Sensorimotor and Sex Influence on Spatial Orientation when Sitting and Standing.

When patients experience peripheral vestibular or certain central disorders causing dizziness or vertigo, this is sometimes associated with experiencing also disrupted spatial orientation, which may be accentuated by exposure to a distorted visual environment. This study explores the impact of sensorimotor factors and sex on spatial orientation in sitting and standing positions. In the Rod-and-Frame test, the participant views a rod - with and without a surrounding tilted frame - and is assigned to align the rod vertically or horizontally. A systematic misalignment of the rod due to the tilted frame is considered a visual field dependent behavior. Our objective was to determine whether healthy young adults perform the Rod-and-Frame test equally well when sitting and standing, and to determine the test-retest reliability. Twenty-four participants, 12 males and 12 females (M age = 25.5 years, standard deviation (SD) = 2.8 years) (males M age = 26.3 SD 3.1; females M age = 24.8 SD 2.4), performed identical Rod-and-Frame tests two times - exactly one week between the tests - in a completely dark room while standing and sitting. The participants were assigned to align a luminous rod horizontally and vertically with no frame of reference; with the rod surrounded by a luminous frame tilted 20° clockwise; and 20° counterclockwise. The participants were significantly more field dependent while sitting than while standing during the clockwise frame condition. Females were significantly more field dependent than males in the sitting clockwise and counterclockwise frame conditions. The test-retest evaluation was significantly non-zero for all test conditions and most ICC values were within the "good reliability" range. Thus, during the test conditions with increased sensorimotor information, the participants were less affected by distortive visual information. Additionally, females were more affected by distortive visual information than males while sitting. The Rod-and-Frame test proved robust, providing similar results when repeated.