Proprioceptive sensation at the terminal joint of the middle finger.

Abstract

SUMMARY1. This paper extends previous work (Gandevia & McCloskey, 1976) on proprioception in the terminal joint of the middle finger. By positioning the finger in appropriate ways proprioceptive acuity at the joint can be assessed when no muscular afferents could contribute, or when afferents in the flexor but not the extensor could contribute, or when afferents from both muscles could contribute. Digital nerve block anaesthetizes joint and cutaneous receptors and so was used to study the contributions from muscle afferents in isolation.2. Displacements (100) at various angular velocities were better detected when muscle afferents from both flexor and extensor muscles could contribute. This was so whether joint and cutaneous receptors were also available, or after digital anaesthesia. Performance when only muscle afferents are available is, however, inferior to that when all sensory mechanisms are intact. It is concluded that muscle afferents contribute to kinaesthesia, and that a full complement of such receptors from agonist and antagonist muscles gives superior acuity to that achieved when only the receptors of one of the muscle groups is available.3. The angular displacements necessary for 70 % correct detection were determined at angular velocities between 0.25°and 160'/s. Proprioceptive performance was optimal with all proprioceptive mechanisms intact over the range ofangular velocities 10O-80'/s: 70 % correct detection of displacements of0-8°-1-2°occurred in this range.Performance deteriorated slightly at higher velocities of displacement. Performance was significantly poorer when only joint and cutaneous receptors could contribute (in the absence of intramuscular receptors), and when only intramuscular receptors could contribute (in the absence of joint and cutaneous receptors).4. Full proprioceptive acuity depends upon the availability of receptors in muscles and in skin and/or joints.

Differential thresholds for limb movement measured using adaptive techniques

“…The results from this experiment indicate that subjects can reliably detect an 8 % difference in the amplitude of random displacements delivered to their forearms over a stimulus range of 64: 1 and that the perceptual resolution of the forearm appears to be much greater than reported previously (Hall & McCloskey, 1983). Using quite a different experimental procedure, Durlach et al (1989) reported that the just noticeable difference in length that could be discriminated by the hand was 1 mm for reference lengths in the range of 10-20 mm.…”

“…In these studies, subjects are required to indicate when they detect a movement and its direction. This condition generally results in higher thresholds than would be obtained if subjects only indicated the presence of a movement, because this appears to be detected prior to the movement's direction (Hall & McCloskey, 1983).…”

“…Studies of absolute thresholds have demonstrated that the ability to detect movements imposed on a joint depends on the velocity of the movement and the joint being moved. As the angular velocity of a movement increases, the absolute threshold for detecting the movement decreases (Ferrell, Gandevia, & McCloskey, 1987;Gandevia, Hall, McCloskey, & Potter, 1983;Goldscheider, 1889;Kokmen, Bossemeyer, & Williams, 1977). When expressed in terms of angular rotations of the joint, these thresholds are smaller for more proximal joints, such as the shoulder and elbow, than for the more distal joints.…”

“…When expressed in terms of angular rotations of the joint, these thresholds are smaller for more proximal joints, such as the shoulder and elbow, than for the more distal joints. However, if performance is defined in terms of linear displacements of the endpoint (i.e., the fingertip for the arm), the distal joints are superior to the proximal joints (Hall & McCloskey, 1983). In these studies, subjects are required to indicate when they detect a movement and its direction.…”

“…Adaptive techniques (Levitt, 1971;Shelton, Picardi, & Green, 1982) and signal detection analyses (Green & Swets, 1989) have not been used as extensively as in other areas of perception, with some exceptions (e.g., Durlach et al, 1989;Kokmenet al, 1977;Pang, Tan, & Dur1ach, 1991;Ross & Brodie, 1987), in part because of problems associated with automating stimulus delivery and rapidly adjusting stimulus intensity. In previous studies, absolute thresholds for limb movement have been determined (Ferrell et al, 1987;Gandevia et al, 1983) and the differential threshold for limb position has been estimated (Erickson, 1974).…”