[Value or lack of value of the Landwehr so-called balance scale]

A screening investigation was carried out at our department to study the equilibrium balance according to Landwehr, which is used for X-ray photographs as well as for Moiré or grid photometric analyses of the spine while standing in the upright position. If has been demonstrated that the balance could be "deceived" without difficulty by persons who are aware of its mechanism of action and who intend to do so, which means that its application does not necessarily yield "faultless reproducible radiographs", as Bernau has insisted. If the experiment is carried out with persons standing on the balance without prejudice, there is a high probability of better reproduction of the posture than without using the balance, though particular cases may assume an unnatural posture. A screening investigation using the equilibrium balance with 3000 pupils yielded 12% less false positive results. As a consequence of this investigation, we believe that after weighing the advantages and disadvantages, we can recommend the balance for both X-ray photographs and Moiré as well as grid analyses of the dorsum. In addition, appropriate use of the equilibrium balance provides better comparison of different results of treatment.