Article

The study sought to provide norms for a simple test of visual perception of
verticality (subjective visual vertical). The study was designed as a cohort
study with a balanced design. The setting was the Rehabilitation Department of a
University Hospital. Twenty-two healthy adults, of 23-58 years, 11 men (three
left handed) and 11 women (three left handed) were enrolled. A luminous bar was
displayed on a PC screen, and rotated in steps of 0.4 degrees until the
participant perceived it as vertical. A positive sign was attributed to a
clockwise rotation of the bar. The detection threshold was set at the angle
corresponding to a perceived vertical, which the participant then selected out of
three subsequent alternatives (each at +0.4 or -0.4 degrees ). The participant's
position (sitting vs. standing) and the preset angle of presentation (clockwise
vs. counterclockwise) were balanced across sex. The constant or deviation error
(dE, in degrees) and the absolute errors (aE, in degrees) were computed. An
analysis of variance model tested the dependence of dE on sex, posture, age,
handedness, and the preset angle. Both dE and aE were unrelated to sex, posture,
handedness, and the preset angle, but were dependent on age (junior, </=43 years;
senior, >43 years). The mean dE was -0.14 +/- 0.60 in the junior and 0.42 +/-
0.64 in the senior group, respectively. The minimal real difference of the dE was
0.75 and 0.25 in the junior and the senior group, respectively. The overall
median aE was 0.4 (5th-95th percentile 0-1.2) in the junior and 0.8 (0.4-1.46) in
the senior group, respectively. The whole test took no longer than 15 min in
healthy participants, and 25 min in stroke patients. The test was applied to
three subacute stroke patients with left hemiparesis, of whom two showed left
spatial hemineglect. All three patients presented with a significant clockwise
dE. This simple test appears to be valid for the routine assessment of spatial
disorders in neurological impairments.

Langue : ANGLAIS