A Sense of Things

Barrett L. Dorko, P.T.  

In 1992 I did a presentation for The International Federation of Orthopedic Manipulative Therapists about the potential effect of manual care upon the therapist. I spoke of stretch activated ion channels in the therapist’s hands, reflexive effect and my personal experience of increasing sensitivity as I remained in the clinic year after year. Geoffrey Maitland, the highly respected founder of manual care in Australia , moderated the session and he addressed the 700 therapists gathered as I took my seat. “I don’t know about you,” he said, “but that was beautiful music to my ears.” I was pleased, of course, but found that many of my colleagues didn’t share Maitland’s enthusiasm, and more than a few had no idea what I was talking about. Since then we’ve learned a great deal about how tactile stimulation can alter us, teach us, and create new sensibilities. The following is an effort to explain further what I said over ten years ago.    

The Task  

Imagine being given this task. Before you is a shape of some sort and you cannot see beyond its surface. The object has a covering which is pliable to various degrees in different areas. You’re told that there is a certain, silent activity within and that the shape itself might change at any moment. Your job is to sense and interpret the internal activity while permitting a change in the shape no matter how subtle or dramatic. How would you go about accomplishing this? How would you describe what you eventually came to sense?  

The handling I do when treating patients is guided by my thoughts about the task I have described here. I am not referring to specific tests of provocation.  

The Synesthetic Experience  

A few years ago I reviewed a book entitled The Man Who Tasted Shapes by a neurologist, Richard E. Cytowic. It concerned Cytowic’s study of synesthesia, a specific neurologic phenomenon defined as “Joined sensation-the rare capacity to hear colors, taste shapes or experience other equally strange sensory fusions whose quality seems difficult for the rest of us to imagine (From Synesthesia; A Union of the Senses also by Cytowic).” In the review I said in part, “After an exhaustive study of the limbic system using various methods to highlight the releasing of its normal processes to the conscious mind, Cytowic concludes, ‘...synesthesia is a very fundamental mammalian attribute. I believe synesthesia is actually a normal brain function in every one of us, but that its workings reach conscious awareness in only a handful.’” The idea that we might all be experiencing some melding of the senses though we are not all aware of it is also mentioned in the forward to Cytowic’s first book written by neurosurgeon Ayub K. Ommaya: “After all, synesthesia is what we all do without knowing that we do it, whereas synesthetes do it and know that they do it.”  

“We don’t see with our eyes, we see with our brains.” The speaker is Paul Bach-y-Rita, a physician and neuroscientist at the University of Wisconsin . I first read of his work in the June 2003 issue of Discover magazine in an article entitled “Can you see with your tongue?” After watching his profoundly impaired father recover from a stroke that was known to have severely injured his brain tissue, Bach-y-Rita turned his attention to research designed to reveal and enhance the brain’s apparent plasticity. He developed electronic devices capable of stimulating tactile sense when a camera “saw” an object move. When the stimulation was applied to the tongue of a blindfolded subject they quickly learned to “see” with their tongue. This sounded a great deal like the production of synesthesia to me and I asked him about that in a personal communication. He replied: “I consider that what we are doing is completely different. The tongue becomes merely a relay, and no sensations are experienced on the tongue; this is much like a blind person with a long cane, who perceives the door, chair, foot, etc as being at the cane tip but feels nothing at the hand which has become the relay.” Fair enough, but in the Wiley Encyclopedia of Biomedical Engineering, he also says: “Synesthesia is the experiencing of one sense as if it were another; for example, the experience of tasting shapes, has been known for at least 300 years. When it arises unbidden and operates uncontrolled, it can be a serious and disabling pathology. Nevertheless, it leads to remarkable insights in the understanding and control of cognitive function. A controlled form of synesthesia may have parallels to the sense display unit (invented and developed in his laboratory)”  

It appears that while naturally occurring synesthesia and the neurologic adaptation induced by means of Bach-y-Rita’s training and instrumentation are not precisely the same, the difference is primarily that of control and the end result, the translation of one sense to another, is much the same. The lack of simultaneous experience, i.e. the blind person has no sense of their hand, may be at the root of its distinction from the naturally occurring condition.  

Can You See With Your Hands?  

Bach-y-Rita has proven that it is possible to create a controlled form of synesthesia with enough of the proper training. The implications for rehabilitation are enormous and for this he was awarded the Coulter Award from The American Congress of Rehabilitation Medicine in 2002.  What I’m proposing here is that manual care often does this as well. In the clinic synesthesia is created by prolonged manual contact combined with verbal feedback from the patient concerning the nature of their sensory response. The therapist is certainly blind to the inner activity of the patient, and, the information they gather regarding the location of the mechanical and reflexive effect of their handling would be processed by the therapist’s brain in much the same way the blind person learns to create internal images once given a little practice and feedback.  

For many years I have employed what I call Simple Contact, a method of manual care that gently makes the patient aware of their inherent self-correction, also called ideomotor activity, and allows its fullest expression. This handling does not involve coercion, direction or provocation and the therapist exerts a pressure designed to do no more than slightly deform the patient’s skin. I typically maintain a distinct stillness after I’ve landed somewhere with my hands and focus my attention on the patient’s response. I’m referring here to their reflexive reaction some distance from my contact. Long ago I noticed that I could tell where the patient sensed their changing (feelings of warmth, internal movement of one sort or another and alterations in symptoms) before they told me. This began to occur after asking many times, “What are you feeling and where?” I began to know where they would describe their change because, well, I was getting an image in my head. Often this was a distinct impression of the body part though often it was not quite as clear as that. I still check my accuracy several times with every patient during the course of any treatment but long ago concluded that I had somehow acquired this odd ability. It has never been what I would call infallible. My sense of things as I employ Simple Contact is an unintended consequence of my method and technique. As you might imagine, the dialogue it generates with the patient can be quite useful.  

Bach-y-Rita’s work and the theories regarding the nature of synesthesia provide a theoretical explanation for the images in my head. I wouldn’t have predicted that this would happen but, knowing what I now know, it makes sense that it would. After all, a blind person acquires a sense of their environment in the same way I gained a sense of my patient’s internal activity. Neither one of us can see what it is we sense in the usual manner but instead extract a meaning from tactile stimulation that is reinforced by repetition and reliable feedback. No one questions the blind person’s ability to do this-why wouldn’t it happen to me?   

Bach-y-Rita suggests that the central processes involved in the acquisition of this skill include glial cell activity. The free-floating, nonelectrical neurotransmitters now known to emanate from the glia, he believes, would constitute the necessary mechanism for the learning displayed by his subjects. Such a model is rapid and more energy efficient than the synaptic model commonly used in learning theory. This sort of learning is also known as “unconscious integration” or “implicit learning,” meaning that the acquisition of knowledge takes place largely independent of the learner’s awareness of either the process of learning or of the knowledge ultimately attained. The “controlled synesthesia” enables the extension of sensibilities by providing the user with new senses. Since the therapist adapts sensor data passing through their hands, it should be possible for them to experience the data stream by direct experience of perception. As discussed in the preceding section, what the mind abstracts from the hand is the meaning of the data stream rather than the data points themselves. Sensory information registered without awareness in this way is known as blindsight. Such unconscious integration is much faster than interpreting data by conscious cognition. As for the manner in which the therapist experiences this, a quote from David Bohm’s Wholeness and the Implicate Orders seems relevant to me: “…thought itself is an actual process of movement. That is to say, one can feel a sense of flow in the stream of consciousness not dissimilar to the sense of flow in the movement of matter in general.”


Finally, I want to speak of the task I described at the beginning of this essay. I was, of course, describing a human body. Perhaps it would better to state the answer about handling in terms of what a therapist wouldn’t do in an effort to sense the internal activity while permitting spontaneous change. They wouldn’t rub, poke, prod, coerce, grip or control with their hands. The hands would instead be used as a primary sensory organ, now known to be fully capable of sensing the patient’s movement and leading the therapist’s brain to a new sense of the activity before them. This sense of the patient’s internal activity, in my opinion, will not mature when the therapist’s hands are busy doing the things previously listed, and therapists practicing in that manner will always wonder at the sensibilities I have acquired. The technique of Simple Contact will make this sense possible.  

Geoffrey Maitland knew what I was talking about, and now perhaps others will come to understand it as well.  

Suggested reading:  

Bach-y-Rita, Nonsynaptic Diffusion Neurotransmission and Late Brain Reorganization, New York : Demos-Vermande, 1995.  

P. Bach-y-Rita, Volume transmission and brain plasticity, Evolution and Cognition, 8: 115-122, 2002