Spasticity
Encyclopedia
Spasticity is a feature of altered skeletal muscle
Skeletal muscle
Skeletal muscle is a form of striated muscle tissue existing under control of the somatic nervous system- i.e. it is voluntarily controlled. It is one of three major muscle types, the others being cardiac and smooth muscle...

 performance in muscle tone
Muscle tone
In physiology, medicine, and anatomy, muscle tone is the continuous and passive partial contraction of the muscles, or the muscle’s resistance to passive stretch during resting state. It helps maintain posture, and it declines during REM sleep.-Purpose:Unconscious nerve impulses maintain the...

 involving hypertonia
Hypertonia
Hypertonia a condition marked by an abnormal increase in muscle tension and a reduced ability of a muscle to stretch. It is caused by lesions to upper motor neurons in the central nervous system, which carry information from the central nervous system to the muscles and control posture, muscle...

, which is also referred to as an unusual "tightness" of muscles. Clinically spasticity is defined as velocity dependent resistance to stretch, where a lack of inhibition from the CNS results in excessive contraction of the muscles, ultimately leading to hyperflexia.

It mostly occurs in disorders of the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

 (CNS) impacting the upper motor neuron
Upper motor neuron
Upper motor neurons are motor neurons that originate in the motor region of the cerebral cortex or the brain stem and carry motor information down to the final common pathway, that is, any motor neurons that are not directly responsible for stimulating the target muscle...

 in the form of a lesion
Lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...

, such as spastic diplegia
Spastic diplegia
Spastic diplegia, historically known as Little's Disease, is a form of cerebral palsy that is a neuromuscular condition of hypertonia and spasticity in the muscles of the lower extremities of the human body, usually those of the legs, hips and pelvis...

, but it can also present in various types of multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

, which are autoimmune conditions.

Precise cause aside, whenever there is a loss of muscle tone inhibition from the brain to the spinal cord such that muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

s become overactive, this loss of inhibitory control can cause an ongoing level of contraction, with decreased ability for the affected individual to volitionally control the muscle contraction, and increased resistance felt on passive stretch.

The clinical underpinnings of two of the most common spasticity conditions, spastic diplegia
Spastic diplegia
Spastic diplegia, historically known as Little's Disease, is a form of cerebral palsy that is a neuromuscular condition of hypertonia and spasticity in the muscles of the lower extremities of the human body, usually those of the legs, hips and pelvis...

 and multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

, can be described as follows: in spastic diplegia
Spastic diplegia
Spastic diplegia, historically known as Little's Disease, is a form of cerebral palsy that is a neuromuscular condition of hypertonia and spasticity in the muscles of the lower extremities of the human body, usually those of the legs, hips and pelvis...

, the upper motor neuron lesion arises often as a result of neonatal asphyxia, while in conditions like multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

, spasticity comes as a result of the autoimmune destruction of the myelin sheaths around nerve endings — which in turn can mimic the gamma amino butyric acid deficiencies present in the damaged nerves of spastic diplegics, leading to roughly the same presentation of spasticity, but which clinically is fundamentally different from the latter.

Overall, a defining feature of spasticity is that the increased resistance to passive stretch is velocity-dependent. Lance (1980) describes it this way: “...a motor disorder, characterised by a velocity-dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks, resulting from hyper-excitability of the stretch reflex as one component of the upper motor neurone (UMN) syndrome”. Strangely, however, rather than being in the motor nerves as might be assumed to be the case, spasticity actually stems from the sensory nerves
Sensory nerves
Sensory nerves are nerves that receive sensory stimuli, such as how something feels and if it is painful, smooth, rough, etc.They are made up of nerve fibers, called sensory fibers .Sensory neurons are neurons that are activated by sensory input Sensory nerves are nerves that receive sensory...

.

Spasticity is found in conditions where the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 and/or spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...

 are damaged or fail to develop normally; these include cerebral palsy
Cerebral palsy
Cerebral palsy is an umbrella term encompassing a group of non-progressive, non-contagious motor conditions that cause physical disability in human development, chiefly in the various areas of body movement....

, multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

, spinal cord injury
Spinal cord injury
A spinal cord injury refers to any injury to the spinal cord that is caused by trauma instead of disease. Depending on where the spinal cord and nerve roots are damaged, the symptoms can vary widely, from pain to paralysis to incontinence...

 and acquired brain injury
Acquired brain injury
An acquired brain injury is brain damage caused by events after birth, rather than as part of a genetic or congenital disorder such as fetal alcohol syndrome, perinatal illness or perinatal hypoxia. ABI can result in cognitive, physical, emotional, or behavioural impairments that lead to permanent...

 including stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...

. Muscles affected in this way have many other potential features of altered performance in addition to spasticity, including muscle weakness; decreased movement control; clonus
Clonus
Clonus is a series of involuntary muscular contractions and relaxations. Clonus is a sign of certain neurological conditions, and is particularly associated with upper motor neuron lesions such as in stroke, multiple sclerosis, spinal cord damage and hepatic encephalopathy...

 (a series of involuntary rapid muscle contractions often symptomatic of muscle over-exertion and/or muscle fatigue); exaggerated deep tendon
Tendon
A tendon is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension. Tendons are similar to ligaments and fasciae as they are all made of collagen except that ligaments join one bone to another bone, and fasciae connect muscles to other...

 reflexes; and decreased endurance
Endurance
Endurance is the ability for a human or animal to exert itself and remain active for a long period of time, as well as its ability to resist, withstand, recover from, and have immunity to trauma, wounds, or fatigue. In humans, it is usually used in aerobic or anaerobic exercise...

.

Historical progression of spasticity hypotheses

The understanding of spasticity and the upper motor neuron lesion it is based on has progressed considerably in recent decades. However, the term "spasticity" is still often used interchangeably with "Upper Motor Neuron Syndrome" in the clinical settings, and it is not unusual to see patients labeled as spastic who demonstrate an array of upper motor neuron findings

Research has clearly shown that exercise is beneficial for spastic muscles, even though in the very early days of research it was assumed that strength exercise would increase spasticity. Also, from at least the 1950s through at least the 1980s, there was a strong focus on other interventions for spastic muscles, particularly stretching and splinting
Orthotics
Orthotics is a specialty within the medical field concerned with the design, manufacture and application of orthoses. An orthosis is an orthopedic device that supports or corrects the function of a limb or the torso...

, but the evidence does not support these as effective. In the case of spastic diplegia
Spastic diplegia
Spastic diplegia, historically known as Little's Disease, is a form of cerebral palsy that is a neuromuscular condition of hypertonia and spasticity in the muscles of the lower extremities of the human body, usually those of the legs, hips and pelvis...

 there is also a permanent neurosurgical treatment for spasticity, selective dorsal rhizotomy, that directly targets nerves in the spine that cause the spasticity, and destroys them, so that the spasticity can't be activated at all.

Presentation and assessment

Spasticity is assessed by feeling the resistance of the muscle to passive lengthening in its most relaxed state. A spastic muscle will have immediately noticeable, often quite forceful, increased resistance to passive stretch when moved with speed and/or while attempting to be stretched out, as compared to the non-spastic muscles in the same person's body (if any exist). As there are many features of the Upper Motor Neuron Syndrome, there are likely to be multiple other changes in affected musculature and surrounding bones, such as progressive misalignments of bone structure around the spastic muscles (leading for example to the scissor gait
Scissor gait
Scissor gait is a form of gait abnormality primarily associated with spastic cerebral palsy. It is associated with an upper motor neuron lesion.-Presentation:This gait pattern is reminiscent of a marionette...

 in spastic diplegia
Spastic diplegia
Spastic diplegia, historically known as Little's Disease, is a form of cerebral palsy that is a neuromuscular condition of hypertonia and spasticity in the muscles of the lower extremities of the human body, usually those of the legs, hips and pelvis...

. Also, following an upper motor neuron lesion, there may be multiple muscles affected, to varying degrees, depending on the location and severity of the upper motor neuron damage. The result for the affected individual, is that they may have any degree of impairment, ranging from a mild to a severe movement disorder. A relatively mild movement disorder may contribute to a loss of dexterity in an arm, or difficulty with high level mobility such as running or walking on stairs. A severe movement disorder may result in marked loss of function with minimal or no volitional muscle activation. There are several scales used to measure spasticity, such as the King’s Hypertonicity Scale , the Tardieu , and the Modified Ashworth . Of these three, only the King’s Hypertonicity Scale measures a range of muscle changes from the UMN lesion, including active muscle performance as well as passive response to stretch.

Assessment of a movement disorder featuring spasticity may involve several health professionals depending on the affected individual's situation, and the severity of their condition. This may include physical therapists, doctors (including neurologists and rehabilitation physicians)
American Academy of Physical Medicine and Rehabilitation
The American Academy of Physical Medicine and Rehabilitation is the national medical specialty society for physicians who specialize in physical medicine and rehabilitation . These physicians are called “physiatrists” or “rehabilitation physicians.” Founded in 1938, the mission of AAPM&R is to...

, orthotists and occupational therapists. Assessment is needed of the affected individual's goals, their function, and any symptoms that may be related to the movement disorder, such as pain. A thorough assessment will include analysis of posture, active movement, muscle strength, movement control and coordination, and endurance, as well as spasticity (response of the muscle to stretch). Spastic muscles typically demonstrate a loss of selective movement, including a loss of eccentric control (decreased ability to actively lengthen). While multiple muscles in a limb are usually affected in the Upper Motor Neuron Syndrome, there is usually an imbalance of activity, such that there is a stronger pull in one direction, such as into elbow flexion. Decreasing the degree of this imbalance is a common focus of muscle strengthening programs. Spastic movement disorders also typically feature a loss of stabilisation
Core stability
Core stability relates to the bodily region bounded by the abdominal wall, the pelvis, the lower back and the diaphragm and its ability to stabilise the body during movement. The main muscles involved include the transversus abdominus, the internal and external obliques, the quadratus lumborum and...

 of an affected limb or the head from the trunk
Torso
Trunk or torso is an anatomical term for the central part of the many animal bodies from which extend the neck and limbs. The trunk includes the thorax and abdomen.-Major organs:...

, so a thorough assessment requires this to be analysed as well.

Secondary effects are likely to impact on assessment of spastic muscles. If a muscle has impaired function following an upper motor neuron lesion, other changes such as increased muscle stiffness are likely to affect the feeling of resistance to passive stretch. Other secondary changes such as loss of muscle fibres following acquired muscle weakness are likely to compound the weakness arising from the upper motor neuron lesion. In severely affected spastic muscles, there may be marked secondary changes, such as muscle contracture
Contracture
A muscle contracture is a permanent shortening of a muscle or joint.. It is usually in response to prolonged hypertonic spasticity in a concentrated muscle area, such as is seen in the tightest muscles of people with conditions like spastic cerebral palsy....

, particularly if management has been delayed or absent.

Treatment

Treatment should be based on assessment by the relevant health professionals. For spastic muscles with mild-to-moderate impairment, exercise
Strength training
Strength training is the use of resistance to muscular contraction to build the strength, anaerobic endurance, and size of skeletal muscles. There are many different methods of strength training, the most common being the use of gravity or elastic/hydraulic forces to oppose muscle contraction...

 should be the mainstay of management, and is likely to need to be prescribed by a physical therapist or other health professional skilled in neurological rehabilitation.

Muscles with severe spasticity are likely to be more limited in their ability to exercise, and may require help to do this. They may require additional interventions, to manage the greater neurological impairment and also the greater secondary complications. These secondary complications involve the development of contractures, deformity and postural asymmetries. Interventions may include icing, serial casting, sustained stretching, inhibitory pressure and medical interventions. Treatment should be done with firm and constant manual contact positioned over nonspastic areas to avoid stimulating the spastic muscle(s). For muscles that lack any volitional control, such as after complete spinal cord injury
Spinal cord injury
A spinal cord injury refers to any injury to the spinal cord that is caused by trauma instead of disease. Depending on where the spinal cord and nerve roots are damaged, the symptoms can vary widely, from pain to paralysis to incontinence...

, exercise may be assisted, and may require equipment, such as using a standing frame to sustain a standing position.
A general treatment guideline can be followed that involves:
  • The initial focus on first activating contraction of antagonist muscles to provide reciprocal inhibition and lengthen spastic muscles
  • Reciprocal actions are attempted. Agonist contractions are performed first in small ranges progressing to larger arcs of movement
  • Highly stressful activities be minimized early in training
  • Functional skills are targeted for training
  • Patients and family/caregivers should be educated about the importance of maintaining range of motion and doing daily exercises


Medical interventions may include such medications as baclofen
Baclofen
Baclofen is a derivative of gamma-aminobutyric acid . It is primarily used to treat spasticity and is under investigation for the treatment of alcoholism....

, diazepam
Diazepam
Diazepam , first marketed as Valium by Hoffmann-La Roche is a benzodiazepine drug. Diazepam is also marketed in Australia as Antenex. It is commonly used for treating anxiety, insomnia, seizures including status epilepticus, muscle spasms , restless legs syndrome, alcohol withdrawal,...

, dantrolene
Dantrolene
Dantrolene sodium is a muscle relaxant that acts by abolishing excitation-contraction coupling in muscle cells, probably by action on the ryanodine receptor. It is the only specific and effective treatment for malignant hyperthermia, a rare, life-threatening disorder triggered by general anesthesia...

, or clonazepam
Clonazepam
Clonazepamis a benzodiazepine drug having anxiolytic, anticonvulsant, muscle relaxant, and hypnotic properties. It is marketed by Roche under the trade name Klonopin in the United States and Rivotril in Australia, Brazil, Canada and Europe...

. Phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

 injections can be used, or botulinum toxin
Botulinum toxin
Botulinum toxin is a protein produced by the bacterium Clostridium botulinum, and is considered the most powerful neurotoxin ever discovered. Botulinum toxin causes Botulism poisoning, a serious and life-threatening illness in humans and animals...

 injections into the muscle belly, to attempt to dampen the signals between nerve and muscle. The effectiveness of medications vary between individuals, and vary based on location of the upper motor neuron lesion (in the brain or the spinal cord). Medications are commonly used for spastic movement disorders, but research has not shown functional benefit for some drugs. Some studies have shown that medications have been effective in decreasing spasticity, but that this has not been accompanied by functional benefits. Surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

 could be required for a tendon release in the case of a severe muscle imbalance leading to contracture. In spastic CP, selective dorsal rhizotomy
Rhizotomy
A rhizotomy is a term chiefly referring to a neurosurgical procedure that selectively severs problematic nerve roots in the spinal cord, most often to relieve the symptoms of neuromuscular conditions such as spastic diplegia and other forms of spastic cerebral palsy...

 has also been used to decrease muscle overactivity.

Prognosis

The prognosis for those with spastic muscles depends on multiple factors, including the severity of the spasticity and the associated movement disorder, access to specialised and intensive management, and ability of the affected individual to maintain the management plan (particularly an exercise program). Most people with a significant UMN lesion will have ongoing impairment, but most of these will be able to make progress. The most important factor to indicate ability to progress is seeing improvement, but improvement in many spastic movement disorders may not be seen until the affected individual receives help from a specialised team or health professional.

See also

  • Stroke rehabilitation
    Stroke rehabilitation
    The primary goals of stroke management are to reduce brain injury and promote maximum patient recovery. Rapid detection and appropriate emergency medical care are essential for optimizing health outcomes. When available, patients are admitted to an acute stroke unit for treatment. These units...

  • Strength training
    Strength training
    Strength training is the use of resistance to muscular contraction to build the strength, anaerobic endurance, and size of skeletal muscles. There are many different methods of strength training, the most common being the use of gravity or elastic/hydraulic forces to oppose muscle contraction...

  • Cerebral palsy
    Cerebral palsy
    Cerebral palsy is an umbrella term encompassing a group of non-progressive, non-contagious motor conditions that cause physical disability in human development, chiefly in the various areas of body movement....

  • Spinal cord injury
    Spinal cord injury
    A spinal cord injury refers to any injury to the spinal cord that is caused by trauma instead of disease. Depending on where the spinal cord and nerve roots are damaged, the symptoms can vary widely, from pain to paralysis to incontinence...

  • Transverse myelitis
    Transverse myelitis
    Transverse myelitis is a neurological disorder caused by an inflammatory process of the spinal cord, and can cause axonal demyelination. The name is derived from Greek referring to the "spinal cord", and the suffix -itis, which denotes inflammation...

  • Gamma-aminobutyric acid
    Gamma-aminobutyric acid
    γ-Aminobutyric acid is the chief inhibitory neurotransmitter in the mammalian central nervous system. It plays a role in regulating neuronal excitability throughout the nervous system...

  • Rhizotomy
    Rhizotomy
    A rhizotomy is a term chiefly referring to a neurosurgical procedure that selectively severs problematic nerve roots in the spinal cord, most often to relieve the symptoms of neuromuscular conditions such as spastic diplegia and other forms of spastic cerebral palsy...

  • Phenol
    Phenol
    Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

  • Baclofen
    Baclofen
    Baclofen is a derivative of gamma-aminobutyric acid . It is primarily used to treat spasticity and is under investigation for the treatment of alcoholism....

  • Diazepam
    Diazepam
    Diazepam , first marketed as Valium by Hoffmann-La Roche is a benzodiazepine drug. Diazepam is also marketed in Australia as Antenex. It is commonly used for treating anxiety, insomnia, seizures including status epilepticus, muscle spasms , restless legs syndrome, alcohol withdrawal,...

  • Dantrolene
    Dantrolene
    Dantrolene sodium is a muscle relaxant that acts by abolishing excitation-contraction coupling in muscle cells, probably by action on the ryanodine receptor. It is the only specific and effective treatment for malignant hyperthermia, a rare, life-threatening disorder triggered by general anesthesia...

  • Tizanidine
    Tizanidine
    Tizanidine is a drug that is used as a muscle relaxant. It is a centrally acting α2 adrenergic agonist. It is used to treat the spasms, cramping, and tightness of muscles caused by medical problems such as multiple sclerosis, spastic diplegia, back pain, or certain other injuries to the spine or...

  • Pronator drift
    Pronator drift
    In medicine, pronator drift refers to a pathologic sign seen during a neurological examination. Jean Alexandre Barré is credited with having first described it thus it is sometimes known as the Barré test. A positive result indicates spasticity...

  • Brunnstrom Approach
    Brunnstrom Approach
    -History:The Brunnstrom Approach, developed by the Swedish physical therapist Signe Brunnstrom, emphasises the synergic pattern of movement which develops during recovery from hemiplegia...


External links

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