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PAIN . Perception. What hurts more?. PERCEPTION . Two senarios. Perception of pain . “what determines the volume level of symptoms, how is it that some people amplify their symptoms, and others de amplify them?” Do some individuals “amplify” their symptoms?
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PERCEPTION • Two senarios
“what determines the volume level of symptoms, how is it that some people amplify their symptoms, and others de amplify them?” • Do some individuals “amplify” their symptoms? • Does amplification reflect the fact that patients have different explanatory models for understanding the significance of their pain?
What do we think causes pain? • Tissue damage • Posture & muscle imbalances
Nociception • Nociception is the process by which intense thermal, mechanical or chemical stimuli are detected by a subpopulation of peripheral nerve fibers, called nociceptors • Their high threshold differentiates nociceptors from sensory neurons
Nociceptors are excited only when stimulus intensities reach the noxious range • located in the dorsal root ganglia (DRG) for the body and the trigeminal ganglion for the face.
Noxious stimuli • An external or internal physical change that induces afferent input in the nervous system, with or without sensory experience or a behavioral response. A noxious stimulus is actually, or potentially, damaging to tissue and liable to cause pain, but does not invariably do so
Nociception is simply a sensory signal indicating potential harm. Pain is a conscious experience, and whether nociception ends up being perceived as pain depends on many more factors.
Because phantom limb pain feels so real, it is reasonable to conclude that the body we normally feel is subserved by the same neural processes in the brain; these processes are normally activated and modulated by inputs from the body, but they can act in the absence of any inputs
Postural Structural Biomechanical Model • Misalignments can “impose excessive stress on the spine leading to degeneration/damage or dysfunction and eventually to painful back conditions • In this model, the imbalances and symmetries increase the abnormal mechanical/physical stresses imposed on the musculoskeletal system. This may lead recurrent injury or the development chronic conditions through a gradual process of wear-and-tear
“does it really matter if these PSB factors or minor control changes exist and would they cause some catastrophic failure in the musculoskeletal system?”
“the spine can undergo profound physical changes that are well tolerated without the development of a symptomatic condition.”
Biological reserve allows for such losses without a negative effect on spinal function or the development of a condition. • The system is capable of tolerating and compensating for these factors within the available surplus.
Trunk stabilization is achieved by what level of contraction? • Add 32 kg weight to the torso- now what?
Muscle Imbalances? • “whether insufficient or excessive, a deviation from optimal extensibility is thought to precipitate unusual wear and tear on capusular structures and articular surfaces of involved joints. It is suggested that deviations from optimal extensibility contribute to muscle imbalances, faulty posture, and dysfunctional movement. Although guidelines for what constitutes insufficient, optimal, and excessive extensibility measurements are based on the science of kinematics, their clinical validity has rarely been studied.
alterations of the pain pathway lead to hypersensitivity, such that pain outlives its usefulness as an acute warning system and instead becomes chronic and debilitating • http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2852643/
Nociceptive pain is an adaptive alarm system, persistent pain is maladaptive • Essentially an ongoing false alarm
Net Effect: recruitment of previously subthreshold inputs to cause pain • Produces pain hypersensitivity
Allodynia • Hperalgesia
Fear avoidance • “higher fear avoidance, sensory pain, anxiety, depression, disability, and response to pain provocation test. This group demonstrated a greater likelihood of having allodynia (pain in response to non noxious stimuli) and was judged to have a dominant psychosocial component to presentation”