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  • #16
    Originally posted by Luke Rickards View Post
    It is very well documented that the pressure of massage has an inhibitory effect on motor neurons. This is easily measured via the Hoffman reflex test. Different intensities and frequencies of pressure have been shown to produce different degrees of tone inhibition. Check out the paper attached
    Right, but I'm talking about a primary excitatory response (the twitch), not an inhibitory one. The tone inhibition happens well after the twitch is observed (from a few seconds up to a few minutes later). And the technique I'm describing to elicit the LTR is not analagous to the petrissage used in that H-reflex paper. The stimulation is brief and probably causes a small stretch, but does not involve the kind of pressure or duration of touch used in that study. I found this part of the discussion section interesting, though:

    "The role of these cutaneous mechanoreceptors in the depression of the
    H-reflex during muscle stretching was also examined and subsequently refuted by several authors. They concluded that the inhibitory response to muscle stretch was mediated primarily by the activity of secondary muscle spindle afferents. Belanger et all have also suggested that the reduction in H-reflex amplitude observed during their interventions (muscle stretching, muscle tapping) could be mediated by muscular mechanoreceptors (golgi tendon organs, muscle spindles)."

    Could these muscular mechanoreceptors initiate both an excitatory and inhibitory response with the span of a minute or two?

    The LTR has been shown to be a particularly unreliable diagnostic characteristic of MTrPs and is no longer considered essential in making the diagnosis. In their recent review, Tough et al. (2007) reported that only 28% of trials on MPS have explicitly used it.
    Yes, but the Travell/Simons way of eliciting the LTR is snapping palpation and this requires a few specialized skills like finding a taut band, putting the muscle into a precise lengthened position, and then doing the snapping thing. The dry needling studies have a much higher reliability of eliciting the LTR. That the LTR exists is not in question for me. It's why.

    This remains to be demonstrated. If an LTR can be produced under both conditions, perhaps it doesn't make a difference.
    The question I asked David Simons, who has probably snapped over more taut bands than anyone else, was: have you ever initiated a therapeutic response with snapping palpation? He said no.

    Comment


    • #17
      Originally posted by Luke Rickards View Post
      So the next question would have to be; How is the mechanoreceptor sensitivity produced and maintained? The answer must also consider this --
      Good resource Luke - I hadn't found that one yet. Your hunting instinct is extraordinary

      I'm still trying to digest what that abstract said. I really like the term 'reflex overcorrections' to describe this sensitive mechanoreceptor.

      Comment


      • #18
        Hi Kim,

        I'm afraid you are confusing me a little now.

        You are looking for a mechanism for the LTR -- This mechanism is interesting to you because it might help explain why the technique you use, which elicits this response, results in decreased tone post-treatment -- Decreased tone is therapeutic.

        BUT, you argue that other methods of eliciting a LTR are not therapeutic.

        Thus, there are either two or more mechanisms that cause a LTR OR the LTR has nothing to do with the therapeutic effect.

        Also, the technique you are using might look very different to others studied in relation to H-reflex inhibition, however, you can only assume that it doesn't affect this arc in any way. What if it does?


        All this will have to be tied to fascial contractility eventually. The mechanism leading to MFB contractility doesn't appear to be SNS innervation. Hinz and Gabbiani (2003) make it clear that differential expression of SM-actin by MFBs depends on mechanical stress, a process common in wound healing. However,
        loss of mechanical stress seems to be an important signal for differentiated myofibroblasts to de-differentiate and/or disappear. At the end of normal wound healing the ECM is re-constituted and again takes over the mechanical load, thereby releasing embedded myofibroblasts from stress. At this time most myofibroblasts are removed by apoptosis from the wound granulation tissue.
        So, in relation to MTrPs, some kind of perpetuating factor must be present that maintains MFB SM-actin expression. Increased mechanical stress might be present under muscle spindle activity, however, "fusimotor neurons (can't) be selectively activated to produce spindle sensitization and stretch reflex reinforcements."

        What other mechanisms of mechanoreceptor sensitivity might be implicated?
        Last edited by Luke Rickards; 10-11-2009, 04:42 AM.
        Luke Rickards
        Osteopath

        Comment


        • #19
          Originally posted by Luke Rickards View Post
          I'm afraid you are confusing me a little now.
          I'm confused as well - and it might get even more confusing before it makes sense - lets proceed at any rate.

          You are looking for a mechanism for the LTR -- This mechanism is interesting to you because it might help explain why the technique you use, which elicits this response, results in decreased tone post-treatment -- Decreased tone is therapeutic.
          BUT, you argue that other methods of eliciting a LTR are not therapeutic. Thus, there is either two or more mechanisms that cause a LTR OR the LTR has nothing to do with the therapeutic effect.
          Yes, the mechanism in dry needling and in my technique appear to have a therapeutic effect, but both are done in a neutral/shortened position. I don't think that the twitch itself causes the therapeutic effect directly. I think it may be that a wave is propagated by the twitch that secondarily stimulates other mechanoreceptors (I'm thinking Pacinian corpuscles here) to cause the inhibition.

          I've observed the twitch often, but not always, when decreased tone ensues. But I always propagate a wave, whether or not the twitch occurs. I think that snapping palpation in a lengthened position would not propagate such a wave, or that it would be terminated rather quickly (too much tension to create a long-lasting wobble)

          What I was trying to say earlier is that the LTR exists and may be indicative of a separate phenomenon that occurs from a primary mechanism other than a contraction knot. I'm looking for something that would account for all of the findings in the vicinity: 1) a contraction knot 2) a reflex overcorrection and 3) compression of both local and traversing nerves (referred pain). And I keep coming back to a restricted perimysial tunnel. Now whether or not that tunnel restriction is created by fascial contraction is very speculative. I'm happy to ditch the whole fascial contraction idea if we could explain how this perimysial tunnel syndrome comes to be.
          Last edited by Kim LeMoon; 15-01-2008, 05:09 PM. Reason: missed a word

          Comment


          • #20
            Kim,
            I'm happy to ditch the whole fascial contraction idea if we could explain how this perimysial tunnel syndrome comes to be.
            Have you ruled out nervi nervorum and vasa nervorum disturbance due to mechanical stresses?
            Diane
            www.dermoneuromodulation.com
            SensibleSolutionsPhysiotherapy
            HumanAntiGravitySuit blog
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            @dfjpt
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            "Rene Descartes was very very smart, but as it turned out, he was wrong." ~Lorimer Moseley

            “Comment is free, but the facts are sacred.” ~Charles Prestwich Scott, nephew of founder and editor (1872-1929) of The Guardian , in a 1921 Centenary editorial

            “If you make people think they're thinking, they'll love you, but if you really make them think, they'll hate you." ~Don Marquis

            "In times of change, learners inherit the earth, while the learned find themselves beautifully equipped to deal with a world that no longer exists" ~Roland Barth

            "Doubt is not a pleasant mental state, but certainty is a ridiculous one."~Voltaire

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            • #21
              Originally posted by Diane View Post
              Have you ruled out nervi nervorum and vasa nervorum disturbance due to mechanical stresses?
              I've included both of them as an essential ingredient in my explanation of how a restriction could generate ischemia, hypoxia and pain. What I'm stuck on is - what is causing the mechanical stress? You know more about tunnel syndromes than I do. Any thoughts?

              Comment


              • #22
                [/QUI've included both of them as an essential ingredient in my explanation of how a restriction could generate ischemia, hypoxia and pain. What I'm stuck on is - what is causing the mechanical stress? You know more about tunnel syndromes than I do. Any thoughts?
                I think, in order to understand anything, it's essential (at least it was to me) to understand the difference between mesodermal derivatives and ectodermal derivatives, particularly in terms of oxygen demand.

                1. Streidter says in his book Principles of Brain Evolution, that the nervous system/ectoderm (brain, spinal cord, nerves, outer layer of skin) comprises only 2% (even though our brains are 5 times bigger than they need to be (!) to operate a mammal our size) of the entirety of the body.... but uses 16-20% of all the oxygen.

                2. Mesodermal derivatives (everything else) comprise 98% of the physicality of the body but only use 80% of the oxygen taken in.

                Right there, we can see that the nervous system is high maintenance, relatively.

                Next we should consider physical morphology. I read a quote by Nolte, a neuroanatomist, in the Encyclopedia of the Human Brain about this: he says, if you made the cell body of a neuron the size of a tennis ball, the dendrites would fill a room, and the axon would extend a half mile and would be the size of a garden hose.

                Obviously, this is a huge amount of surface area. And a huge amount of potential vulnerability.

                The only way this thing gets fed is by being plugged into at intervals by the vasa nervorum.

                The Clinical Neurodynamics book by Michael Shacklock has nice pictures of mechanical stessors. Butler's first book, from 1991 (Mobilization of the Nervous System), has great images of the insides of nerves and how they are fed.

                First, picture a nerve tunneling through mesoderm. It's essentially a very long round cylinder, sort of a cable of other thin fine cylinders, like a fibre optics cable, suspended three dimensionally such that the pressure or tug on it is evenly distributed. The fibres of the nerve (unlike fibre optics fibres) are highly alive and busy, needing large supplies of oxygen. The blood supply to the nerve is redundant and slack, for the most part, because nature has made it a priority to feed nerves.. the blood supply comes in on all sides of the nerve.

                Should there not be enough movement in the entirety of the body to reinforce the equilibrium, or should there a mechanical distortion to a cable, either sudden force (injury) or long term (habits of sitting too long in one position, maybe with a favorite leg crossed, let's say), mechanical stress could occur, leading to a situation whereby one side of the nerve is still slack and being fed, but blood supply to another side becomes taut and therefore unable to feed the nerve. Result: nervi nervorum nociceptive fibres signal spinal cord.

                Another consideration is, there are no lymphatics in nerves. Even if enough O2 were able to get in to keep the nerve happy, removal of waste (from these busy, productive, neurochemically secreting cells) in a timely and sufficient manner might become impaired, leading to back up/swelling inside the neural container. This would become yet another form of not just mechanical but also chemical stress. Result: nervi nervorum nociceptive fibres signal spinal cord.

                Mechanical stress of nerves very quickly merges into physiological changes of a detrimental sort.

                This is just off the top of my head - I'm sure there's far more to it than this.
                Diane
                www.dermoneuromodulation.com
                SensibleSolutionsPhysiotherapy
                HumanAntiGravitySuit blog
                Neurotonics PT Teamblog
                Canadian Physiotherapy Pain Science Division (Archived newsletters, paincasts)
                Canadian Physiotherapy Association Pain Science Division Facebook page
                @PainPhysiosCan
                WCPT PhysiotherapyPainNetwork on Facebook
                @WCPTPTPN
                Neuroscience and Pain Science for Manual PTs Facebook page

                @dfjpt
                SomaSimple on Facebook
                @somasimple

                "Rene Descartes was very very smart, but as it turned out, he was wrong." ~Lorimer Moseley

                “Comment is free, but the facts are sacred.” ~Charles Prestwich Scott, nephew of founder and editor (1872-1929) of The Guardian , in a 1921 Centenary editorial

                “If you make people think they're thinking, they'll love you, but if you really make them think, they'll hate you." ~Don Marquis

                "In times of change, learners inherit the earth, while the learned find themselves beautifully equipped to deal with a world that no longer exists" ~Roland Barth

                "Doubt is not a pleasant mental state, but certainty is a ridiculous one."~Voltaire

                Comment


                • #23
                  The dry needling studies have a much higher reliability of eliciting the LTR.
                  Under these circumstances the LTR is not diagnostic; it is an epiphenomenon of treatment, since the diagnosis has already been made and location decided. Since the LTR is generally unreliable, this might always be the case. It is possible that direct mechanical disruption from the needle point is sufficient alone to cause a LTR in many areas. For example, I can consistently produce a LTR in the masseter, ext. digitorum brevis, foot and hand 1st dorsal interosseous, upper trapezius and infraspinatus muscles in the the absence of any characteristics of MTrPs.
                  the mechanism in dry needling and in my technique appear to have a therapeutic effect, but both are done in a neutral/shortened position. I don't think that the twitch itself causes the therapeutic effect
                  I have been doing dry needling for 9 years now and I have seen plenty of twitch responses when needling in a lengthened position. Like you, I have not observed a strong relationship between the presence of the LTR and therapeutic outcomes.
                  a wave is propagated by the twitch that secondarily stimulates other mechanoreceptors (I'm thinking Pacinian corpuscles here) to cause the inhibition
                  There is strong indication that the deep, spreading sensation during needling is the result of mechanotransduction prorogation through the connective tissues from grasping and winding of the CN around the needle, which will more likely lead to inhibition than a brief, and unreliable, LTR (I have pictures of this if you want to see them).


                  Now whether or not that tunnel restriction is created by fascial contraction is very speculative. I'm happy to ditch the whole fascial contraction idea if we could explain how this perimysial tunnel syndrome comes to be.
                  As you see, Diane is the expert when it comes to peripheral nerve sensitisation, which I think is a reasonable initiating event for "MTrP phenomena" (if we want stick to this term). Using this as a starting point does not preclude the eventual involvement SM-actin expressing MFBs under the influence of local mechanical strain that might result from affected motor neurons or local inflammation (sub P etc), for example.

                  Vasomotor disturbance of the vasa nervorum that Diane mentioned might be interesting for you to delve into, since this is obviously affected by sympathetic tone.
                  Last edited by Luke Rickards; 15-01-2008, 10:31 PM.
                  Luke Rickards
                  Osteopath

                  Comment


                  • #24
                    I have never bothered worrying about twitches, be they local or generalized. I often have twitches myself, usually at the moment of falling asleep. I wouldn't know if they are "local" or general - they just are. I think they are centrally induced.

                    About mechanoreceptor information in one place spreading to mechanoreceptors in another, Gandevia is the guy who has looked into it. He analyzed Achilles heel cord reflex, carefully measuring mechanoreceptors in tendon, muscle and skin. He found that they all three fire with a strike on the A. tendon. His work makes sense to me, because he includes skin mechanoreceptors, not just ones in muscle. He says he thinks that a monosynaptic reflex arc is anything but.

                    It makes sense because
                    1. the skin layer (in its privileged position on the outside of the body) is the first layer contacted by an exteroceptive agent (like a therapist);
                    2. it has lots of mechanoreceptors of all sorts, fast adapting, slow adapting, large myelinated (Aα), small(er) myelinated (Aϐ), etc.
                    3. the outer layer of skin with all its various receptive array is made of ectoderm, same as brain and spinal cord and nerves are... skin is like the outside of the brain. See post 22 about the difference between ectodermal derivatives and mesodermal derivatives. One (mesoderm) is "connective" and structural, the other (ectoderm) is communicative, barely there structurally but highly functional.

                    Without a way to remove skin completely to test deeper mechanoreceptors without skin being a confounding factor, one has to account for it, and for any influence it may exert of behavior of anything else going on in there. So (I thought to myself ages ago), why not make an hypothesis that says that skin tells the brain what's going on, then other things deeper in may be stimulated mechanically by a therapist's hands, or neurologically by descending adaptation from CNS? It accounts for more variables and is therefore a simpler hypothesis, at least I think Occam would like it better.
                    Last edited by Diane; 16-01-2008, 02:11 AM.
                    Diane
                    www.dermoneuromodulation.com
                    SensibleSolutionsPhysiotherapy
                    HumanAntiGravitySuit blog
                    Neurotonics PT Teamblog
                    Canadian Physiotherapy Pain Science Division (Archived newsletters, paincasts)
                    Canadian Physiotherapy Association Pain Science Division Facebook page
                    @PainPhysiosCan
                    WCPT PhysiotherapyPainNetwork on Facebook
                    @WCPTPTPN
                    Neuroscience and Pain Science for Manual PTs Facebook page

                    @dfjpt
                    SomaSimple on Facebook
                    @somasimple

                    "Rene Descartes was very very smart, but as it turned out, he was wrong." ~Lorimer Moseley

                    “Comment is free, but the facts are sacred.” ~Charles Prestwich Scott, nephew of founder and editor (1872-1929) of The Guardian , in a 1921 Centenary editorial

                    “If you make people think they're thinking, they'll love you, but if you really make them think, they'll hate you." ~Don Marquis

                    "In times of change, learners inherit the earth, while the learned find themselves beautifully equipped to deal with a world that no longer exists" ~Roland Barth

                    "Doubt is not a pleasant mental state, but certainty is a ridiculous one."~Voltaire

                    Comment


                    • #25
                      Originally posted by Luke Rickards View Post
                      grasping and winding of the CN around the needle...(I have pictures of this if you want to see them).
                      Are you referring to Helene Langevin's work?

                      Vasomotor disturbance of the vasa nervorum that Diane mentioned might be interesting for you to delve into, since this is obviously affected by sympathetic tone.
                      Thanks Luke, this at least fits in with my notion that the whole TrPt phenomenon starts (and is maintained) by autonomic dysregulation. I was mistaken that myofibroblasts contraction was under (direct) autonomic control. I'm going to let all of this stew and search around here for more information on how the vasa nervorum works. My understanding is pretty simplistic right now.

                      Comment


                      • #26
                        Originally posted by Diane View Post
                        I have never bothered worrying about twitches
                        I won't either then. From what you and Luke have said, I'm satisfied that twitches don't mean a whole lot to my theory.
                        I'll look into Gandevia's work too.

                        So (I thought to myself ages ago), why not make an hypothesis that says that skin tells the brain what's going on, then other things deeper in may be stimulated mechanically by a therapist's hands, or neurologically by descending adaptation from CNS?
                        I'm in agreement with your hypothesis regarding the skin's role in the mechanisms of manual treatments. My hypothesis, however, is not addressing treatments. It's an attempt to explain a particular phenomenon in a more logical way than the theories that are currently espoused. I'm getting clearer on what I know and don't know and at best, my paper will give others a fresh look at an old idea. You and Luke have given me more than enough to consider for the moment.

                        Comment


                        • #27
                          Are you referring to Helene Langevin's work?
                          Yep.
                          Luke Rickards
                          Osteopath

                          Comment


                          • #28
                            Originally posted by Diane View Post
                            I often have twitches myself, usually at the moment of falling asleep. I wouldn't know if they are "local" or general - they just are. I think they are centrally induced.
                            i remember david butler saying that he considered twitches to a reset from the SNC

                            btw, Diane, very nice analogies/images in your post#22. I posted it to my blog.
                            Last edited by pht3k; 18-01-2008, 05:45 AM.
                            physiotek.com ------ __@
                            Eric aka pht3k ---- _`\<,_
                            ----------------- (*)/ (*)

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                            • #29
                              Hi pht3k,
                              Glad you liked them - nice blog. I like Ramachandran.
                              Diane
                              www.dermoneuromodulation.com
                              SensibleSolutionsPhysiotherapy
                              HumanAntiGravitySuit blog
                              Neurotonics PT Teamblog
                              Canadian Physiotherapy Pain Science Division (Archived newsletters, paincasts)
                              Canadian Physiotherapy Association Pain Science Division Facebook page
                              @PainPhysiosCan
                              WCPT PhysiotherapyPainNetwork on Facebook
                              @WCPTPTPN
                              Neuroscience and Pain Science for Manual PTs Facebook page

                              @dfjpt
                              SomaSimple on Facebook
                              @somasimple

                              "Rene Descartes was very very smart, but as it turned out, he was wrong." ~Lorimer Moseley

                              “Comment is free, but the facts are sacred.” ~Charles Prestwich Scott, nephew of founder and editor (1872-1929) of The Guardian , in a 1921 Centenary editorial

                              “If you make people think they're thinking, they'll love you, but if you really make them think, they'll hate you." ~Don Marquis

                              "In times of change, learners inherit the earth, while the learned find themselves beautifully equipped to deal with a world that no longer exists" ~Roland Barth

                              "Doubt is not a pleasant mental state, but certainty is a ridiculous one."~Voltaire

                              Comment


                              • #30
                                Originally posted by pht3k View Post
                                i remember david butler saying that he considered twitches to a reset from the SNC
                                I'm not familiar with the abbreviation SNC. CNS makes more sense in this context, is that what you mean? Can anyone point me to Butler's mention of twitches. I said I'd let it go, but the twitch is still curious to me and I'd like to learn more.

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