Through more than 38 years, Per Gjeding has developed and refined the treatment concept PAS^® (Proprioceptive Activation System). The PAS^® concept aims at guiding the client, suffering from pain or dysfunction of the Musculoskeletal System – into activating the proprioceptive sense. The treatment re-establishes the right connection between the brain stem, pons, the cerebellum and the cerebral cortex (from here on only cortex). This enables the cortex to take over control of the Musculoskeletal System.

Proprioception is the process that enables the body to vary muscle contractions as immediate response to incoming information about outside influences. The muscle initiation is mediated through stretch receptors which supply information on the joint positions of the body.

The sensing of joint movement (proprioception) and acceleration (kinesthetic) are the sensory feedback mechanisms for movement control and posture. These mechanisms are used in conjunction with the vestibular system (the liquid filled network in the inner ear, registering the effect of gravity and keeping the body informed and in balance) by the brain to infer constant sensory input from the surroundings.

When the proprioceptive sense is well functioning, we continuously adjust our body position. This sense helps us to take optimal position in a chair, to hold on to tools like a fork or a pencil in the right way and to estimate how to move through a room without bumping into things. If the system does not function properly, one has to keep focus on things which should work automatically. For instance one may have to use sight to adjust one’s position.

The PAS^® concept operates with a number of trigger points, functioning as access points to activating areas under the brain’s control:

1. The linkage between the big toe and thalamus: By examining the big toe’s ability to yield resistance and relax, a Golgi-tendon activation of thalamus is performed, whereby the muscles reopen for communication between the cerebellum and cortex.
2. The linkage between the inside of the thigh and the autonomous nervous system: Through an activation of the Golgi-tendon organs of the inside of the thigh/ the abductor group, hypothalamus is activated. The hypothalamus controls many functions: temperature, hormones, metabolism, thirst, hunger, sexual behavior, anxiety, anger and various rhythms of activity. In connection with PAS the focus is primarily on the linkage to the autonomous nervous system and on hormonal response.
3. The communication trigger point: When the head is bent forward and then slowly “back in place”, as when saluting obediently, the brain stem, pons, is activated. This enables communication between the cerebellum and the cortex. Then the muscular movements are controlled by will, naturally and correctly.
4. The linkage between sound and energy: When sound is made in connection with movement, the pituitary gland is activated. This subsequently stimulates mitochondria in the muscles cells to release energy to the brain which is used in the PAS treatment. This linkage is also utilized in the specially developed exercise program of an hour’s length. The exercise program is a thorough workout of the  entire body aiming at a well working connection between brain and body.
5. The anxiety linkage: Should a patient experience a whiplash lesion, shock and concussion, the connection between the limbic system and the cortex is blocked. This results in a lack of ability of the cortex’ rational array of the anxiety, often felt as a consequence of traumas. Through PAS treatment the connection is re-established. Additionally it has been proven as a pivotal part of the recovery process when the PAS specialist corrects the anxiety provoking stories and traumas that the client is often contained in.

A substantial amount of patients present dysfunctions that have their origin in an unnoticed and untreated whip lash lesion which may have happened 10, 20 or 30 years or longer back in time.

A whip lash lesion can be conceived as a straining of the brain stem prohibiting proper communication and thereby control with the body. This inhibition of such a central communication pathway causes so severe disturbances of the brain stem that a movement can no longer be carried out purposely by the cortex. This subsequently results in a degree of disablement and dysfunctional disturbances. The movements which are nevertheless carried out are reflex movements, activated through the cerebellum. With a whip lash lesion there are dramatic communication disturbances between the brain stem, the cortex, the encephalon, the cerebellum and the sensory cell ganglia and the periphery nerve’s contact with the gray matter of the spinal cord. As previously eluted to, these functions are pivotal for the body to maintain and balance. Consequently when the cannot carry out a movement without locking the joints in the back, due to the severed communication between Golgi-tendon organs and the cerebellum. This results in reduced efficiency because the speed at which the impulse is delayed to the arms and legs has been decreased. Reaction speed is significantly decreased which causes many complications in everyday life, just as one becomes more prone to industrial injury.

With any kind of pain in the body, the sympathetic nerves and the encephalon are shut off (by thalamus) which disables the motoric center in the cortex to be activated. The back muscles are after whip lash damage in tonic tension, and the big trapezius in particular, which is involved in holding the head, is very tense. Therefore the back muscles of patients with whip lash damage do not function correctly in functions like carrying, protecting, moving and energizing. Instead of alleviating the joints, their dysfunction increases the load to the joints alongside a dislocation of the backbone. That initiates a chain of events, again disturbing impulses to the cerebellum which constantly monitor the equilibrium and balance of the body. The imbalance is communicated to the encephalon which re directs the sensory messages to the cortex and prevents the motoric movements to be carried out properly. This is felt by the patient as muscle fatigue and reduced muscle function.

The imbalance in the back bone also affects the nervous system radiating from the spinal cord itself. The nerve roots, radiating from the back and taking care of the body’s functions, will be in a state of compression. Depending on the nerves that are affected, a dysfunction of the respecting areas of the body will occur.