Elbow Matching Accuracy in Young and Elderly Humans under Unusual Mechanical Constraints.

Experiment was carried out to study the proprioception accuracy of elderly (61-83 years old) and young (22-36 years old) subjects during contralateral elbow matching in sagittal plane. The subjects performed the task under ordinary condition and under experimental condition (matching forearm attached to the rocking cylindrical platform of low (LS), or high (HS) height, so that the elbow flexion was associated with tilting movement of the support and with backward movement of the upper arm). Control matching of young and elderly subjects does not differ significantly in terms of constant and absolute error.

[Spectral Analysis of Sway of Human Body When Standing on Firm and Compliant Surfaces under Different Visual Conditions.].

The influence of different visual conditions on maintenance of vertical posture when standing on a firm and a compliant surface were compared. Motionless visual environment (MVE), closed eyes (CE) and virtual visual environment (VVE) were used as visual conditions. Displayed VVE included foreground and background.

[The Influence of Light Tactile Contact on the Maintenance of Vertical Posture under the Conditions of Destabilization of the Visual Environment].

We studied the influence of a light contact of the index finger with a stationary surface of external environment on the maintenance of upright posture in healthy subjects "immersed" in unstable virtual visual environment. Under these conditions, the subjects saw the screen with a visual scene consisting of foreground and background. The foreground represented a window of a room with adjoining walls; and the background plan--an aqueduct with the adjacent terrain.

Does the stability of elbow support influence the elbow joint matching accuracy?

The aim of the present work was to determine if the elbow joint instability and translatory movements during elbow flexion lead to significant errors in elbow angle perception. The matching elbow was fixed on a rocking platform of two different heights so that the elbow flexion was associated with tilting movement of the support and the angle/torque relationship changed depending on the height of the platform. The matching on any of the rocking supports did not cause an over-flexion constant error but it did increase the error variance, especially in the high rocking support condition.

The effects of moving sound images on postural responses and the head rotation illusion in humans.

The results of pilot studies on the effects of sound images moving in the horizontal plane on poststimulus responses and the head rotation illusion are presented. These phenomena are demonstrated to occur.