ABSTRACT
Reflex deficits cause movement disorders
Reflexes execute muscle memories. Those allocated to stabilize balance and limb positions can become deficit, fail to do their job, or even be the cause of instability and thereby movement disorders. Muscle memories may be improved with practice. Restore them to former or even superior performance and mitigate movement disorders.
Movement disorder symptoms can be compensatory measures including irregular posture, defensive movements, avoidance of tasks, dependency on people and devices, diversion of cognitive resources, and modified behavior. People, consciously, or automatically do what is necessary to mitigate the effects of systems gone awry. It is the way the organism is designed.
Key takeaways
- Stabilization systems automatically countervail forces that would perturb balance and intended limb positions
- Deficit stabilization systems cause movement and cognitive disorders
- Stabilization systems are reflexes that execute muscle memories
- All muscle memories may be improved or restored with practice
- Muscle memories are cellular structures determined by cell epigenomes
- Reflexes are effectuated by stimulating reflex sensory neurons the way they are designed to be stimulated
- Most symptoms are compensatory measures taken to mitigate the effects of deficit reflexes
- Compensatory measures can become an alternative norm
NARRATION
Stabilization systems exist to automatically maintain normal or superior balance and movement
Balance reflexes countervail forces that would cause imbalance. Joint stabilization reflexes countervail forces that would unintentionally move limbs off target positions.
They use closed loop mechanisms that sense and respond to unintentional perturbations. There are many manmade examples of such systems. For example, battleship guns are mounted on stabilized platforms that isolate them from the movement of the ship. Whereas the ship may pitch, roll, yaw, and move in response to wind and shifting weights, the platform does not. Sensors detect the ship movement and actuators attached to the platform produce forces that countervail the ship movement.
In this manner, aiming the gun is greatly simplified as it is mounted on a stable rather than a moving platform. So it is with buildings that are stabilized against earthquakes, active suspension systems that stabilizes an automobile against variations in road surface, and reflexes that stabilize balance and joints against unintended movement.
Stretch reflexes stabilize limb positions
Limbs are maintained in a stable and ready to respond state by opposing muscles that alternately contract causing the limb to oscillate about a target position. When a limb is involuntarily moved, a stretch reflex is triggered. One muscle is stretched and the sensory neurons, muscle spindles, within it transmit signals to the central nervous system. They, in turn, synapse with a motor neuron that contracts the stretched muscle returning the limb to the target position. Delay between sensing the stretch and completion of the movement causes overshoot which causes the opposing muscle to stretch triggering a stretch reflex in the opposite direction. The oscillation about the target position is tremor. Normal tremor is hardly perceivable, large tremor is problematic and often simply referred to as tremor.
Vestibular reflexes stabilize balance
Balance is maintained by a hierarchy of vestibular reflexes in response to sensors that detect imbalance and cause muscle contractions to restore balance. They use the same pathway and effectors in a similar manner as the stretch reflexes, the principal difference being the sensory neurons.
Deficit stabilization systems can fail to do their job and worse yet, be the cause of destabilization
Whereas tremor indicates the limb stabilization system is working, a larger than normal oscillation indicates system defects. Defective tremor not only fails at countervailing unintended movement but becomes a source of it. Instead of stabilizing limbs it may cause limbs to excessively oscillate and that interferes with fine and gross motor skills, and voluntary movement. One may question whether tremor is an effect or cause of movement disorders
Defective reflexes can exasperate rather than prevent instability
Deficit stabilization adversely affects all movement. It causes widespread side effects like Parkinsonian symptoms including the reallocation of cognitive resources.
Deficit stabilization causes movement disorder symptoms
The same neurons, proprioceptors, and effectors used for stabilization are used to plan and execute voluntary movement. It should come as no surprise that deficits, especially in proprioceptors, adversely affect voluntary movement.
Proprioceptors affect all movement
For more on proprioception – Proprioception deception
No reflex stands alone
For example, A person steps on a tack causing a withdrawal reflex that contracts muscles to remove the foot to avoid further injury and causes extensor reflexes in the contralateral limb to carry the extra load. Limb movement causes a shift in the center of gravity and its relationship with the base of support. That triggers multiple balance reflexes. As limbs are moved, multiple stretch reflexes are effectuated.
Whereas each reflex may appear to be independent, it is integral to a system of reflexes that senses and responds to equilibrium perturbations. A deficit in any single reflex can adversely affect the performance of other reflexes.
Deficit in one reflex can affect system equilibrium
Deficit reflexes can be restored or improved beyond former performance levels
How? The short answer is that deficit muscle memories cause deficit movement.
Restore the memory and fix the movement
The medical establishment is likely to reject the hypothesis that reflexes are not “hard wired”, but plastic and they execute specific muscle memories.
Stabilization reflexes execute muscle memories
A reflex is the automatic execution of muscle memories in response to stimulation of sensory neurons.
Muscle memories
Muscle memory is generally described as a voluntary movement that improves and becomes more automatic with practice. A person decides to execute the movement. Reflex muscle memories are not caused by conscience decision; they are effectuated by and respond to stimulus of sensory neurons. Therefore, to execute reflex muscle memories, one must stimulate reflex sensory neurons and that can only be done endogenously by:
Stimulate sensory neurons, the way they are designed to be stimulated
For more on Sensory Neuron Stimulation
Muscle memory is retained in cellular structures, the arrangement of proteins determined by epigenomes. The cells do what they are structured to do. But epigenomes, and thereby structures, are plastic. They adapt to the environment and respond to modulation.
Cells do what they are structured to do
For example, whereas reflexes are automatic, they respond to cognitive modulation. Reflexes can be denied, delayed, anticipated, initiated, and intensified by cognitive decision. Another example of modulation is when adrenalin release is increased, muscle response to motor neuron stimulation is increased by supercharging the delivery of oxygen and blood sugar to the muscle.
Cell performance may be modulated
Like any muscle memory, reflex muscle memories may be improved with practice. Training by subjecting them to repetitive stimulus, environmental conditions, and heightened demands with intent to improve, increases efficiency, accuracy and automaticity, changes that are remembered, changes that are enhanced muscle memory, changes that may restore or exceed prior performance.
Muscle memories may be improved with practice
Muscle memories may be restored
Practice makes perfect
However, muscle memories like any other memory may become deficit, fade, become aberrant and in need of restoration.
Movement disorder therapies
Drugs – Drug treatment is the best-known therapy for suppression of movement disorders. However, in addition to disastrous side effects and possible drug dependency issues, they can cause movement disorders. Levodopa and dopamine agonists are known to cause proprioception deficits and drug induced dyskinesia.
Drug therapy is designed to “help” endogenous processes rather than challenge them. It is not unlike perpetually using a wheelchair to help support your body weight, the normal way of doing so gets weaker, atrophies, over time.
Use it or lose it
For more on drug therapy TREMOREX V DRUGS
Vestibular rehabilitation There are no drug therapies to mitigate balance disorders. All effective therapies center on training with exercises and devices that challenge the balance system, make balance more difficult, like standing on one foot, or on a balance board, boxing, Tai Chi, dancing, and physical therapy.
Such therapies are highly effective and clearly demonstrate that reflex muscle memories are plastic and can be trained, “use it or lose it” and “practice makes perfect” come to mind. Acrobats, athletes, dancers, demonstrate how balance can be improved well beyond normal, and people with balance disorders can restore normal balance.
Current therapies can be improved. Instead of responding to unpredictable random perturbations whilst assuming static postures on a small and unstable base of support, or executing physical activity, they can respond to high speed programmed perturbations whilst engaged in challenging posture, movement, and cognitive activity.
Do not wait for perturbations, create them
Compensatory measures – cause or effect of movement disorder symptoms
Reflex deficits adversely affect all movement and other systems including cognitive performance. Most Parkinsonian symptoms are automatic or conscious compensatory measures
For example, irregular posture and movement behavior is assumed to compensate for deficit balance and to avoid falling. People crouch or lean forward, outstretch hands, position feet, and avoid unnecessary movement to keep their center of gravity low and over a large base of support.
They deploy defensive movements by moving slowly, avoiding sharp turns, and avoiding walking backwards. They shuffle their feet while walking to always have both feet in contact with the floor. Freezing reduces risk of falling.
Other measures include behavioral changes like avoiding standing, walking, threading a needle, holding a glass of water, writing, speaking, or, using assistive devices like walkers, crutches, wearable devices, implants, drugs.
Voluntary movement is a poor substitute for reflexes
Perhaps the most devasting compensatory measure is to effectuate voluntary movement to assist or overcome defective involuntary movement. Movement is slow, staccato, deliberate, and carefully planned as muscle contractions are consciencely rather than automatically controlled. Voluntary movement uses sensory mechanisms like vision, feel, sound, rather than proprioception sensors.
When the brain becomes preoccupied micromanaging functions normally delegated, cognitive demands must wait. That is why people with movement disorders appear to not being able to walk and talk at the same time.
If the brain executes voluntary movement to supplement, replace or mitigate deficit automatic movement, other cognitive functions may be suspended
Compensatory measures v restoration
Compensatory measures, some of which have been described herein, seek to mitigate movement disorder symptoms. They are adaptations that can become new norms. The more effective the rehabilitation, the more permanent the new norm. Rehabilitation may be the only recourse for some people. However, other people may be capable of restoring deficit movement to normal or even superior levels. The latter is preferred and possible. Muscle memories including those designed to stabilize movement may be restored.
Restore rather than rehabilitate