Made by DATEXIS (Data Science and Text-based Information Systems) at Beuth University of Applied Sciences Berlin
Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
Funded by The Federal Ministry for Economic Affairs and Energy; Grant: 01MD19013D, Smart-MD Project, Digital Technologies
Pathologically, PMG is defined as “an abnormally thick cortex formed by the piling upon each other of many small gyri with a fused surface.” To view these microscopic characteristics, magnetic resonance imaging (MRI) is used. First physicians must distinguish between polymicrogyria and pachygyria. Pachygria leads to the development of broad and flat regions in the cortical area, whereas the effect of PMG is the formation of multiple small gyri. Underneath a computerized tomography (CT scan) scan, these both appear similar in that the cerebral cortex appears thickened. However, MRI with a T1 weighted inversion recovery will illustrate the gray-white junction that is characterized by patients with PMG. An MRI is also usually preferred over the CT scan because it has sub-millimeter resolution. The resolution displays the multiple folds within the cortical area, which is continuous with the neuropathology of an infected patient.
As previously noted, there are often few signs of white matter injury in newborns. Occasionally, physicians can make the initial observations of extreme stiffness or poor ability to suckle. The preliminary diagnosis of PVL is often made using imaging technologies. In most hospitals, premature infants are examined with ultrasound soon after birth to check for brain damage. Severe white matter injury can be seen with a head ultrasound; however, the low sensitivity of this technology allows for some white matter damage to be missed. Magnetic resonance imaging (MRI) is much more effective at identifying PVL, but it is unusual for preterm infants to receive an MRI unless they have had a particularly difficult course of development (including repeated or severe infection, or known hypoxic events during or immediately after birth). No agencies or regulatory bodies have established protocols or guidelines for screening of at-risk populations, so each hospital or doctor generally makes decisions regarding which patients should be screened with a more sensitive MRI instead of the basic head ultrasound.
PVL is overdiagnosed by neuroimaging studies and the other white matter lesions of the brain are underestimated. It is important to differentiate PVL from the following major white matter lesions in the cerebral hemispheres: edematous hemorrhagic leukoencephalopathy (OGL), telentsefalny gliosis (TG), diffuse leukomalacia (DFL), subcortical leukomalacia (SL), periventricular hemorrhagic infarction (PHI), intracerebral hemorrhage ( ICH), multicystic encephalomalacia (ME), subendymal pseudocyst. Diffuse white matter lesions of the cerebral hemispheres of the brain, accompanied by softening and spreading to the central and subcortical areas are more likely DFL, PHI and ME.
Preventing or delaying premature birth is considered the most important step in decreasing the risk of PVL. Common methods for preventing a premature birth include self-care techniques (dietary and lifestyle decisions), bed rest, and prescribed anti-contraction medications. Avoiding premature birth allows the fetus to develop further, strengthening the systems affected during the development of PVL.
An emphasis on prenatal health and regular medical examinations of the mother can also notably decrease the risk of PVL. Prompt diagnosis and treatment of maternal infection during gestation reduces the likelihood of large inflammatory responses. Additionally, treatment of infection with steroids (especially in the 24–34 weeks of gestation) have been indicated in decreasing the risk of PVL.
It has also been suggested that avoiding maternal cocaine usage and any maternal-fetal blood flow alterations can decrease the risk of PVL. Episodes of hypotension or decreased blood flow to the infant can cause white matter damage.
Gross examination exposes a pattern of many small gyri clumped together, which causes an irregularity in the brain surface. The cerebral cortex, which in normal patients is six cell layers thick, is also thinned. As mentioned prior, the MRI of an infected patient shows what appears to be a thickening of the cerebral cortex because of the tiny folds that aggregate causing a more dense appearance. However gross analysis shows an infected patient can have as few as one to all six of these layers missing.
Diagnosis requires a neurological examination. A neuroimaging exam can also be helpful for diagnosis. For example, an MRI can be used to discover the atrophy of the specific brain regions.
MMND can be differentially diagnosed from similar conditions like Fazio-Londe syndrome and amyotrophic lateral sclerosis, in that those two conditions don't involve sensorineural hearing loss, while MMND, Brown-Vialetto-Van Laere syndrome (BVVLS), Nathalie syndrome, and Boltshauser syndrome do. Nathalie syndrome does not involve lower cranial nerve symptoms, so it can be excluded if those are present. If there is evidence of lower motor neuron involvement, Boltshauser syndrome can be excluded. Finally, if there is a family history of the condition, then BVVLS is more likely, as MMND tends to be sporadic.
People with MMND become progressively more weak with time. Generally, affected individuals survive up to 30 years after they are diagnosed.
As athetosis is relatively difficult to treat, efforts are being made to help those with the condition live and perform tasks more effectively and more efficiently. One such example of work that has been recently undertaken is a project to help those affected with athetosis to use a computer with more ease. Software for the control of the computer uses joysticks that perform linear filtering to aid in control.
An additional possible treatment option for those afflicted with the symptom is neurostimulation. Studies have begun, and in cerebral palsy patients affected with dystonia-choreoathetosis, it has been demonstrated that neurostimulation has been an effective treatment in lessening symptoms in patients. There has not been a tremendous amount of experimentation, though, in this as a possible treatment option.
There are several different treatment approaches to dealing with athetosis. The most common methods are the use of drugs, surgical intervention, and retraining movements of the afflicted person. It is suggested that training a person to relearn movements can be helpful in select situations. Though, generally, this type of treatment will not work, in certain cases it can be found to be very helpful in treating the symptom of athetosis.
Drugs can also be used in the treatment of athetosis, however their collective effectiveness is not very convincing. There is not a single drug that is a standard among treatment. Many different medicines can be used, including:
- Artane
- Cogentin
- Curare, though not practical due to respiratory paralysis
- Tetrabenazine
- Haloperidol
- Thiopropazate
- Diazepam
Most instances of drug use where the symptoms seem to be lessened tend to be in more mild cases of athetosis.
Treatment by surgical intervention can obviously have the most immediate impact, again however, it is not a cure-all. In patients that have cerebral palsy as the cause of their athetosis, it has been demonstrated that a subthalamotomy tends to help relieve the extent of athetosis in approximately half of patients. Additionally, late 19th and early 20th century surgical accounts state that athetosis can be relieved by the removal of a part of the cerebral motor cortex or by cutting a part of the posterior spinal roots. Patients who undergo surgical treatment to relieve the athetosis often see significant improvement in the control of their limbs and digits. While surgery is often very beneficial in the short term and can produce near immediate results, in the long term it has been seen that its effects are not incredibly long lasting.
A working diagnosis is made from a neurological examination and evaluation. Parts of a complete examination include a physical examination, MRI, patient history, and electrophysiological and accelerometric studies. A diagnosis of solely intention tremor can only be made if the tremor is of low frequency (below 5 Hz) and without the presence of any resting tremors. Electrophysiological studies can be useful in determining frequency of the tremor, and accelerometric studies quantify tremor amplitude. MRI is used to locate damage to and degradation of the cerebellum that may be causing the intention tremor. Focal lesions such as neoplasms, tumors, hemorrhages, demyelination, or other damage may be causing dysfunction of the cerebellum and correspondingly the intention tremor.
Physical tests are an easy way to determine the severity of the intention tremor and impairment of physical activity. Common tests that are used to assess intention tremor are the finger-to-nose and heel-to-shin tests. In a finger-to-nose test, a physician has the individual touch their nose with their finger while monitoring for irregularity in timing and control of the movement. An individual with intention tremors will have coarse side-to-side movements that increase in severity as the finger approaches the nose. Similarly, the heel-to-shin test evaluates intention tremors of the lower extremities. In such a test, the individual, in a supine position, places one heel on top of the opposite knee and is then instructed to slide the heel down the shin to the ankle while being monitored for coarse and irregular side-to-side movement as the heel approaches the ankle.
Important historical elements to the diagnosis of intention tremor are:
1. age at onset
2. mode of onset (sudden or gradual)
3. anatomical affected sites
4. rate of progression
5. exacerbating and remitting factors
6. alcohol abuse
7. family history of tremor
8. current medications
Secondary symptoms commonly observed are dysarthria (a speech disorder characterized by poor articulation and slurred speech), nystagmus (rapid involuntary eye movement, especially rolling of the eyes), gait problems (abnormality in walking), and postural tremor or titubation (to-and-fro movements of the neck and trunk). A postural tremor may also accompany intention tremors.
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 muscle. This therapy can help strengthen these muscles to help maintain an upright posture. It has also been suggested that ankle-foot orthoses be prescribed for these patients. This would help patients with astasia maintain balance by preventing ankle dorsiflexion.
Currently, physical therapy and rehabilitation are widely accepted as the best treatments for the symptoms of astasia. There is, however, evidence to suggest that regulation of a patient's social situation and behavioral influences can influence the effectiveness of rehabilitation. A 1975 study shows that when a patient is given direct encouragement and social distractions their physical recovery proceeds much faster than when only basic instructions are provided to them.
The most common cause of diplegia in the legs is Cerebral Palsy. Paralysis of the legs may also be caused by trauma, injury, or genetics but this is very rare
Usually occurs within 2 periods:
1. With premature babies
2. full diagnosis usually between ages 2–5 years
Diplegia is usually not diagnosed before the age of 2 years yet the symptoms and signs of the earlier stages are typical and should enable the diagnosis to be made before the contractures have occurred. Parents suspecting diplegia should take their child to the doctor to potentially get an earlier diagnosis.
Socioeconomic correlates of health have been well established in the study of heart disease, lung cancer, and diabetes. Many of the explanations for the increased incidence of these conditions in people with lower socioeconomic status (SES) suggest they are the result of poor diet, low levels of exercise, dangerous jobs (exposure to toxins etc.) and increased levels of smoking and alcohol intake in socially deprived populations. Hesdorffer et al. found that low SES, indexed by poor education and lack of home ownership, was a risk factor for epilepsy in adults, but not in children in a population study. Low socioeconomic status may have a cumulative effect for the risk of developing epilepsy over a lifetime.
Diagnosis is suspected clinically and family history, neuroimaging and genetic study helps to confirm Behr Syndrome.
The eye findings of Parinaud's Syndrome generally improve slowly over months, especially with resolution of the causative factor; continued resolution after the first 3–6 months of onset is uncommon. However, rapid resolution after normalization of intracranial pressure following placement of a ventriculoperitoneal shunt has been reported.
Treatment is primarily directed towards etiology of the dorsal midbrain syndrome. A thorough workup, including neuroimaging is essential to rule out anatomic lesions or other causes of this syndrome. Visually significant upgaze palsy can be relieved with bilateral inferior rectus recessions. Retraction nystagmus and convergence movement are usually improved with this procedure as well.
Diffuse, symmetric white matter abnormalities were demonstrated by magnetic resonance imaging (MRI) suggesting that Behr syndrome may represent a disorder of white matter associated with an unknown biochemical abnormality.
There were also observations that hippocampal sclerosis was associated with vascular risk factors. Hippocampal sclerosis cases were more likely than Alzheimer's disease to have had a history of stroke (56% vs. 25%) or hypertension (56% vs. 40%), evidence of small vessel disease (25% vs. 6%), but less likely to have had diabetes mellitus (0% vs. 22%).
Posterior cerebral artery syndrome is a condition whereby the blood supply from the posterior cerebral artery (PCA) is restricted, leading to a reduction of the function of the portions of the brain supplied by that vessel: the occipital lobe, the inferomedial temporal lobe, a large portion of the thalamus, and the upper brainstem and midbrain.
This event restricts the flow of blood to the brain in a near-immediate fashion. The blood hammer is analogous to the water hammer in hydrology and it consists of a sudden increase of the upstream blood pressure in a blood vessel when the bloodstream is abruptly blocked by vessel obstruction. Complete understanding of the relationship between mechanical parameters in vascular occlusions is a critical issue, which can play an important role in the future diagnosis, understanding and treatment of vascular diseases.
Depending upon the location and severity of the occlusion, signs and symptoms may vary within the population affected with PCA syndrome. Blockages of the proximal portion of the vessel produce only minor deficits due to the collateral blood flow from the opposite hemisphere via the posterior communicating artery. In contrast, distal occlusions result in more serious complications. Visual deficits, such as agnosia, prosopagnosia or cortical blindness (with bilateral infarcts) may be a product of ischemic damage to occipital lobe. Occlusions of the branches of the PCA that supply the thalamus can result in central post-stroke pain and lesions to the subthalamic branches can produce “a wide variety of deficits”.
Left posterior cerebral artery syndrome presents alexia without agraphia; the lesion is in the splenium of the corpus callosum.
Many disorders of the basal ganglia are due to the dysfunction of a localized area. For this reason gene therapy seems viable for neurodegenerative disorders. Gene therapy is performed by replacing diseased phenotypes with new genetic material. This process is still in the early stages but early results are promising. An example of this therapy might involve implanting cells genetically modified to express tyrosine hydroxylase which, in the body, could be converted to dopamine. Increasing dopamine levels in the basal ganglia could possibly offset the effects of the Parkinson’s Disease.
""Astasia" redirects here. This term was also applied to chlorophyll-less "Euglena.
Astasis is a lack of motor coordination marked by an inability to stand, walk or even sit without assistance due to disruption of muscle coordination.
The term "astasia" is interchangeable with "astasis" and is most commonly referred to as "astasia" in the literature describing it. Astasis is the inability to stand or sit up without assistance in the absence of motor weakness or sensory loss (although the inclusion of 'the lack of motor weakness' has been debated by some physicians). It is categorized more as a symptom than an actual disease, as it describes a disruption of muscle coordination resulting in this deficit. The disturbance differs from cerebellar ataxia in that with astasis the gait can be relatively normal, with balance significantly impaired during transition from a seated to standing position. This balance impairment is similar to patients with vestibulocerebellar syndrome, which is a progressive neurological disease with many symptoms and effects.
Astasis has been seen in patients with diverse thalamic lesions, predominantly affecting the posterior lateral region of the brain. It is most frequently accompanied by abasia, although not always. Abasia is a symptom very similar to it and is the inability to walk. The two are most commonly seen in astasia-abasia, which is also called Blocq's disease. It is more common for astasia and abasia to be seen together than it is to see either one or the other.
Expensive and invasive, the above treatments are not guaranteed to work, and are not meeting the needs of patients. There is a need for a new, less expensive, less invasive form of treatment, two of which are postulated below.
- Spinal cord stimulation has been studied in the last couple of years. In a long case study, 8 patients were given spinal cord stimulation via insertion of a percutaneous lead at the appropriate level of the cervical or thoracic spine. Between 36 and 149 months after the stimulations, the patients were interviewed. 6 of the 8 had received initial pain relief, and three experienced long-term pain relief. Spinal cord stimulation is cheaper than brain stimulation and less invasive, and is thus a more promising option for pain treatment.
- In 2007, Dr. V. S. Ramachandran and his lab proposed that caloric stimulation might be effective in treating Dejerine–Roussy syndrome. They hypothesized that if cold water was streamed into the ear down the auditory canal, the symptoms associated with Dejerine–Roussy syndrome would be alleviated. Ramachandran stated that he had carried out provisional experiments on two patients and believed that their reactions supported his theory.
Akinetic mutism can be misdiagnosed as depression, delirium, or locked-in syndrome, all of which are common following a stroke. Patients with depression can experience apathy, slurring of speech, and body movements similar to akinetic mutism. Similarly to akinetic mutism, patients with locked-in syndrome experience paralysis and can only communicate with their eyes. Correct diagnosis is important to ensure proper treatment. A variety of treatments for akinetic mutism have been documented, but treatments vary between patients and cases.
Research has focused on finding a pharmacological treatment that is specific for intention tremor. Limited success has been seen in treating intention tremor with drugs effective at treating essential tremor. Clinical trials of levetiracetam, typically used to treat epilepsy, and pramipexole, used to treat resting tremor, were completed in 2009-2010 to establish their effectiveness in treating kinetic tremor. A clinical trial for riluzole, typically used to treat amyotrophic lateral sclerosis, was completed at the Sapienza University of Rome to evaluate its effectiveness of treating cerebellar ataxia and kinetic tremor.
Peripheral Territory Lesions
1. Contralateral homonymous hemianopsia
2. cortical blindness with bilateral involvement of the occipital lobe branches
3. visual agnosia
4. prosopagnosia
5. dyslexia, Anomic aphasia, color naming and discrimination problems
6. memory defect
7. topographic disorientation
Central Territory Lesions
1. central post-stroke (thalamic) pain: spontaneous pain, dysesthesias and sensory impairments
2. involuntary movements: chorea, intention tremor, hemiballismus
3. contralateral hemiplegia
4. Weber’s syndrome: occulomotor nerve palsy
5. Bálint's syndrome: loss of voluntary eye movements optic ataxia, asimultagnosia (inability to understand visual objects)
Lesionsing is the intentional destruction of neuronal cells in a particular area used for therapeutic purposes. Though this seems dangerous, vast improvements have been achieved in patients with movement disorders. The exact process generally involves unilateral lesioning in the sensorimotor territory of the GPi. This process is called pallidotomy. It is believed that the success of pallidotomies in reducing the effects of movement disorders may result from the interruption of abnormal neuronal activity in the GPi. This ablation technique can be viewed as simply removing a faulty piece of a circuit. With the damaged piece of the circuit removed, the healthy area of the circuit can continue normal function.