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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)
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Individuals with quadrantanopia often modify their behavior to compensate for the disorder, such as tilting of the head to bring the affected visual field into view. Drivers with quadrantanopia, who were rated as safe to drive, drive slower, utilize more shoulder movements and, generally, corner and accelerate less drastically than typical individuals or individuals with quadrantanopia who were rated as unsafe to drive. The amount of compensatory movements and the frequency with which they are employed is believed to be dependent on the cognitive demands of the task; when the task is so difficult that the subject's spatial memory is no longer sufficient to keep track of everything, patients are more likely to employ compensatory behavior of biasing their gaze to the afflicted side. Teaching individuals with quadrantanopia compensatory behaviors could potentially be used to help train patients to re-learn to drive safely.
Quadrantanopia, quadrantanopsia, or quadrant anopia refers to an anopia affecting a quarter of the field of vision.
It can be associated with a lesion of an optic radiation. While quadrantanopia can be caused by lesions in the temporal and parietal lobes, it is most commonly associated with lesions in the occipital lobe.
An anopsia or anopia is a defect in the visual field. If the defect is only partial, then the portion of the field with the defect can be used to isolate the underlying cause.
Types of partial anopsia:
- Hemianopsia
- Homonymous hemianopsia
- Heteronymous hemianopsia
- Binasal hemianopsia
- Bitemporal hemianopsia
- Superior hemianopia
- Inferior hemianopia
- Quadrantanopia
The term "anopsia" comes from the Ancient Greek ἀν- ("an-"), "un-" and ὄψις ("opsis") "sight".
Hemianopsia, or hemianopia, is a decreased vision or blindness (anopsia) in half the visual field, usually on one side of the vertical midline. The most common causes of this damage are stroke, brain tumor, and trauma.
This article deals only with permanent hemianopsia, and not with transitory or temporary hemianopsia, as identified by William Wollaston PRS in 1824. Temporary hemianopsia can occur in the aura phase of migraine.
When the pathology involves both eyes, it is either homonymous or Heteronymous.
Phonological dyslexia is a reading disability that is a form of alexia (acquired dyslexia), resulting from brain injury, stroke, or progressive illness and that affects previously acquired reading abilities. The major distinguishing symptom of acquired phonological dyslexia is that a selective impairment of the ability to read pronounceable non-words occurs although the ability to read familiar words is not affected. It has also been found that the ability to read non-words can be improved if the non-words belong to a family of pseudohomophones.
There are a few scans and tests that the physician can conduct in order to diagnose a person with craniopharyngioma. Your doctor may order a high-resolution magnetic resonance imaging (MRI) scan. This test is valuable because it allows the neuroradiologist to view the tumor from different angles.
In some cases, a powerful 3T (Tesla) MRI scanner can help define the location of critical brain structures affected by the tumor.The histologic pattern consists of nesting of squamous epithelium bordered by radially arranged cells. It is frequently accompanied by calcium deposition and may have a microscopic papillary architecture.A computed tomography (CT) scan is also a good diagnostic tool as it detects calcification in the tumor.
Two distinct types are recognized:
- Adamantinomatous craniopharyngiomas, which resemble ameloblastomas (the most common type of odontogenic tumor), are characterized by activating CTNNB1 mutations; and,
- Papillary craniopharyngiomas are characterized by BRAFv600E mutations.
In the adamantinomatous type, calcifications are visible on neuroimaging and are helpful in diagnosis.
The papillary type rarely calcifies. A vast majority of craniopharyngiomas in children are adamantiomatous whereas both subtypes are common in adults. Mixed type tumors also occur.
On macroscopic examination, craniopharyngiomas are cystic or partially cystic with solid areas. On light microscopy, the cysts are seen to be lined by stratified squamous epithelium. Keratin pearls may also be seen. The cysts are usually filled with a yellow, viscous fluid which is rich in cholesterol crystals. Of a long list of possible symptoms, the most common presentations include: headaches, growth failure, and bitemporal hemianopsia.
Craniopharyngiomas are usually successfully managed with a combination of adjuvant chemotherapy and neurosurgery. Recent research describes the rare occurrence of malignant transformations of these normally benign tumors. Malignant craniopharyngiomas can occur at any age, are slightly more common in females, and are usually of the adamantinomatous type.
The malignant transformations can take years to occur (although 1 in 5 of the diagnosed cases were de novo transformations), hence the need for lengthier follow up in patients diagnosed with the more common benign forms.
There was no link found between malignancy and initial chemo-radiotherapy treatment, and the overall survival rate was very poor with median survival being 6 months post diagnosis of malignancy.
An investigation conducted by Harley, T. A., and O'Mara, D.A. (2006) found that hyphenation significantly improved a participant`s reading ability. The subject suffered from phonological dyslexia that was due to a deficiency in graphemic parsing. The study suggested that hyphenation might be generally useful as a strategy to assist phonological dyslexics.
Pituitary incidentalomas are pituitary tumors that are characterized as an incidental finding. They are often discovered by computed tomography (CT) or magnetic resonance imaging (MRI), performed in the evaluation of unrelated medical conditions such as suspected head trauma, in cancer staging or in the evaluation of nonspecific symptoms such as dizziness and headache. It is not uncommon for them to be discovered at autopsy. In a meta-analysis, adenomas were found in an average of 16.7% in postmortem studies, with most being microadenomas (<10mm); macrodenomas accounted for only 0.16% to 0.2% of the decedents. While non-secreting, noninvasive pituitary microadenomas are generally considered to be literally as well as clinically benign, there are to date scant studies of low quality to support this assertion.
It has been recommended in the current Clinical Practice Guidelines (2011) by the Endocrine Society - a professional, international medical organization in the field of endocrinology and metabolism - that all patients with pituitary incidentalomas undergo a complete medical history and physical examination, laboratory evaluations to screen for hormone hypersecretion and for hypopituitarism. If the lesion is in close proximity to the optic nerves or optic chiasm, a visual field examination should be performed. For those with incidentalomas which do not require surgical removal, follow up clinical assessments and neuroimaging should be performed as well follow-up visual field examinations for incidentalomas that abut or compress the optic nerve and chiasm and follow-up endocrine testing for macroincidentalomas.
Carcinomas that metastasize into the pituitary gland are uncommon and typically seen in the elderly, with lung and breast cancers being the most prevalent, In breast cancer patients, metastases to the pituitary gland occur in approximately 6-8% of cases.
Symptomatic pituitary metastases account for only 7% of reported cases. In those who are symptomatic Diabetes insipidus often occurs with rates approximately 29-71%. Other commonly reported symptoms include anterior pituitary dysfunction, visual field defects, headache/pain, and ophthalmoplegia.