What is the Chaddock reflex?Under the Chaddock reflex, the neurologist understands a diseased foot joint reflex of the Babinski group.
The Chaddock reflex is a pathological reflex of the feet. He falls into the so-called Babinski group and is one of the pyramidal railway signs. All pyramidal signs are extraneous reflections. Other reflexes from the Babinski group are the Gordon and Babinski reflexes.
As a symptom, these pathological reflex movements are usually associated with a lesion of the central motor neurons. The motor neurons are part of the motor system and thus control the movements of the skeletal muscles. Both voluntary movements and reflexive movements are interconnected via the motor neurons. These neurons are part of the pyramidal tracts and thus of the central nervous system.
The lower motoneuron lies in the anterior horn of the spinal cord. From this, nerve impulses as bioelectrical excitations from the central nervous system are efferently transmitted to the muscles of the skeletal musculature.
The Chaddock reflex was named after Charles G. Chaddock, who documented reflex movement in the 20th century. The Japanese K. Yoshimura is regarded as the first describer of the Chaddock reflex, although it was Chaddock's extensive documentation that made the movement known as the reflex of the Babinski group.
Function & Task
Reflexes are automated and involuntary body movements, which are not connected in the central nervous system directly in the brain, but via the pyramidal tracts. This interconnection makes the movements more immediate and less time consuming. Only a few milliseconds pass between the trigger and the reflex on this trigger.
Reflex triggers are certain perceptions of the sensory systems. Most human reflexes are protective reflexes. Examples are the cough reflex and the eyelid reflex. For example, the lid closes involuntarily as soon as the visual system sees something approaching the eye. This protects the eyeball from injury and loss of function.
The cough reflex protects against suffocation. It is triggered when the receptors in the mucous membranes of the respiratory tract detect irritation. Such irritations are triggered by, for example, food components or fluids that inadvertently cross the trachea, not the esophagus. Its protective function adds an evolutionary value to human reflexes.
The reflex system of humans changes with age. For example, infants have significantly more reflexes than adults. In infants, the teat reflex is the best known reflex. For example, when a baby's finger is touched to his mouth, the touch automatically triggers a sucking motion. Thus, the child's mouth does not distinguish between the mother's breast and a handpiece or even an object such as the pacifier. The nipple reflex is usually reflected back to the first year of life of the infant, since the child from this age no longer relies on it.
The entire reflex system changes during the first years of life. These changes are mainly due to the development of superior motion control. The motor neurons are responsible for the overall control of voluntary and reflex motor skills.
Infants under one year have in addition to the nipple reflex all the reflexes of the Babinski group. The Chaddock reflex is also physiological for babies. Only in adults is there a morbid appearance. At the age of one year of age, the overall control of motor skills is not yet fully developed. Therefore, closely spaced muscle groups such as the phalanges always move as a group. Thus, in the Chaddock reflex triggered by the brushing of the outer foot back movement of the big toe up. The other phalanges lead at the same time a spreading movement.
When this phenomenon is observed on an adult human, there is, as it were, a regression to a stage during which the individual muscle groups were not yet individually activatable. Since the central motoneurons are the superordinate controlling body for movements, it can be assumed that these structures are damaged.
Diseases & complaints
The Chaddock reflex, like all other reflexes in the Babinski group, is a symptom. As a rule, the reflex movement is symptomatically associated with lesions of the central motor neurons.
The sensitivity of the Chaddock reflex, however, is controversial. Although the reflex examination is so far a standard examination in neurological diagnostics, the presence of a pathological reflex alone is not sufficient for the diagnosis of neurological diseases by far. For example, only several pyramidal tracts are an actual indication of motor neuron damage. In addition, the remaining findings must be characterized by abnormalities in the field of motor skills.
In the case of damage to the first motor neuron, the primary findings are usually spastic phenomena. Damage to the second motor neuron, on the other hand, manifests itself in muscle weakness, movement insecurity or paralysis. Both motor neurons can be damaged by various diseases of the central nervous system.
Among the best known of these diseases are multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). ALS is a degenerative disease of the motor nervous system. In contrast, multiple sclerosis is an autoimmune disease in which the affected person's immune system attacks the body's own nervous tissue and causes inflammation. Pyramidal tract signs such as the Chaddock reflex are used at the beginning of the disease as criteria for unfavorable prognosis.