Scoring of a ´Steadiness' Test.

Journal/Book: Reprinted from Nature Vol. 185 No. 4709 pp. 337-338 January 30 1960. 1960;

Abstract: Department of Pharmacology and Therapeutics The University Sheffield 10. Nov. 17. A TEST of ´steadiness' has been used in this Department as a class experiment in order to illustrate the importance of the ´double blind' principle in the design of controlled clinical trials. The apparatus of Seashore and Adams1 was chosen. Steadiness is measured as the ability to hold a metal stylus in position for a fixed period within holes of graduated diameters drilled in a metal plate without allowing the stylus to come into contact with the sides of the hole. An index of steadiness is obtained by multiplying the contact times for each hole by arbitrary factors related to the hole diameters and summing the result. The timer used in this experiment was constructed from ´Add-on' dekatron units (Ericsson Telephones Ltd. Beeston Nottingham). A time signal (100 p.p.s.) is fad into the counting device through the Input selector. With the ´count' key fixed in the reset position the counter is set up for automatic starting and resetting through the socket of the terminal dekatron unit the connexions being made by means of a 12-pin miniature Jones plug. The Counter starts operating when the terminal PLA9 is earthed and is reset by removing the earthing temporarily from PLA10. In the ´start' circuit there is a Post Office ´Uniselector' driven by 40 V. d.c. Pulses from a time clock. The contacts in the ´Uniselector' are connected in such a way that after a 2 · 5-sec. interval the ´start' circuit is completed for a period of' 10 sec. The ´Start' circuit also contains a high-speed relay which is actuated by a 40-V. d.c. current ´made' when the stylus touches the sides of the hole. The relay closes the ´start' circuit and the counter operates. When the stylus is not touching the edge of the hole the relay contacts are open and the counter stops. Readings are thus obtained directly (in units of 0 · 01 sec.) of the time in a 10-sec. test period during which the stylus is in contact with the hole. ... ___MH

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