Sensory Inventory XII

Proprioception (pronounced /ˌproʊpriːəˈsɛpʃən/ PRO-pree-o-SEP-shun); from Latin proprius, meaning "one's own" and perception) is the sense of the relative position of neighbouring parts of the body. Unlike the six exteroceptive senses (sight, taste, smell, touch, hearing, and balance) by which we perceive the outside world, and interoceptive senses, by which we perceive the pain and the stretching of internal organs, proprioception is a third distinct sensory modality that provides feedback solely on the status of the body internally. It is the sense that indicates whether the body is moving with required effort, as well as where the various parts of the body are located in relation to each other.

My inner sense of proprioception is somewhat compromised, because my inner ear sense of balance signal to the brain are poorly received, if at all. This give me some advantage in that I do no get dizzy -- but neither can I sense that I am bending over the same way most do it. I get visual cues from seeing the world around me, and can receive proprioception signals that tell me how my ankle and hip joints are situated with respect to the rest of my body. The rest is just some kind of magic. It works much better with all the senses firing together, let me assure you. I stumble a lot, because I do not effectively sense where my feet end up, or I forget inbetween steps. It is just another challenge I deal with.

Other sensory impairment continues as before, with some modifications. I can feel some touch on the bottoms of my feet now, but not much on the top. The left foot always sends pins-and-needles sensation like it is asleep. My hands are fully sensitive now most of the time, which is a great relief. My midsection and thighs continue to feel like sheathed in leather.

A slight diminishing in the degree of proprioception sensitivity in my hips has worried me. Sometimes it feels like before, when I could not stand up with my eyes shut. I talked to the neurologist about it last week, and he checked what he could, but it is a difficult issue to address objectively, and I may be stressing about not much. Anyway, it is something I will be paying close attention to over the next few months. Could be indicative of new Shwanomma -- new tumor development -- or regrowth of the tumor on my spinal column.

We'll see...

Physiology 101

In physiology, medicine, and anatomy, muscle tone (aka residual muscle tension or tonus) is the continuous and passive partial contraction of the muscles. It helps maintain posture, and it declines during REM sleep. It is not to be confused with the concept of toning in physical exercise.
Unconscious nerve impulses maintain the muscles in a partially contracted state. If a sudden pull or stretch occurs, the body responds by automatically increasing the muscle's tension, a reflex which helps guard against danger as well as helping to maintain balance.
The presence of near-continuous innervation makes it clear that tonus describes a "default" or "steady state" condition. There is, for the most part, no actual "rest state" insofar as activation is concerned.
In terms of skeletal muscle, both the extensor and flexor muscles, under normal enervation maintain a constant tone while "at rest" that maintains a normal posture.
Cardiac muscle and smooth muscle, although not directly connected to the skeleton, also have tonus in the sense that although their contractions are not matched with those of antagonist muscles; their non-contractive state is characterized by (sometimes random) enervation.

Physical disorders can result in abnormally low (hypotonia) or high (hypertonia) muscle tone. Another form of hypertonia is Paratonia, which is associated with dementia.

Paratonia or gegenhalten is classified as a form of hypertonia with an involuntary variable resistance (i.e reduced ability of a muscle to stretch) during passive movement (i.e a movement without effort). The disease develops during a period of dementia and the degree of effect is dependent upon the disease's progress. Paratonia was classified very recently by experts, and is unrelated to the much more typical spasticity associated with spastic diplegia and simlilar forms of cerebral palsy.
Clasp-knife response refers to a stretch reflex with a rapid decrease in resistance when attempting to flex a joint, usually during a neurological examination. It is one of the characteristic responses of a upper motor neuron lesion.
It gets its name from the resemblance between the motion of the limb and the sudden closing of a claspknife after sufficient pressure is applied.

Although seemingly a stretch reflex when flexing a joint, force from the muscle during the attempt to flex a joint is actually thought to be caused by the tendon reflex of the antagonistic muscle of that joint, which is an extensor muscle that becomes stretched. In upper motor neuron lesions, muscle tonus may increase and resistance of muscle to stretch increases. However, if sufficient force is applied, limb resistance suddenly decreases.

Walking notes

Just the simple act of standing up and walking has assumed a somewhat tentative, dubious nature for me. After the most recent stroke, I notice a deficit of natural balance, standing and walking.

Walking doesn't quite seem so spontaneous. I am noting that the beginning motion basically consists of falling, just slightly forward or back. This shifts the center of gravity, and starts a natural rhythm of alternating the feet in sequence to keep on balance.

Well, I am not performing this little dance quite as spontaneously as I would like it to be, these days. The biggest problem I encounter seems to result from a diminished sense of orientation. I cannot tell when my body is inclined to start falling forward, or back, until I actually start moving. It doesn't feel like anything. But I can see when things start to move. (With my eyes shut, I am helplessly lost, and I fall almost immediately, even trying to stay stationary.)

So, often my first step moves my feet, but my upper body is not leaning the right way in anticipation, and I start to fall. Most often, I tip over backwards.

I have usually been able to recover quickly. I guess I have had enough practice, by now. But it is with an uneasy lack of confidence that I navigate, now, carefully. And with excruciating slow pace.

My associates with the Forest Service were often impatient with me because they thought I hiked too slow. They ought to see me now!

Rehab progress 19

I have developed a condition the physicians refer to as "BPPV" for "benign paroxysmal positional vertigo". The dizzy drunk walking results in part due to misalignment of the rocks in my head. The doctors had to call it something a lot more sophisticated than just rocks in the head, so they refer to them as "otoconia". I knew it must be something like that.

Here is a link to some good information on this problem.

The treatment is simple and painless.

Poor balance and lack of control are some of my most serious problems right now, so hopefully this treatment will help correct it.