I have been thinking a lot about tone these days. Some people call it spasticity, but tone is the new terminology. Let’s see if it sticks over time. Tone or spasticity occurs when muscles contract without relaxation. It occurs typically not under your control, but the muscle is reacting anyway. Anyone can develop tone. It is often thought of as a consequence of spinal cord injury, but it can also occur with other neurological issues such as head injury, multiple sclerosis, cerebral palsy, stroke. It can appear temporarily in individuals without nerve injury in the form of a muscle cramp.
In spinal cord disease or injury, motor neurons are affected. Disruption in the cervical and thoracic levels result in an upper motor neuron injury (UMN). UMN injury occur above the anterior horn cell of the spinal cord nerves which results in the development of tone or spasticity. Interference in the lumbar and sacral spinal cord are usually lower motor neuron (LMN) injuries. LMN injures occur in the anterior horn or anterior gray column of the spinal cord which cause the muscles and reflexes to be flaccid or without tone. It is possible to have some symptoms of UMN and LMN injuries combined especially if the injury is in the lumbar area. The effects of spinal cord disease and injury can extend above and below the precise level of injury, further complicating the tone issue.
With spinal cord disease or injury, the body above the affected level works as it did before. So does the body below the level of injury. The issue is transmission of messages to get the body below the level of injury to react. From the brain, messages cannot reach the target of the activity that you want to do because of the interruption in the spinal cord. The area below the level of injury is also sending messages to the brain which get stopped at the level of injury. When this happens the chemical reaction of sending the message or signal to the brain cannot be transmitted so the chemical is released into the body which can be picked up by nearby nerves. The backlog of chemical release can cause muscle to overreact or tighten.
Tone can begin slowly and progress over time or it can develop quickly as soon as spinal shock resolves. If you have not experienced tone, you might first notice some sudden and involuntary tightening or jerking in your extremities. It may appear in just one muscle group, in one limb or several areas. Often people think there might be some functional return when they first experience this, only to be disappointed that it is tone. Individuals can get some single nerve return below the level of injury, so it is worth checking out any movements. Another sign that tone might be developing is when a stimulus is applied to a reflex, but the muscle does not relax as usual or your muscles may tighten for no apparent reason.
Reactions of the muscles to tone can be mild to severe. If you have sensation, tone can be quite painful. Moving a limb gently in the opposite direction as the tone can help release it. Tone can be a tight muscle contraction that passes or can be sustained. This is called a tonic spasm. A clonic spasm has a ‘beat’ to the muscle contraction. Application of mild pressure to both ends of the extremity to stretch the clonic spasm can help release it. For example, if a clonic spasm occurs in the calf, pressure to pushing the foot up and knee down will ‘break’ the rhythmic beat and tone.
It is easier to see tone in the muscles of your arms, legs, neck, or abdomen. However, tone can occur in any part of your body including the internal abdomen, chest and even in the muscles of the head for those with higher level injuries. Bowel and bladder muscles can develop tone as can any muscle in your body. You might notice sensations of indigestion which could actually be tone developing in your stomach muscles. Your bladder may spurt small amounts of urine or your bowel may expel stool due to tone. Diagnosis of tone can be more difficult to determine inside the trunk of the body because the symptoms of tone can mimic other medical issues.
In the limbs, muscles mostly come in pairs that balance each other. There are muscles for pushing away from the body and matched muscles for pulling toward the body. The muscles that pull toward the body are a bit stronger. If left untreated, spasticity can lead to chronic shortening of the affected muscles or contractures. Muscles with tone should be gently relaxed as being too aggressive can lead to torn muscles and broken bones.
Tone or spasticity in muscles can cause a limb to contract toward the core of the body. Thinking about the arms, the fingers curl toward the palm, wrists will contract to the inner arms, elbows to bend and shoulders to turn into the chest. The legs are a bit different as the hips flex causing the thigh to contract toward the stomach and the knees flex causing the shins to bend next to the thighs. With the legs up against the stomach, at the ankle the feet will extent toward the calves and the toes curl under. This brings the entire leg to the core of the body, looking much like the fetal position.
There are advantages to tone. Some people use their tone to create rigidity in the body for transfers or to grasp objects. Others use tone as a part of pressure release. If you have some tone, your extremities will move thereby releasing pressure points. This is not enough movement to totally release pressure, but it can help. You do need to be cautious that the tone is not creating a pressure injury through shearing of your skin on rough surfaces. Tone can also stimulate circulation as well as to keep muscles from shrinking from lack of use. Although these are benefits of tone, you need to assess the benefits to you. Some tone can be helpful, too much tone can lead to other complications such as contractures, pain, and stimulation of Autonomic Dysreflexia (AD).
Sudden development or an increase in tone can indicate something is happening in your body. Tone can increase with the development of a pressure injury, even before the red or purple spot appears. It can indicate a bladder or lung infection, or other problem in the abdomen such as bowel blockage, appendicitis, gall bladder attack, or other internal issues.
The frontline treatment for tone is movement. You can add movement to your routine with range of motion exercises. Our bodies all crave movement. Move your body or have it moved for you. Since your body still works below the level of injury but not under your control, you will need to manually supply movement to it. Movement can fatigue muscles which makes them less able to spasm. Movement also helps to keep muscles exercised and reduces your risk of developing secondary complications of spinal cord injury such as pressure injury, blood clots, bladder infections and improves bowel function. It can also help reduce development of other diseases such as insulin resistance and diabetes. Supplying movement or exercise to the entire body, including the area below the spinal cord injury is critical to your health.