"This study is an evaluation of the Archimedes spiral as a clinical technique for the diagnosis of organic brain damage . . ‥ [normal] Ss report perceiving the after-effect of both expanding and contracting spirals without a single instance of failure. Psychiatric, post-EST, and organic patients--in respective order--performed with decreasing efficiency on the same task. When the scores for the groups were adjusted for age, however, the differences between the latter three groups became statistically indistinguishable. The correlation between age and spiral score was--.39." (PsycINFO Database Record (c) 2006 APA, all rights reserved)