Spasticity
Spasticity (from Greek spasmos- 'drawing, pulling') is a feature of altered skeletal muscle performance with a combination of paralysis, increased tendon reflex activity, and hypertonia.
Clinically, spasticity results from the loss of inhibition of motor neurons, causing excessive velocity-dependent muscle contraction.
Spasticity is usually caused by damage to nerve pathways within the brain or spinal cord that control muscle movement.
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".
[6] Spasticity is found in conditions where the brain and/or spinal cord are damaged or fail to develop normally; these include cerebral palsy, multiple sclerosis, spinal cord injury and acquired brain injury including stroke.
Damage to the CNS as a result of stroke or spinal cord injury, alter the [net inhibition] of peripheral nerves in the affected region.
[citation needed] Clonus (i.e. involuntary, rhythmic, muscular contractions and relaxations) tends to co-exist with spasticity in many cases of stroke and spinal cord injury likely due to their common physiological origins.
[8] A commonly known feature of spasticity, known as Clasp-knife response is the sudden decrease of tone after initial resistance, also referred to as a lengthening reaction or a "catch-yield sequence".
Spasticity can be differentiated from rigidity with the help of simple clinical examination, as rigidity is a uniform increase in the tone of agonist and antagonist muscles which is not related to the velocity at which the movement is performed passively and remains the same throughout the range of movement while spasticity is a velocity-dependent increase in tone resulting from the hyperexcitability of stretch reflexes.
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.
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.
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.
Spastic movement disorders also typically feature a loss of stabilisation of an affected limb or the head from the trunk, so a thorough assessment requires this to be analysed as well.
For spastic muscles with mild-to-moderate impairment, exercise should be the mainstay of management, and is likely needed to be prescribed by a physiatrist (a doctor specialized in rehabilitation medicine), occupational therapist, physical therapist, accredited exercise physiologist (AEP) or other health professional skilled in neurological rehabilitation.
[18][19] Spasticity in cerebral palsy children is usually generalized although with varying degrees of severity across the affected extremities and trunk musculature.
[20][15] Treatment should be done with firm and constant manual contact positioned over nonspastic areas to avoid stimulating the spastic muscle(s).
Alternatively, rehabilitation robotics can be used to provide high volumes of passive or assisted movement, depending on the individual's requirements;[21] this form of therapy can be useful if therapists are at a premium, and has been found effective at reducing spasticity in patients with strokes.
[29][30] A 2004 study compared the effects of hydrotherapy on spasticity, oral baclofen dosage and Functional Independence Measure (FIM) scores of patients with a spinal cord injury (SCI).
It was found that subjects who received hydrotherapy treatment obtained increased FIM scores and a decreased intake of oral baclofen medication.
