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exaggerated deep tendon reflexes including spasticity, and clonus (a series of involuntary rapid muscle contractions) Such signs are collectively termed the "upper motor neuron syndrome". Affected muscles typically show multiple signs, with severity depending on the degree of damage and other factors that influence motor control. In ...
Clonus results due to an increased motor neuron excitation (decreased action potential threshold) and is common in muscles with long conduction delays, such as the long reflex tracts found in distal muscle groups. [7] Clonus is commonly seen in the ankle but may exist in other distal structures as well, such as the knee or spine. [8]
Spasticity, a velocity-dependent change in muscle tone; Clasp-knife response where initial higher resistance to movement is followed by a lesser resistance; Babinski sign is present, where the big toe is raised (extended) rather than curled downwards (flexed) upon appropriate stimulation of the sole of the foot. The presence of the Babinski ...
Hypertonia is a term sometimes used synonymously with spasticity and rigidity in the literature surrounding damage to the central nervous system, namely upper motor neuron lesions. [1] Impaired ability of damaged motor neurons to regulate descending pathways gives rise to disordered spinal reflexes , increased excitability of muscle spindles ...
Ankle clonus. Clonus is a set of involuntary and rhythmic muscular contractions and relaxations. Clonus is a sign of certain neurological conditions, particularly associated with upper motor neuron lesions involving descending motor pathways, and in many cases is accompanied by spasticity (another form of hyperexcitability). [1]
Spasticity can be in the form of the clasp-knife response, in which there is increased resistance only at the beginning or at the end of the movement. Rigidity can be of the leadpipe type, in which there is resistance throughout to passive movement, or it may be of cogwheel type, in which the resistance to passive movement is in a jerky manner.
Features other than weakness include decreased movement control, clonus (a series of involuntary rapid muscle contractions), spasticity, exaggerated deep tendon reflexes and decreased endurance. [citation needed] The incidence of hemiplegia is much higher in premature babies than term babies.
Stiff-person syndrome (SPS), also known as stiff-man syndrome, [1] is a rare neurological disorder of unclear cause characterized by progressive muscular rigidity and stiffness.