[Age-dependent changes in the square drawing test].

The square drawing test (SDT) is vertical writing test, conducted to evaluate equilibrium, done with the subject blindfolded. We investigated the development of equilibrium and presbyastasis by using SDT. Fifty three children underwent SDT every year for nine years (5-14 years old). Sixty six healthy elderly subjects (65-88 years old) were also examined. Control results were obtained from 117 young adults (22-33 years old). Four parameters of SDT (the total of each length, the whole length, the deviation angle and the start-end distance) were calculated with an SDT-computer and subjected to statistical analysis. Through the seventh grade, at least one of the parameters of SDT was statistically different from that in young adults. These differences were not observed in eighth grade children. Most parameters of SDT in elderly subjects were statistically different from those of control subjects. These results suggest that the equilibrium function matures at approximately 14 years of age and is commonly impaired after 65 years of age.