Proprioception - Proprioception and Kinesthesia

Proprioception and Kinesthesia

Although the word kinesthesia is sometimes used interchangeably with proprioception, kinesthesia is the sense of body motion.

Some differentiate the kinesthetic sense from proprioception by excluding the sense of equilibrium or balance from kinesthesia. An inner ear infection, for example, might degrade the sense of balance. This would degrade the proprioceptive sense, but not the kinesthetic sense. The affected individual would be able to walk, but only by using the sense of sight to maintain balance; the person would be unable to walk with eyes closed.

Proprioception and kinesthesia are seen as interrelated and there is considerable disagreement regarding the definition of these terms. Some of this difficulty stems from Sherrington's original description of joint position sense (or the ability to determine exactly where a particular body part is in space) and kinesthesia (or the sensation that the body part has moved) under a more general heading of proprioception. Clinical aspects of proprioception are measured in tests that measure a subject's ability to detect an externally imposed passive movement, or the ability to reposition a joint to a predetermined position. Often it is assumed that the ability of one of these aspects will be related to another; however, experimental evidence suggests there is no strong relation between these two aspects. This suggests that while these components may well be related in a cognitive manner, they may in fact be physiologically separate.

Much of the foregoing work is dependent on the notion that proprioception is, in essence, a feedback mechanism; that is, the body moves (or is moved) and then the information about this is returned to the brain, whereby subsequent adjustments could be made. More recent work into the mechanism of ankle sprains suggests that the role of reflexes may be more limited due to their long latencies (even at the spinal cord level), as ankle sprain events occur in perhaps 100 ms or less. In accordance, a model has been proposed to include a 'feedforward' component of proprioception, whereby the subject will also have central information about the body's position prior to attaining it.

Kinesthesia is a key component in muscle memory and hand-eye coordination, and training can improve this sense (see blind contour drawing). The ability to swing a golf club or to catch a ball requires a finely tuned sense of the position of the joints. This sense needs to become automatic through training to enable a person to concentrate on other aspects of performance, such as maintaining motivation or seeing where other people are.