The kinesthetic senses

This paper came to my attention yesterday: The kinesthetic senses by Uwe Proske and Simon Gandevia, in Australia. By some refreshing turn of events, it is open access. It provides an historical backdrop to nearly everything we as physical therapists are about. We are all about restoring this function, kinesthesia, to people in whom it would seem to have gone missing. We always have been. Without good kinesthesia, motor control goes offline. When motor control goes off line, so does maximal function.

The paper begins with a brief intro to kinesthesia. It states at the outset that muscle and skin receptors account for most of the receptor input that helps the brain make motor choices. It specifically states,

"Peripheral receptors which contribute to kinaesthesia are muscle spindles and skin stretch receptors. Joint receptors do not appear to play a major role at most joints."

Wow. Right there, we can see a huge erosion under the sea shore of one of the defining organizational principles of orthopaedic manual therapy, which is that getting to and wiggling or popping the right joint in the right way will jumpstart a better motor output. Orthopaedic manaual therapy (and chiro) have used this idea to build themselves and have perpetuated it for decades, for a century. It's just not valid. It was a false hypothesis, and finally research has begun to trickle out that suggests this is the case.

After a brief description of the contribution of muscle spindle receptors to the kinesthetic senses, Proske and Gandevia begin to discuss receptors found in skin:

"Concerning the possible contribution to kinaesthesia from other receptor types, the summary view is that while a good case has been made for some cutaneous receptors, the evidence is less convincing for joint receptors. The cutaneous receptor most likely to subserve a kinaesthetic role is the skin stretch receptor, the slowly adapting Type II receptor served by Ruffini endings (Chambers et al. 1972; Edin, 1992). For kinaesthesia at the forearm, stretch of skin over the elbow during elbow flexion can provide information about both position and movement. Movement illusions generated by stretch of skin of the hand and over more proximal joints, when combined with muscle vibration were greater than when either stimulus was applied on its own (Collins et al. 2005). The authors made the point that this was not just a matter of skin input facilitating the muscle input and that cutaneous input generated by skin stretch contributed to kinaesthesia in its own right. More recent observations have shown that skin input can also have an occluding action. Signals from local, rapidly adapting receptors evoked by low-amplitude, high frequency vibration can impede movement detection (Weerakkody et al. 2007).(....)
While joint receptors were first thought to be all-important in kinaesthesia, the present-day view is that their contribution at most joints is likely to be minor. Typically they respond to joint movement, but often with response peaks at both limits of the range of joint motion (Burgess & Clark, 1969). They are now thought of as limit detectors. However, there are examples in the literature of responses across the full range of joint movement (Burke et al. 1988) and here joint receptors may play a role under circumstances in which input from muscle and skin is not available (Ferrell et al. 1987). "

My bolds.

This paper is an important one for manual therapists who seek to understand how it is that "light" manual techniques seem to do as well to help patients' brains connect up in terms of improved, observable motor output, as heavy joint-based, manipulative or mobilizing ones.

Proske, U., & Gandevia, S. (2009). The kinaesthetic senses The Journal of Physiology, 587 (17), 4139-4146 DOI: 10.1113/jphysiol.2009.175372

Engineers are interested in skin

For years I've been talking and promoting skin stretch as a not just a good avenue for kinesthetically influencing another human nervous system, but as probably one of the best ways:

1. the easiest, because skin is already out there, the first thing one "touches", and is already set up neurologically, connecting that person's brain with/for contact with environment

2. most practical, because it is the most highly innervated and therefore sensitive, and doesn't require much physical strength or special leverage from a practitioner

3. strongest neurologically, in terms of response elicited for effort made, and results gained for time spent.

It's the easiest way to stimulate physiologic nonconscious movement for the person's own brain to then harness into pain relief of ordinary uncomplicated mechanical pain or stiffness. I've worked this way for a couple decades now. (Elsewhere I've referred to this as "dermoneuromodulation", and to dermoneuromodulation as a major feature of "human primate social grooming.")

Earlier today I found a paper by some mechanical engineering students at Stanford who seem awfully interested in skin stretch. I think they are investigating haptic capacity - maybe they want to build better robots which can carry tea in expensive china without either
a) spilling tea, or;
b) dropping and breaking the china.

It's by Bark et al., and called Comparison of Skin Stretch and Vibrotactile Stimulation for Feedback of Proprioceptive Information; it can be found online (here's an html version I found).

I very much admire the way in which engineers simply read, absorb, accept things that are obvious at face value, and move on to develop cool applications based on research. My profession is so determined to seem scientific on the one hand, yet is so mired in "traditional" ways of applying manual therapy that it won't let go of visualizing everything backwards, from the joints out. See the attached Shaffer paper. (At least it does actually mention cutaneous receptors as maybe being somewhat important for balance and equilibrium...)

But generally, trying to get my own profession interested in the sensitivity and handling of skin is very difficult. It would rather contemplate bones, joints, muscles, and in general, innervation of mesoderm, rather than realize that the brain of a patient is always going to register skin contact first, at multiple levels which will react accordingly.

The Bark paper is loaded with excellent references to do with skin stretch and how it might apply to haptic possibilities for mechanical devices. See at bottom.


Additional Reading:

Shaffer SW, Harrison AL; Aging of the Somatosensory System: A Translational Perspective. (15-page pdf) Physical Therapy Vol 87 No 2 Feb 2007
.

From the Bark paper:
[1] K. Bark.Preliminary results from skin stretch perception tests,http://bdml.stanford.edu/twiki/bin/v...ontesting,2007.

[2] K. Bark, J. Savall, and R. Holop. Measuring skin stretch strain, http://bdml.stanford.edu/twiki/bin/v...roperties,2007.

[3] J. Biggs and M. Srinivasan. Tangential versus normal displacements of skin: Relative effectiveness for producing tactile sensations. In 10th International Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, pages 121–128. IEEE ComputerSociety, 2002.

[4] D. Caldwell, N. Tsagarakis, and C. Giesler. An integrated tactile/shear feedback array for stimulation of finger mechanoreceptor. International Conference on Robotics and Automation, pages 287–292, 1999.

[5] D. F. Collins, K. M. Refshauge, G. Todd, and S. C. Gandevia. Cutaneous receptors contribute to kinesthesia at the index finger, elbow,and knee. Journal of Neurophysiology, 94:1699–1706, May 2005.

[6] B. Edin and N. Johansson. Skin strain patterns provide kinaestheticinformation to the human central nervous system. Journal of Physiology, (487):243–251, 1995.

[7] B. B. Edin. Cutaneous afferents provide information about knee joint movements in humans. The Journal of Physiology, (531.1):289–297,2001.

[8] B. B. Edin. Quantitative analyses of dynamic strain sensitivity in human skin mechanoreceptors. Journal of Neurophysiology, 92:3233–3243, 2004.

[9] F. Freybergery, M. Kuschel, B. Farber, M. Buss, and R. Klatzky. Tilt perception by constant tactile and constant proprioceptive feedback through a human system interface. In Second Joint EuroHaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, March 2007.

[10] M. Fritschi. Design of a tactile shear force prototype display. Inhttp://www.touch-hapsys.org, page Work package 6, 2003.

[11] E. Gardner and J. Martin. Coding of Sensory Information, chapter 21,pages 411–429. Principles of Neural Science. McGraw-Hill, fourth edition, 2000.

[12] E. Gardner, J. Martin, and T. Jessell. The Bodily Senses, chapter 22,pages 431–450. Principles Of Neural Science. McGraw Hill, fourth edition, 2000.

[13] G. D. Garson. Univariate glm,anova,and ancova”from statnotes:Topics in multivariable analysis. In http://www2.chass.ncsu.edu/garson/pa...htm,volume2007, page 1, 2007.

[14] G. M. Goodwin, D. I. McCloskey, and P. B. C. Matthews. The contribution of muscle afferents to kinesthesia shown by vibration induced illusions of movement and by the effects of paralysing joint afferents. Brain, 95(4):705748, 1972.

[15] V. Hayward and M. Cruz-Hernandez. Tactile display device using distributed lateral skin stretch. In Proceedings of the Haptic Interfaces for Virtual Environment and Teleoperator Systems Symposium, volume ASME DSC-69-2, pages 1309–1314. ASME IMECE2000.

[16] R. Johannson. Skin Mechanoreceptors in the Human Hand: Receptive Field Characteristics, pages 159–170. Sensory Functions of the Skin in Primates, with special reference to Man. Pergamon Press Ltd.,Oxford,, 1976.

[17] L. Jones, M. Nakamura, and B. Lockyer. Development of a tactile vest. In Proceedings of the 12th International Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems. IEEE,March 2004.

[18] K. J. Kuchenbecker, N. Gurari, and A. M. Okamura. Effects of visual and proprioceptive motion feedback on human control of targeted movement. In IEEE International Conference on Rehabilitation Robotics, pages 513–524, June 2007.

[19] R. H. LaMotte, M. A. Srinivasan, C. Lu, P. S. Khalsa, and R. M. Friedman. Raised object on a planar surface stroked across the fingerpad: Responses of cutaneous mechanoreceptors to shape and orientation. Journal of Neurophysiology, 80:2446–2466, 1998.

[20] V. Levesque and V. Hayward. Experimental evidence of lateral skin strain during tactile exploration. In Proc. Eurohaptics, July 2003.

[21] J. Luk, J. Pasquero, S. Little, K. E. MacLean, V. Levesque, and V. Hayward. A role for haptics in mobile interaction: Initial design using a handheld tactile display prototype. In Proc. of the ACM 2006 Con-ference on Human Factors in Computing Systems, CHI 2006, pages171–180, 2006.

[22] D. Mahns, N. Perkins, V. Sahai, L. Robinson, and M. Rowe. Vi-brotactile frequency discrimination in human hairy skin. Journal of Neurophysiology, 95:1442–1450, March 2006.

[23] Y. Makino and H. Shinoda.Selective stimulation to superficial mechanoreceptors by temporal control of suction pressure. In Haptic Interfaces for Virtual Environment and Teleoperator Systems, WorldHaptics Conference, pages 229–234, March 18-20, 2005.

[24] G. Moy and R. Fearing. Effects of shear stress in teletaction and human perception. In Proceedings of the 1998 ASME Dynamic Systems and Control Division, ASME International Mechanical Engineering Congress and Exposition, volume DSC-Vol. 64, pages 265–272, November 1998.

[25] A. Murray, R. Klatzky, and P. Khosla. Psychophysical characterization and testbed validation of a wearable vibrotactile glove for telemanipulation. Presence: Teleoperators and Virtual Environments, 12(2):156– 182, April 2003.

[26] M. Pare, H. Carnahan, and A. Smith. Magnitude estimation of tangential force applied to the fingerpad. Experimental Brain Research,142:342–348, 2002.

[27] I. Summers, P. Dixon, P. Cooper, D. Gratton, B. Brown, and J. Stevens. Vibrotactile and electrotactile perception of time-varying pulse trains.Journal of Accoustical Society of America, 95(3):1548–1558, March1994.

[28] H. Tan, R. Gray, J. J. Young, and R. Traylor. A haptic back display for attentional and directional cueing. Haptics-e, 3(1), June 2003.

[29] H. Tan, A. Lim, and R. Traylor. A psychophysical study of sensory saltation with an open response paradigm. In In Proceedings of the Ninth (9th) International Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, American Society of Mechanical Engineers Dynamic Systems and Control Division, volume 69-2,pages 1109–1115, 2000.

[30] Q. Wang, V. Hayward, and A. M. Smith. A new technique for the controlled stimulation of the skin. In Proceedings of the Canadian Medical and Biological Engineering Society Conference, CMBEC, September 9-11, 2004.