against the thumb, opposite the distal knuckle (the interphalangeal joint), as rapidly as possible. The upward excursion of the tip of the index finger is ?4 to 21 in. Instructions are not diiescult for the patient to understand. Precision on the part of the patient must be insisted upon, and, to help in this, an ink mark is sometimes made to indicate the point to be tapped. Normal persons under the age of SO, sophisticated or not, can usually tap lightly and accurately at a rate of 3 to 5 per second, moving chiefly the index finger; the Test for finger coordination