Astasis
Encyclopedia
"Astasia" redirects here. This term was also applied to chlorophyll
-less Euglena
.
Astasis (also known as astasia) is the inability to stand, walk or even sit up without assistance in the absence of motor weakness or sensory loss because of disruption of muscle coordination. The disturbance differs from cerebellar ataxia
in the fact that the gait
could be relatively normal, whereas standing up from a sitting position resembles a significant balance impairment in patients, like those with vestibulocerebellar syndrome
. It has been seen in patients with diverse thalamic lesions, predominantly affecting the posterior lateral region of the brain. It is most frequently, though not invariably accompanied by abasia
, an inability to walk, see Astasia-abasia, the most common disease astasis can be seen in.
Paul Oscar Blocq
(1860–1896) was the first to describe this phenomenon of the inability to maintain an upright posture despite normal function of the legs while sitting as astasis (or astasia). He recognized that paralysis, jumping, fits, tremors, and bizarre behavior could all be associated with the syndrome astasia-abasia. Jean-Martin Charcot, Charles Lasègue and other physicians prior to Blocq's description described astasis as “a special variety of motor feebleness of the legs from want of coordination in standing position and at gait.”
One study described a patient with astasis as "Lying in bed, his body posture was normal. When sitting, he tilted his body to the left. When asked to stand up, the patient rotated his trunk axis to the left (left shoulder going backwards), and tilted the body to the same side, making resistance to passive correction of posture in both planes. He was unable to stand, falling backwards or toward the left."
a lack of motor coordination marked by an inability to stand or sit without assistance.
The term astasis is interchangeable with astasia and in the literature about the phenomenon, it is most commonly referred to as astasia.
where patients had astasis (with abasia), and is credited with inventing the chair test for diagnoses. This test involves each patient first walking for 20-30 feet forward then 20-30 feet backward. The patients were then to sit in a swivel chair that had wheels and to push the chair forward and backward. In a follow-up study, these trials were compared with a control group of 9 patients with movement disorders with regard to the gait
that were non-psychogenic.
, which is the inability to walk due to lack of motor coordination. Astasis can be caused by a number of traumas or injuries to the motor cortexes of the brain.
One patient with astasis had a brain MRI, showing a hemorrhage in the right thalamo-mesencephalic junction. This region involves important structures for the control of postural stability, motor control, ocular movements and vestibulo-ocular integration. This region of the brain is not yet well understood and according to current knowledge, this is the first reported case with the simultaneous combination of astasis, Pretectal syndrome and asymmetrical asterixis
.
There are many speculations as to what is the main cause of astasis. A combination of weakness of the triceps surae muscle
, peripheral neuropathy
, and irregular postural movements are the leading theories thus far. Diabetes and spinal root or spinal cord lesions can also cause similar symptoms that are seen in patients with astasis. However, none of these have been proven definite. Many scientists also believe that this is a conversion disorder
, where patients exhibit symptoms without any neurological cause.
has been seen in many patients who have been diagnosed with astasis. This weakness can be caused by a myopathy
to that muscle group. The bilateral triceps surae muscle, made up of the gastrocnemius and the soleus, is essential to maintain a straight posture while standing. This indicates that weakness to this muscle is the cause of the swaying and impaired posture in patients with astasis. This weakness is seen regardless of whether somatosensory feedback from the legs is impaired, suggesting it is one of the main causes of astasia without abasia.
or the spinal root can cause damage to a nerve or nerve root in a person. Depending on where the abnormality is in a patient they can experience a wide range of symptoms, including those that are found in patients with astasis. It has been seen that patients with spinal atrophy who have astasia without abasia have neither sensory disturbances of the lower limbs or weakness in the hip extensor flexor muscles. This helps to indicate that one of the main causes of astasia without abasia is weakness in the triceps surae muscle.
Many other causes for astasia have been reported, such as temporal hypoperfusion in the left hemisphere and posterior cingulate infarction. However, there have only been one or two cases in which these causes have been reported.
. This therapy can help strengthen these muscles to help maintain an upright posture. Also it has been suggested that ankle-foot orthoses be prescribed for these patients. This would help patients with astasia help maintain balance by preventing ankle dorsiflexion
.
Chlorophyll
Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
-less Euglena
Euglena
Euglena is a genus of unicellular flagellate protists. It is the best known and most widely studied member of the phylum Euglenozoa , a diverse group containing some 44 genera and at least 800 species. Species of Euglena are found in fresh and salt waters...
.
Astasis (also known as astasia) is the inability to stand, walk or even sit up without assistance in the absence of motor weakness or sensory loss because of disruption of muscle coordination. The disturbance differs from cerebellar ataxia
Ataxia
Ataxia is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum...
in the fact that the gait
Gait
Gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency...
could be relatively normal, whereas standing up from a sitting position resembles a significant balance impairment in patients, like those with vestibulocerebellar syndrome
Vestibulocerebellar syndrome
Vestibulocerebellar syndrome, also known as vestibulocerebellar ataxia, is a progressive neurological disorder that causes a variety of medical problems. Initially symptoms present as periodic attacks of abnormal eye movements but may intensify to longer-lasting motor incapacity. The disorder has...
. It has been seen in patients with diverse thalamic lesions, predominantly affecting the posterior lateral region of the brain. It is most frequently, though not invariably accompanied by abasia
Abasia
Abasia is the inability to walk due to impaired muscle coordination. The term covers a spectrum of medical disorders such as:* choreic abasia: caused by chorea of the legs...
, an inability to walk, see Astasia-abasia, the most common disease astasis can be seen in.
Paul Oscar Blocq
Paul Oscar Blocq
Paul Oscar Blocq was a French pathologist who is remembered for his neuropathological work done with Jean-Martin Charcot and Gheorghe Marinescu at the Salpêtrière in Paris....
(1860–1896) was the first to describe this phenomenon of the inability to maintain an upright posture despite normal function of the legs while sitting as astasis (or astasia). He recognized that paralysis, jumping, fits, tremors, and bizarre behavior could all be associated with the syndrome astasia-abasia. Jean-Martin Charcot, Charles Lasègue and other physicians prior to Blocq's description described astasis as “a special variety of motor feebleness of the legs from want of coordination in standing position and at gait.”
One study described a patient with astasis as "Lying in bed, his body posture was normal. When sitting, he tilted his body to the left. When asked to stand up, the patient rotated his trunk axis to the left (left shoulder going backwards), and tilted the body to the same side, making resistance to passive correction of posture in both planes. He was unable to stand, falling backwards or toward the left."
Terminology
Astasia: (Etymology: Gk, a, stasis, not stand, a, basis, not step)a lack of motor coordination marked by an inability to stand or sit without assistance.
The term astasis is interchangeable with astasia and in the literature about the phenomenon, it is most commonly referred to as astasia.
Paul Oscar Blocq
Blocq's disease is a disorder named after Paul Oscar Blocq, which is also known as astasia-abasia, and is characterized by the inability to stand and walk, despite the capability to move ones' lower limbs when sitting down or lying down. He is credited with diagnosing the first cases (11 cases) in his work on Blocq's diseaseBlocq's disease
Blocq's disease is a neurological disorder or symptom named after Paul Oscar Blocq, a French physician, that may refer to*abasia*astasia-abasia *aboulia...
where patients had astasis (with abasia), and is credited with inventing the chair test for diagnoses. This test involves each patient first walking for 20-30 feet forward then 20-30 feet backward. The patients were then to sit in a swivel chair that had wheels and to push the chair forward and backward. In a follow-up study, these trials were compared with a control group of 9 patients with movement disorders with regard to the gait
Gait
Gait is the pattern of movement of the limbs of animals, including humans, during locomotion over a solid substrate. Most animals use a variety of gaits, selecting gait based on speed, terrain, the need to maneuver, and energetic efficiency...
that were non-psychogenic.
Signs and Symptoms
People who have astasis often experience odd gyrations, tight rope balancing, near falling, exaggerated effort, and atypical postures and weakness. Many other symptoms can include paralysis, jumping fits, and tremors.Causes
Astasis is very similar to abasiaAbasia
Abasia is the inability to walk due to impaired muscle coordination. The term covers a spectrum of medical disorders such as:* choreic abasia: caused by chorea of the legs...
, which is the inability to walk due to lack of motor coordination. Astasis can be caused by a number of traumas or injuries to the motor cortexes of the brain.
One patient with astasis had a brain MRI, showing a hemorrhage in the right thalamo-mesencephalic junction. This region involves important structures for the control of postural stability, motor control, ocular movements and vestibulo-ocular integration. This region of the brain is not yet well understood and according to current knowledge, this is the first reported case with the simultaneous combination of astasis, Pretectal syndrome and asymmetrical asterixis
Asterixis
Asterixis is a tremor of the wrist when the wrist is extended , sometimes said to resemble a bird flapping its wings. This motor disorder is characterized by jerking movements and is associated with various encephalopathies due especially to faulty metabolism...
.
There are many speculations as to what is the main cause of astasis. A combination of weakness of the triceps surae muscle
Triceps surae muscle
The triceps surae is a pair of muscles located at the calf - the gastrocnemius and the soleus...
, peripheral neuropathy
Peripheral neuropathy
Peripheral neuropathy is the term for damage to nerves of the peripheral nervous system, which may be caused either by diseases of or trauma to the nerve or the side-effects of systemic illness....
, and irregular postural movements are the leading theories thus far. Diabetes and spinal root or spinal cord lesions can also cause similar symptoms that are seen in patients with astasis. However, none of these have been proven definite. Many scientists also believe that this is a conversion disorder
Conversion disorder
Conversion disorder is a condition in which patients present with neurological symptoms such as numbness, blindness, paralysis, or fits without a neurological cause. It is thought that these problems arise in response to difficulties in the patient's life, and conversion is considered a psychiatric...
, where patients exhibit symptoms without any neurological cause.
Triceps Surae Muscle
Weakness of the triceps surae muscleTriceps surae muscle
The triceps surae is a pair of muscles located at the calf - the gastrocnemius and the soleus...
has been seen in many patients who have been diagnosed with astasis. This weakness can be caused by a myopathy
Myopathy
In medicine, a myopathy is a muscular disease in which the muscle fibers do not function for any one of many reasons, resulting in muscular weakness. "Myopathy" simply means muscle disease...
to that muscle group. The bilateral triceps surae muscle, made up of the gastrocnemius and the soleus, is essential to maintain a straight posture while standing. This indicates that weakness to this muscle is the cause of the swaying and impaired posture in patients with astasis. This weakness is seen regardless of whether somatosensory feedback from the legs is impaired, suggesting it is one of the main causes of astasia without abasia.
Peripheral neuropathy
Damage to the peripheral nerves coming from the legs to the somatosensory area is a leading theory to the cause of astasis. These damaged nerves prevent feedback for stabilization of posture for patients with astasis. This causes a disturbance in postural movements, such as a swaying around the legs and hip joints. This swaying may be seen only when a patient in standing still, and may disappear before walking, indicating that these patients exhibit astasia without abasia. This impairment of sensation is not always required for the sensation to develop. However, impairment often worsens astasia.Diabetes
Many patients who suffer from diabetes can have damage to a single nerve or groups of nerves in the body. Some patients experience damage to the nerves coming from the somatosensory area controlling postural stability, which can cause symptoms similar to those seen in patients with astasia. These patients exhibit trouble standing and hip swaying. This damage can be caused by a wide array of things, such as high blood glucose levels, or decreased blood flow to the brain.Spinal Cord/Root Lesions
Lesions in the spinal cordSpinal 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...
or the spinal root can cause damage to a nerve or nerve root in a person. Depending on where the abnormality is in a patient they can experience a wide range of symptoms, including those that are found in patients with astasis. It has been seen that patients with spinal atrophy who have astasia without abasia have neither sensory disturbances of the lower limbs or weakness in the hip extensor flexor muscles. This helps to indicate that one of the main causes of astasia without abasia is weakness in the triceps surae muscle.
Many other causes for astasia have been reported, such as temporal hypoperfusion in the left hemisphere and posterior cingulate infarction. However, there have only been one or two cases in which these causes have been reported.
Therapy
The most effective treatment of astasia seems to be a removal of stress inducing stimuli and allowing the patient to rest and regain strength. Despite the lack of a direct prescribable cure for the effect of astasia on the motor system of the legs, in almost all documented cases physical rehabilitation and relief from mental stressors have led to a full recovery. Although astasia is not expressly associated with any neurological disorders, there is a strong correlation between general mental hysteria and the symptoms of astasia. Therefore, isolation of the patient from the situation causing them hysteria is the most efficient way to rid them of disabling motor symptoms. Another method for treatment that patients who experience astasia is to have therapy for the triceps surae muscleTriceps surae muscle
The triceps surae is a pair of muscles located at the calf - the gastrocnemius and the soleus...
. This therapy can help strengthen these muscles to help maintain an upright posture. Also it has been suggested that ankle-foot orthoses be prescribed for these patients. This would help patients with astasia help maintain balance by preventing ankle dorsiflexion
Dorsiflexion
Dorsiflexion is the movement which decreases the angle between the dorsum of the foot and the leg, so that the toes are brought closer to the shin. The movement moving in opposite directions is called plantarflexion...
.