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Handbook of Clinical Neurology 2021Perimetry is the quantitation of the visual field. This is done with a perimeter and usually involves measuring visual thresholds to a range of light stimuli. It is used... (Review)
Review
Perimetry is the quantitation of the visual field. This is done with a perimeter and usually involves measuring visual thresholds to a range of light stimuli. It is used clinically to map patterns of visual loss due to damage to the sensory visual system. This chapter discusses the types of perimetric testing and the psychophysics of perimetry. This is followed by the interpretation of perimetric results, the relevant visual system anatomy, and patterns of loss helpful for neurologic localization. Lastly, the difficult issue of deciding whether the visual field has changed is reviewed. Patterns of visual loss are the key to anatomic diagnosis. Strictly monocular defects map to the prechiasmal sensory visual system. Bitemporal hemianopia is the signature of damage to the optic chiasm. Incongruous homonymous hemianopia points to an optic tract lesion. The closer a lesion gets to the occipital cortex, the more congruous or similar are the patterns of homonymous hemianopia. Understanding these patterns, the basics of perimetry and other rules of localization will add an important dimension to the neurologist's localization arsenal.
Topics: Hemianopsia; Humans; Optic Chiasm; Vision Disorders; Visual Field Tests; Visual Fields
PubMed: 33832687
DOI: 10.1016/B978-0-12-821377-3.00003-9 -
Continuum (Minneapolis, Minn.) Oct 2019This article reviews the anatomy, symptoms, examination findings, and causes of diseases affecting the optic chiasm, optic tracts, optic radiations, and occipital lobes. (Review)
Review
PURPOSE OF REVIEW
This article reviews the anatomy, symptoms, examination findings, and causes of diseases affecting the optic chiasm, optic tracts, optic radiations, and occipital lobes.
RECENT FINDINGS
Modern ophthalmic imaging can be used to monitor the effects of diseases of the optic chiasm and tract on the retinal ganglion cells. It can also be used to visualize transsynaptic degeneration of the anterior visual pathway in the setting of acquired retrogeniculate lesions. Visual prostheses that directly stimulate the occipital lobe are a potential strategy for rehabilitation that is in active clinical trials.
SUMMARY
Detecting and characterizing visual deficits due to optic chiasm and retrochiasmal disease are important for the diagnosis, localization, and monitoring of neurologic disease; identifying patient disability; and guiding rehabilitation.
Topics: Adult; Brain Diseases; Female; Humans; Middle Aged; Occipital Lobe; Optic Chiasm; Optic Nerve Diseases; Vision Disorders; Visual Pathways
PubMed: 31584539
DOI: 10.1212/CON.0000000000000785 -
Medicina Clinica Mar 2021The treatment of non-functioning pituitary adenomas raises two questions: when should they be treated and what role does each available treatment play. We review the... (Review)
Review
The treatment of non-functioning pituitary adenomas raises two questions: when should they be treated and what role does each available treatment play. We review the usefulness of the different treatments and propose a therapeutic scheme based on the existing literature. Active treatment of pituitary adenomas should be performed when they produce symptoms, have contact with the optic tract, or have grown on imaging tests. The treatment is surgical, using radiotherapy for cases with significant non-removable postsurgical tumour remnants and for those in which histopathology studies show aggressive features. Medical treatment is reserved for situations in which surgical and radiotherapy treatments have been exhausted. The most advisable surgical treatment is endoscopic, although experienced neurosurgeons achieve results with microsurgery that are only slightly inferior.
Topics: Adenoma; Endoscopy; Humans; Microsurgery; Neurosurgical Procedures; Pituitary Neoplasms; Treatment Outcome
PubMed: 33454125
DOI: 10.1016/j.medcli.2020.08.019 -
Frontiers in Aging Neuroscience 2022To investigate the association between degeneration of retinal structure and shrinkage of the optic tract in patients after thalamic stroke.
OBJECTIVES
To investigate the association between degeneration of retinal structure and shrinkage of the optic tract in patients after thalamic stroke.
MATERIALS AND METHODS
Patients with unilateral thalamic stroke were included. Structural magnetic resonance imaging (MRI) and optical coherence tomography (OCT) were performed to obtain parameters of optic tract shrinkage (lateral index) and retina structural thickness (retinal nerve fiber layer, RNFL; peripapillary retinal nerve fiber layer, pRNFL; ganglion cell-inner plexiform layer, GCIP), respectively. Visual acuity (VA) examination under illumination was conducted using Snellen charts and then converted to the logarithm of the minimum angle of resolution (LogMAR). We investigated the association between LI and OCT parameters and their relationships with VA.
RESULTS
A total of 33 patients and 23 age-sex matched stroke-free healthy controls were enrolled. Patients with thalamic stroke showed altered LI compared with control participants ( = 0.011) and a significantly increased value of LI in the subgroup of disease duration more than 6 months ( = 0.004). In these patients, LI were significantly associated with pRNFL thickness (β = 0.349, 95% confidence interval [CI]: 0.134-0.564, = 0.002) after adjusting for confounders (age, sex, hypertension, diabetes, dyslipidemia, and lesion volume). LI and pRNFL were both significantly associated with VA in all patients (LI: β = -0.275, 95% CI: -0.539 to -0.011, = 0.041; pRNFL: β = -0.023, 95% CI: -0.046 to -0.001, = 0.040) and in subgroup of disease duration more than 6 months (LI: β = -0.290, 95% CI: -0.469 to -0.111, = 0.002; pRNFL: β = -0.041, 95% CI: -0.065 to -0.017, = 0.003).
CONCLUSION
Shrinkage of the optic tract can be detected in patients with thalamic stroke, especially after 6 months of stroke onset. In these patients, the extent of optic tract atrophy is associated with pRNFL thickness, and they are both related to visual acuity changes.
PubMed: 35966790
DOI: 10.3389/fnagi.2022.942438 -
Journal of Neuropathology and... Apr 2022Vision disorders are associated with traumatic brain injury (TBI) in 20%-40% of clinical cases and involve a diverse set of potential symptoms that can present acutely...
Vision disorders are associated with traumatic brain injury (TBI) in 20%-40% of clinical cases and involve a diverse set of potential symptoms that can present acutely or chronically. Due to its structure and position, the optic nerve is vulnerable to multiple forms of primary injury, which can result in traumatic optic neuropathy (TON). Multiple studies have shown that the optic tract may also be injured during TBI, though data regarding the temporospatial resolution of injury to the optic nerve are sparse. We evaluated the time course of optic nerve injury and visual impairments in our closed head impact acceleration mouse model of mild TBI (mTBI) designed to mimic repetitive injuries experienced in the context of sport. Our results show that inflammation and gliosis occur acutely in response to injury. Additionally, indications of optic nerve degeneration and functional loss of vision beginning at 1-month postinjury, and retinal ganglion cell loss at 7 months, revealed that the degeneration is continuous and permanent. Together, this study demonstrated that the optic nerve is vulnerable to damage during mTBI, which can cause TON and vision loss. These findings will be important for clinicians to consider to determine whether optic nerve is injured in the TBI patients with vision problems.
Topics: Animals; Brain Injuries; Brain Injuries, Traumatic; Humans; Mice; Mice, Inbred C57BL; Optic Nerve; Optic Nerve Injuries
PubMed: 35363316
DOI: 10.1093/jnen/nlac018 -
Developmental Neurobiology Aug 2019Pathologies of the optic nerve could result as primary insults in the visual tract or as secondary deficits due to inflammation, demyelination, or compressing effects of... (Review)
Review
Pathologies of the optic nerve could result as primary insults in the visual tract or as secondary deficits due to inflammation, demyelination, or compressing effects of the surrounding tissue. The extent of damage may vary from mild to severe, differently affecting patient vision, with the most severe forms leading to complete uni- or bilateral visual loss. The aim of researchers and clinicians in the field is to alleviate the symptoms of these, yet uncurable pathologies, taking advantage of known and novel potential therapeutic approaches, alone or in combinations, and applying them in a limited time window after the insult. In this review, we discuss the epidemiological and clinical profile as well as the pathophysiological mechanisms of two main categories of optic nerve pathologies, namely traumatic optic neuropathy and optic neuritis, focusing on the demyelinating form of the latter. Moreover, we report on the main rodent models mimicking these pathologies or some of their clinical aspects. The current treatment options will also be reviewed and novel approaches will be discussed.
Topics: Animals; Demyelinating Diseases; Disease Models, Animal; Humans; Optic Nerve; Optic Nerve Injuries; Optic Neuritis; Retinal Ganglion Cells
PubMed: 31297983
DOI: 10.1002/dneu.22710 -
Annual Review of Neuroscience Apr 2024Seeing in three dimensions is a major property of the visual system in mammals. The circuit underlying this property begins in the retina, from which retinal ganglion... (Review)
Review
Seeing in three dimensions is a major property of the visual system in mammals. The circuit underlying this property begins in the retina, from which retinal ganglion cells (RGCs) extend to the same or opposite side of the brain. RGC axons decussate to form the optic chiasm, then grow to targets in the thalamus and midbrain, where they synapse with neurons that project to the visual cortex. Here we review the cellular and molecular mechanisms of RGC axonal growth cone guidance across or away from the midline via receptors to cues in the midline environment. We present new views on the specification of ipsi- and contralateral RGC subpopulations and factors implementing their organization in the optic tract and termination in subregions of their targets. Lastly, we describe the functional and behavioral aspects of binocular vision, focusing on the mouse, and discuss recent discoveries on the evolution of the binocular circuit.
PubMed: 38635868
DOI: 10.1146/annurev-neuro-111020-093230 -
World Neurosurgery Mar 2021Lesioning the Forel field or the subthalamic region is considered a possible treatment for tremoric patients with Parkinson disease, essential tremor, and other...
BACKGROUND
Lesioning the Forel field or the subthalamic region is considered a possible treatment for tremoric patients with Parkinson disease, essential tremor, and other diseases. This surgical treatment was performed in the 1960s to 1970s and was an alternative to thalamotomy. Recently, there has been increasing interest in the reappraisal of stimulating and/or lesioning these targets, partly as a result of innovations in imaging and noninvasive ablative technologies, such as magnetic resonance-guided focused ultrasonography.
OBJECTIVE
We wanted to perform a thorough review of the subthalamic region, both from an anatomic and a surgical standpoint, to offer a comprehensive and updated analysis of the techniques and results reported for patients with tremor treated with different techniques.
METHODS
We performed a systematic review of the literature, gathering articles that included patients who underwent ablative or stimulation surgical techniques, targeting the pallidothalamic pathways (pallidothalamic tractotomy), cerebellothalamic pathway (cerebellothalamic tractotomy), or subthalamic area.
RESULTS
Pallidothalamic tractotomy consists of a reduced area that includes pallidofugal pathways. It may be considered an interesting target, given the benefit/risk ratio and the clinical effect, which, compared with pallidotomy, involves a lower risk of injury or involvement of vital structures such as the internal capsule or optic tract. Cerebellothalamic tractotomy and/or posterior subthalamic area are other alternative targets to thalamic stimulation or ablative surgery.
CONCLUSIONS
Based on the significant breakthrough that magnetic resonance-guided focused ultrasonography has meant in the neurosurgical world, some classic targets such as the pallidothalamic tract, Forel field, and posterior subthalamic area may be reconsidered as surgical alternatives for patients with movement disorders.
Topics: Cerebellum; Deep Brain Stimulation; Essential Tremor; Globus Pallidus; Humans; Implantable Neurostimulators; Neural Pathways; Parkinson Disease; Prosthesis Implantation; Radiofrequency Ablation; Subthalamus; Thalamus; Tremor; Ultrasonic Surgical Procedures
PubMed: 33276174
DOI: 10.1016/j.wneu.2020.11.143 -
Frontiers in Medicine 2022Optic tract lesions (OTL) are often difficult to diagnose. We suggest an algorithm to simplify the often-challenging diagnosis of OTL. Clinical and imaging data were...
Optic tract lesions (OTL) are often difficult to diagnose. We suggest an algorithm to simplify the often-challenging diagnosis of OTL. Clinical and imaging data were retrospectively collected from the electronic files of 6 patients diagnosed with OTL at a tertiary medical center in 2016-2020. The series included 4 children and 2 adults with an OTL caused by a glioma ( = 5) or motor vehicle accident ( = 1). Magnetic resonance imaging (MRI) revealed a suprasellar glioma involving the chiasm and tract alone (n = 1) and the ipsilateral optic nerve (n = 2) and only optic tract (3). Perimetry showed incongruent homonymous hemianopia in 3 patients. In two patients, perimetry could only be performed in one eye, and demonstrated hemianopia. In one patient perimetry was unreliable. Fundus examination revealed bow-tie atrophy in all patients. On optical coherence tomography (OCT) of the peripapillary retinal nerve fiber layer (RNFL) horizontal thinning was observed in the contralateral eye ( = 6). By presenting the information in a predefined order-visual field damage, OCT RNFL thickness, and MRI-the diagnosis could be easily reached even in children, and when other structures like the chiasm were involved. Fundus photographs easily detect bow tie atrophy in children. Systematic presentation of the data in a predefined order can ease the diagnostic process of OTLs.
PubMed: 36388882
DOI: 10.3389/fmed.2022.1029829 -
International Journal of Molecular... Feb 2023Wolfram syndrome 1 (WS1) is a rare autosomal recessive neurodegenerative disease caused by mutations in and genes that produce wolframin, a protein involved in... (Review)
Review
Wolfram syndrome 1 (WS1) is a rare autosomal recessive neurodegenerative disease caused by mutations in and genes that produce wolframin, a protein involved in endoplasmic reticulum calcium homeostasis and cellular apoptosis. Its main clinical features are diabetes insipidus (DI), early-onset non-autoimmune insulin-dependent diabetes mellitus (DM), gradual loss of vision due to optic atrophy (OA) and deafness (D), hence the acronym DIDMOAD. Several other features from different systems have been reported such as urinary tract, neurological, and psychiatric abnormalities. In addition, endocrine disorders that can appear during childhood and adolescence include primary gonadal atrophy and hypergonadotropic hypogonadism in males and menstrual cycle abnormalities in females. Further, anterior pituitary dysfunction with deficient GH and/or ACTH production have been described. Despite the lack of specific treatment for the disease and its poor life expectancy, early diagnosis and supportive care is important for timely identifying and adequately managing its progressive symptoms. The current narrative review focuses on the pathophysiology and the clinical features of the disease, with a special emphasis on its endocrine abnormalities that appear during childhood and adolescence. Further, therapeutic interventions that have been proven to be effective in the management of WS1 endocrine complications are discussed.
Topics: Male; Female; Adolescent; Humans; Child; Wolfram Syndrome; Neurodegenerative Diseases; Endocrinologists; Membrane Proteins; Mutation; Diabetes Mellitus, Type 2; Pediatricians
PubMed: 36835101
DOI: 10.3390/ijms24043690