Proprioception Loss: Blinding the Mind From the Body

by Emily Douglass

Stephen F. Austin State University, Spring 2000

Proprioception can be described as the mind's awareness of the body. Proprioception provides the central nervous system unconscious information about the body (Bluestone, 1992). The "awareness" of our body may be difficult to understand until we have lost our proprioceptive sense. Researchers concerned with proprioception have usually directed their studies toward identifying in what processes proprioception plays a major role, and what processes may be hindered if proprioception loss is severe. Unfortunately, not much is known about proprioception, or how much proprioception contributes to functional accuracy (Gordon, Ghilhardi, & Ghez, 1995).

Sherrington (1961) declares that the proprioceptive receptors, the nerves associated with proprioception, are effective at determining changes inside the organism; which is where the term "proprioception" originates. He explains that proprioceptive receptors are used especially in muscles and their accessory organs. Proprioceptive receptors and some receptors in the labyrinth (equilibrium detector located in the inner ear) work together to form our receptive systems. Finally, Sherrington shares that proprioception is responsible for continuous reflexes in skeletal muscles. In other words, proprioceptive receptors are responsible for detecting when an area of the body is out of its natural state and prompts the muscles to return the area to a resting state. Proprioception may be best understood by looking at cases of proprioceptive loss.

To illustrate the profound effects of proprioceptive loss, Oliver Sacks documented a clinical case of a woman who lost all proprioception (1985). Sacks declared that the sense of our bodies relies on three things: vision, the vestibular stystem, and proprioception. His client lost all proprioception and could not walk without watching her own legs, or talk without listening to her own voice. She could not truly determine if she had a body. The patient could not perform any motor movements most people would deem natural without relying on environmental feedback to achieve the simplest maneuver. Oliver Sacks' clinical story reflects how much the mind depends on proprioception for even the most rudimentary actions not thought consciously considered. The following research demonstrates the importance of proprioception.

A group of researchers conducted a study to determine the deficits caused by the lack of neck and body proprioception (Blouin et. al., 1995). Their experiment consisted of normal individuals as well as a patient who had permanent and selective loss of neck and whole body proprioception. They determined through clinical tests that the patient could not "maintain upright posture without losing balance [or] perceive passive body rotations with the head stationary" (p. 2216). They required the subjects to determine the amount of passive body rotation (they were rotated by someone else, while sitting in a chair). When the lights were illuminated, the patient without proprioception could determine how much her body had rotated. However, when the lights were not turned on and she had no visual cues, her perception of body rotation was disrupted. The other participants were much more accurate at determining the amount of passive body rotation with and without visual cues than the woman with proprioceptive loss. Like Oliver Sacks' patient, she needed visual feedback to determine the position and movement of her body.

Sainburg, Ghilardi, Poizner, and Ghez's (1995) study elaborates on the idea that joint proprioception plays a crucial role in the knowledge of moving limbs. To assess the role of proprioception and limb movement, the authors had subjects pretend as if they were cutting bread. The action of cutting bread requires a forward motion followed by a reverse motion. The subjects with normal proprioception made the motions in the normal fashion. However, the subjects who had proprioceptive loss made circular patterns with their arms instead of back-and-forth motions. The authors determined that proprioception plays a very critical role in the control of joints and motion. The patients who had proprioceptive loss were able to correct the circular motions if they were allowed to look and program their motions before they began the cutting demonstration. The authors' research demonstrates the ease of movements that accurate proprioception allows. The role of proprioception in accurate movements has been studied extensively.

Gordon et. al. (1995) conducted two sequential studies probing the relationship between reaching movements and proprioception. Their first study focused on spatial errors. They found that subjects who had proprioceptive loss had trouble with slow motion movements. The participants were instructed to point to a visual target presented on a computer screen. They discovered that subjects without proprioception had difficulty touching the target if they were instructed to touch the target slowly. The authors also found that the participants with proprioceptive loss had extensive directional errors in comparison to subjects with normal proprioception.

The second phase of the authors' study focused on the construct of visual information and accuracy. The experimenters instructed subjects to use cursors to click on a target presented on a computer screen. A signaling tone sounded, and the subjects were to make one, swift motion to touch the target without permission to readjust their aim. The researchers discovered that subjects with proprioception loss could not detect their own accuracy errors when the lights were turned off. The researchers deduced that seeing the limb was needed for the subjects with proprioception difficulties to use the appropriate muscles to perform the tasks (Ghez, Gordon, & Ghilard, 1995). Their combined research clearly presents how important visual knowledge of body positions and actions are for people who have lost their proprioceptive awareness of their body. The roles of proprioception and vision are demonstrated by the following research.

Rossetti, Desmurget, and Prablanc (1995) conducted research to test if vision or proprioception play a bigger role in the knowledge of body positions. They tested three constructs of coding information. The three constructs were vision-to-vision, proprioception-to-vision, and vision-proprioception-to-vision. Vision-to-vision is based on the idea that vision, and vision solely assists subjects to accurately pinpoint a target in a visual display. Proprioception-to-vision suggests that proprioception alone is responsible for accurate target location. Finally, vision-proprioception-to-vision insinuates the need for the interaction of vision and proprioception to accurately locate a visual target. Their method included subjects with normal proprioception and those without proprioceptive sense. They concluded that the combination of visual and proprioceptive information assist the subjects in accurately locating the target. Based on their findings, the authors declare that proprioceptive information may weigh more in the localization process than only visual information.

Guedon, Gauthier, Cole, Vercher, and Blouin (1998) conducted research to further examine the role of proprioception and limb movement. They designed their experiment to include a more dynamic motion of the arms that would be seen in real-life circumstances. The subjects were instructed to track a trajectory presented to them on a computer screen placed one meter away from their seats. The authors recorded the subjects' ability to accurately follow the trajectory of a circular moving target with their arm of choice. The researchers designed the apparatus to alternate the ratio of arm movement to relative tracking movement to emphasize tracking motions one might experience in daily life. The experimenters compared the results of seven control subjects to one subject with proprioception loss. The results showed that subjects use proprioception to adjust their tracking when the visual cue of their tracking changed on the screen. The subjects would look at their arm and adjust their tracking movements to correlate with what they saw on the screen.

Much of the research on proprioception has been dedicated to finding out what actions proprioception hinders or helps. There have not been many research designs constructed to discover how to help those with proprioceptive loss. Oliver Sacks (1995) describes the rehabilitation of his patient as teaching her how to use visual and auditory feedback to control the body as proprioception used to do. Rossetti et. al. (1995) claim that in patients deprived of proprioception use vision to help with proprioceptive functions. However, what should happen to a patient with proprioceptive problems if he or she should go blind? Since most of the research cited above discusses the use of visual aids in controlling body movements, sensing body motion, and accurately reaching for visual targets, one could only imagine the effects of blindness on a person who has lost proprioception.

Oliver Sacks (1985) also expressed how his patient used auditory feedback to command her speech. He explains how his patient was mute until she taught herself to speak again using the sound of her voice to communicate properly. What would happen if someone using the sound of his or her own voice to modulate speech became deaf? Proprioception research should not just be dedicated to what proprioception is responsible for, but how to help those who have proprioceptive loss. According to Paul Haber (1986) over 80 percent of people over the age of 70 have some proprioceptive loss. As our population of elderly grows, problems with proprioception will become more prominent. The need for more research in rehabilitative measures for people suffering from poor vision and hearing should be very apparent.

The current research on proprioception provides a background of information pertaining to what proprioception is responsible for, assists with, and accompanies. People with proprioception loss may learn new ways to adapt to their lost senses. New methods of rehabilitation could prove fruitful. However, with advanced technology, the possibility of regenerating damaged sensory nerves should be closer now than ever. Hopefully more research will be conducted in fixing proprioception loss. Since the majority of people alive today may one day reach the age of 70, researching ways to eliminate the effects of proprioception loss should be initiated.

References

Blouin, J. , Vercher, L. J. , Gauthier, G. M. , Paillard, J. , Bard, C. , Lamame, Y. (1995). Perception of passive whole body rotations in the absence of neck and body proprioception. Journal of Neurophysiology, 74, (5) , 2216-2219.

Bluestone, J. (1992). HANDLE. [On-line] . Available: http://www.handle.org/miscinfo/glossary.html

Ghez, C. , Gordon, J. , Ghilhardi, M. F. (1995). Impairments of reaching movements in patients without proprioception. II. Effects of visual information on accuracy. Journal of Neurophysicology, 73, (1) , 361-372.

Gordon, J. , Ghilhardi, M. F. , Ghez, C. (1995). Impairments of reaching movements in patients without proprioception. I. Spatial errors. Journal of Neurophysicology, 73, (1) , 347-360.

Guedon, O. , Gauthier, G. , Cole, J. , Vercher, J. L. , Blouin, J. (1998). Adaptation in visuomanual tracking depends on intact proprioception. Journal of Motor Behavior, 30, (3) , 234-248.

Haber, P. A. L. (1986). Technology and aging. The Gerontologist, 26, (4) , 350-357.

Rossetti, Y., Desmurget, M. , Prablanc, C. (1995). Vectorial coding of movement: vision, proprioception, or both? Journal of Neurophysiology, 74 (1) , 457-463.

Sacks, O. (1986). The man who mistook his wife for a hat: And other clinical tales. New York, NY: Summit Books.

Sainburb, R. L. , Ghilhardi, M. F. , Poizner, H. , Ghez, C. (1995). Control of limb dynamics in normal subjects and patients without proprioception. Journal of Neurophysiology, 73, (2) , 820-835.

Sherrington, C. S. (1961). The integrative action of the nervous system. New Haven, CT: Yale University Press.

Links

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