neurotransmitter systems brain

Anton's syndrome

Anton’s Syndrome

            The Myriam-Webster dictionary defines Anton’s Syndrome (ABS) as an unusual disorder whereby blindness is linked with impairment to the cerebral cortex particularly of the occipital lobes is tied by the refutation of loss of vision by a patient also known as visual anosognosia. Essentially, it is a neurological visual disturbance that results from damage or abnormality in the brain instead of impairment due to abnormalities in the eye. ABS is a presentation of bilateral occipital lobe impairment in cortically blind individuals (Das & Naqvi, 2019). ABS patients are unaware of their condition and refute that they are blind. Typically, the patients deny the diagnosis and confabulate visions. ABS disorder is distinct from Charles Bonnet Syndrome, where patients who have experienced visual loss elaborate, and developed hallucinations with conservation understanding of their condition.

            According to Das & Naqvi (2019), the disorder was first named after Gabriel Anton, who described patients with total lack of individual insight of their blindness. Symptoms include: the affected individual may seem to have a standard vision because of the elaborate confabulations they have and description of their environment, usually resulting in late diagnosis of loss of vision. Impairment becomes evident when patients describe things or people that are absent or falling into objects; however, the patient progressively refutes blindness even with proven evidence. ABS is usually mainly secondary to cerebrovascular damage, hence mainly observed in elderly persons with several vascular risk elements. Besides, ABS has also been found in younger individuals when etiology is non-vascular.

            Gainotti (2019) states that the risk factors of ABS comprise of any activity that leads to occipital lobe blindness. The etiology of ABS includes head trauma, preeclampsia, multiple sclerosis, cardiac surgery, ischemic stroke, obstetric haemorrhage, angiitis and MELAS. The actual pathophysiology of ABS is unknown. The first explanation is that individuals with bilateral impairment to their main visual cortex also have impairment to their visual association cortex believed to because of their lack of insight on their condition. The other explanation is that it is subordinate to lesions of the parietal white matter resulting in a disconnection disorder. Moreover, as the link between the impaired visual cortex and functioning speech-language regions are damaged, it is likely that without input, the brain’s speech regions are accountable for confabulating replies.

            According to Das & Naqvi (2019), the diagnosis of ABS is conducted clinically depending on the history of idealistic confabulation or clinical evidence of blindness, diagnosis of occipital lobe impairment, and standard outcomes of the fundoscopic evaluation. Physical evaluation of ABS will present absolute vision loss. Fundoscopy will show unexceptional results. If patients are verbally instructed on which directions to observe, the ocular movements will be intact, but the patient will be unable to follow a light or finger. Potentially, cortically blind individuals can uphold the perception of the movements of arms, also known Riddoch Phenomenon. During eye examinations, ANS patients do not blink in reaction to the aggressive gesture of the hand. The pupillary reflexes will remain constant due to posterior location of occipital lesions to the lateral geniculate nucleus and not affecting the pupillary pathway. Nonetheless, individuals will remain NLP on acute evaluation although they will be totally oblivious of their vision loss. The comprehensive lack of awareness can be examined by talking to or watching the patient.

            MRI and head CT should be instructed to examine for ostensible impairment to the occipital lobe, probably for symptoms of haemorrhage or ischemia. Though, if secondary occurrence or exacerbation of another condition, for example, MS, demyelinating abrasions may be observed. Total blindness may be confirmed by proof of lack of stimulation of the evoked visual potentials (Das & Naqvi, 2019). ABS treatment depends on the treatment pf the perceived causative element of occipital lobe impairment to correct the causative agent.

            In conclusion, ABS is a neurological visual disturbance that results from damage or abnormality in the brain instead of impairment due to abnormalities in the eye. Affected individuals usually lack insight into their condition. ABS normally affects elderly persons; however, cases of ABS in young age groups have been reported. Treatment normally focuses on correcting the damage in the occipital lobe.

Reference

Das, J. M., & Naqvi, I. A. (2019). Anton Syndrome. In StatPearls [Internet]. StatPearls Publishing.

Gainotti, G. (2019). History of Anosognosia. In A History of Neuropsychology (Vol. 44, pp. 75-82). Karger Publishers.

Edited by  Paul Greenberg  on Jan 25 at 11:44am

One of the most common research techniques used for studying the brain is the magnetic resonance imaging scan that is known by most people as the MRI scan. The MRI scanning machine uses radio waves as well as strong magnetic fields to create images that are detailed of tissues and organs in the human body (Akkus et al., 2017). Based on the above statement, it is clear that MRI machines are not only used in the study of the brain but are also used in the study of other tissues and organs. It has often been claimed that medicine was revolutionized by the development of the MRI machine.

There is one main feature of the MRI scan machine that makes it compelling as a research technique. The method is a painless and non-invasive procedure. It does not require a patient of a study subject to having instruments put into them and neither does it expose the nakedness of a patient. The machine simply captures an image of the brain. The fact that the MRI scan is a non-invasive procedure makes it easy for researchers to convince study subjects or participants to consent to a brain study research (Sartori et al., 2018). The method as well provides an image of the brain that can help identify neuron activities. In addition, the imaging of MRI scans helps to identify anomalies of the brain. Furthermore, the preparation of a participant for an MRI scan is easy and inexpensive making it a preferred method for researchers interested in studying the brain.

The article that I chose focuses on the study of Parkinson’s disease using the MRI scan machine. Parkinson’s disease is a disorder that alters nerve cells deep in the brain. As illustrated in Heim et al., (2017), MRI scan machines help to capture images that show how the brain is affected by Parkinson’s disease. The images show the alteration of the brain as a result of the disease. The MRI method is a valuable method not only in the research of Parkinson’s disease but also in the study of other conditions that affect the brain.

References

Akkus, Z., Galimzianova, A., Hoogi, A., Rubin, D. L., & Erickson, B. J. (2017). Deep learning for brain MRI segmentation: state of the art and future directions. Journal of digital imaging, 30(4), 449-459.

Heim, B., Krismer, F., De Marzi, R., & Seppi, K. (2017). Magnetic resonance imaging for the diagnosis of Parkinson’s disease. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5514207/

Sartori, J. M., Reckziegel, R., Passos, I. C., Czepielewski, L. S., Fijtman, A., Sodré, L. A., ... & Kapczinski, F. (2018). Volumetric brain magnetic resonance imaging predicts functioning in bipolar disorder: A machine learning approach. Journal of psychiatric research, 103, 237-243.