An explicit no response instead of time-out in automated visual-field testing.

Autor: Lutz S; Department of Pathophysiology of Vision and Neuro-Ophthalmology, University Eye Clinic, Schleichstrasse 12-16, 72076 Tübingen, Germany., Dietrich TJ, Benda N, Selig B, Strasburger H, Schiefer U
Jazyk: angličtina
Zdroj: Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie [Graefes Arch Clin Exp Ophthalmol] 2001 Mar; Vol. 239 (3), pp. 173-81.
DOI: 10.1007/s004170000243
Abstrakt: Background: To evaluate the effect of response-acquisition technique on psychometric performance in visual-field testing, the conventional one-button yes/time-out method was compared with a two-button yes/no method for responding whether or not the stimulus was detected. There are a number of situations in which the single-button technique leads to ambiguous results. In this study, we thus expected the yes/no method to reduce tendencies towards habituation and automatic responding. Our hypothesis was that the two-button technique could reduce the rate of erroneous responses.
Methods: Luminance-difference sensitivity for bright stimuli (32') on a photopic background was evaluated at 26 locations within the central visual field (30 degrees) using a specially equalised video display unit and a modified 4/2-dB staircase strategy (six reversals, maximum-likelihood threshold estimation). Sixty-one ophthalmologically normal subjects (aged 20-30 years) were examined twice with each method.
Results: Mean sensitivities with the two-button yes/no method were found to be, on average, 0.13 dB above those measured with the one-button yes/time-out technique--a difference without clinical relevance. Within-subject variability did not differ between the two methods. However, the less intuitive two-button yes/no method had a slightly higher number of false responses in catch trials.
Conclusion: Compared to the conventional one-button yes/time-out method, the two-button yes/no method in normal young subjects thus showed little difference in mean sensitivities and equivalent within-subject variabilities. Concerning our initial hypothesis, the yes/no method is of somewhat higher complexity and is not able to reduce the rate of erroneous responses. The one-button yes/time-out method fared a little better in error rate. In summary, the yes/no method is an alternative and additional possibility of response acquisition in visual-field testing, which is worthy of being tested in a clinical study with elderly subjects.
Databáze: MEDLINE
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