Hypertonia

This article is about increased activity and resistance in muscles. For increased blood pressure, see Hypertension.

Hypertonia
Classification and external resources
ICD-10	P94.1
ICD-9	358, 779.89
DiseasesDB	20872
MeSH	D009122

Hypertonia is 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^[1] in the central nervous system, which carry information from the central nervous system to the muscles and control posture, muscle tone, and reflexes. When the injury occurs in children under the age of 2, the term cerebral palsy is often used.^[2] Damage to the central nervous system results in the loss of control of motor neurons and gives rise to disordered spinal reflexes, increased excitability of muscle spindles and decreased synaptic inhibition^[3]

Hypertonia may result from injury, disease, or conditions that involve damage to the central nervous system. Examples include spasticity, dystonia (prolonged muscle contractions that cause twisting and repetitive movements or abnormal posture) and rigidity.

Rigidity is a state of hypertonia where muscle resistance occurs throughout the entire range of motion and is independent of velocity (whereas spasticity is velocity-dependent). It is frequently associated with lesions of the basal ganglia. People with rigidity present with stiffness, decreased functional ability and flexibility. There are two main forms of rigidity: leadpipe and cogwheel. With leadpipe rigidity, resistance from the muscle(s) remains throughout the entire range of movement and it is not velocity-dependent.^[3] When rigidity is present with Parkinson's disease it is often termed as cogwheel. Cogwheel rigidity is a hypertonic state with rachetlike movements, and is believed to be present when rigidity and tremor occur together. Furthermore, the muscle(s) that have rigidity will not return to a fixed position after taken through range of motion^[4]

Spastic hypertonia involves uncontrollable muscle spasms, stiffening or straightening out of muscles, shock-like contractions of all or part of a group of muscles, and abnormal muscle tone. It is seen in disorders such as cerebral palsy, stroke, and spinal cord injury. A form of hypertonia unrelated to spasticity is known as Paratonia, which is associated with dementia.

Dystonic hypertonia refers to muscle resistance to passive stretching (in which a therapist gently stretches the inactive contracted muscle to a comfortable length at very low speeds of movement) and a tendency of a limb to return to a fixed involuntary (and sometimes abnormal) posture following movement. It is seen is the different forms of dystonia and sometimes in parkinsonism.

Rigidity is an involuntary stiffening or straightening out of muscles, accompanied by abnormally increased muscle tone and the reduced ability of a muscle to stretch. This type of hypertonia is most common in parkinsonism.

Hypertonia can be so severe that joint movement is not possible. Untreated hypertonia can lead to loss of function and deformity.^[2]

Management

Physiotherapy has been shown to be effective in controlling hypertonia with the use of static stretching which reduces motoneuron excitability.^[5] Other interventions include icing, inhibitory pressure (applying firm pressure over muscle tendon), promoting body heat retention, and rhythmic rotation (slow repeated rotation of affected body part to stimulate relaxation).^[6] A more unconventional method for limiting tone is to deploy quick repeated passive movements to an involved joint in cyclical fashion; this has also been demonstrated to show results on persons without physical disabilities.^[5] For a more permanent state of improvement, exercise and patient education is imperative.^[6] Isokinetic,^{[7][8][9][10]} aerobic,^[11][12][13] and strength training^{[14][15][16][17]} exercises should be performed as prescribed by a physiotherapist, and stressful situations that may cause increased tone should be minimized or avoided.^[6]

See also

• Dystonia
• Hypotonia
• Paratonia
• Spasticity
• Clasp-knife response

References

1. ^ Blumenfeld, Hal (2010). Neuroanatomy through Clinical Cases. Sunderland, MA: Sinauer Associates. pp. 241. ISBN 978-0-87893-058-6. 
2. ^ ^{a b} NINDS, Hypertonia Information Page.
3. ^ ^{a b} O'Sullivan, Susan (2007). Physical Rehabilitation. Philadelphia, PA: F.A Davis Company. pp. 234. 
4. ^ Glupta, Alok. "Rigidity". http://www.parkinsonindia.org/rigidity.htm. Retrieved 12 May 2011. 
5. ^ ^{a b} Chang, Y. -J.; Fang, C. -Y.; Hsu, M. -J.; Lien, H. -Y.; Wong, M. -K. (2007). "Decrease of hypertonia after continuous passive motion treatment in individuals with spinal cord injury". Clinical Rehabilitation 21 (8): 712–718. doi:10.1177/0269215507079137. PMID 17846071.  edit
6. ^ ^{a b c} O'Sullivan, Susan (2007). Physical Rehabilitation. Philadelphia, PA: F.A Davis Company. p 497.
7. ^ Giuliani, C: The relationship of spasticity to movement and consideration for therapeutic interventions. Neurol Report (now JNPT) 21:78, 1997.
8. ^ Light, K, and Giuliane, C: Effect of isokinetic exercise effort on arm coordination of spastic hemiparetic subjects. Neurology Report (now JNPT) 16:19, 1992.
9. ^ Giuliani, C, Light, K, and Rose, D: The effects of isokinetic exercise program in gait patterns of patients with hemiparesis. Neurology Report (now JNPT) 4:23, 1993.
10. ^ Brown, D, and Kautz, S: Increased workload enhances force output during pedaling exercise in persons with post stroke hemiplegia. Stroke 29:598, 1998.
11. ^ Hunter, M, Tomberlin, J, and Kuna, S: Progressive exercise testing in closed head-injuried subjects comparison of exercise apparatus in assessment of a physical conditioning program. Phys Ther 70:363, 1990.
12. ^ Jankowski, LW, and Sullivan, SJ: Aerobic and neuromuscular training: Effect on the capacity efficiency and fatigability of patients with traumatic brain injuries. Arch Phys Med Rehab 71 (7): 500, 1990
13. ^ Potempa, K, et al: Physiologic outcomes of aerobic exercise training in hemiparetic stroke patients. Stroke 26:101, 1995.
14. ^ Damiano, D, and Abel, M: Functional outcomes of strength training in spastic cerebral palsy. Arch Phys Med Rehabil 79:119, 1998. Damiano, D.; Abel, M. F. (1998). "Functional outcomes of strength training in spastic cerebral palsy*1, *2". Archives of Physical Medicine and Rehabilitation 79 (2): 119–125. doi:10.1016/S0003-9993(98)90287-8. PMID 9473991.  edit
15. ^ Damiano, D, Vaughan, C, and Abel, M: Muscle response to heavy resistance exercise in children with spastic cerebral palsy. Dev Med Child Neurol 38:731, 1995 Damiano, D. L.; Vaughan, C. L.; Abel, M. E. (2008). "Muscle Response to Heavy Resistance Exercise in Children with Spastic Cerebral Palsy". Developmental Medicine & Child Neurology 37 (8): 731–739. doi:10.1111/j.1469-8749.1995.tb15019.x.  edit
16. ^ Miller, G, Light, K, and Kellog, R: Comparison of isometric force control measures in spastic muscle of post-stroke individuals before and after graded resistive exercise. Neurol Report 20:92, 1996
17. ^ Hall, C, and Light, K: Heavy restrictive exercise effect on reciprocal movement coordination of closed-head injured subjects with spasticity. Neurology Report (now JNPT) 14:19, 1990.

External links

• "The Clasp Knife Phenomenon" at mcg.edu