Value of Ankle-jerk Timing in the Assessment of Thyroid Function

The delayed relaxation of the tendon-jerk in myxoedema was first described by Ord (1884), and in 1924 Chaney, using a pneumatic recording system, measured the tendon-reflex time in myxoedema and showed that it returned to normal with treatment.In 1929 Mussio Fournier demonstrated rapid tendon reflexes in thyrotoxicosis.Various techniques have since been devised for timing the ankle-jerk.The movement of the foot has been transmitted to a pedal recording electronically (Lambert et al., 1951; Smart and Robson, 1963; Miles and Surveyor, 1965), or to a wire moving through an electrolyte solution which completes an electrical circuit (Mioulopoulos et al., 1964).The photoelectric method (Photomotograph) of Gilson (1959), depending upon interruption by the foot of a beam of light activating a photo- electric cell, has been used by Fogel et al. (1962), Avera and Overholt (1962), Sherman et al., (1963), and Simpson et al. (1963).The electromagnetic system (Kinemometer) of Lawson (1958), in which movement of a magnet attached to the foot induces a current in an adjacent coil, was used by de Gennes and Deschamps (1961), Mann (1963), and Nuttall and Doe (1964).This apparatus commended itself to us because of its simplicity and convenience, and has been employed in this present study.It is now generally established that the tendon reflexes are shortened in the majority of thyrotoxic patients and prolonged on 22