The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform

Mitchell Brigell - One of the best experts on this subject based on the ideXlab platform.

  • positive spontaneous visual phenomena limited to the hemianopic field in lesions of central visual pathways
    Neurology, 1996
    Co-Authors: Michael S Vaphiades, Gastone G Celesia, Mitchell Brigell
    Abstract:

    We prospectively studied 32 patients with ischemic infarction of the retrochiasmal visual pathways. Positive spontaneous visual phenomena (PSVP) in the blind hemifield were present in 13 patients (41%). The PSVP were subdivided into phosphenes, photopsias, visual hallucinations, Palinopsia, and agitated delirium with hemianopia. PSVP were never associated with auditory or other sensory positive phenomena, except in patients with agitated delirium. Patients with photopsias, phosphenes, Palinopsia, and visual hallucinations had similar lesions in MRI/CT, suggesting no anatomic area unique for these four phenomena. However, there was a significant difference in the severity of associated neurologic deficits between hemianopic patients with and without PSVP. Larger lesions destroying anteriorly located visual association areas precluded the development of PSVP, which may be related to release from inhibitory input of visual regions bordering the damaged area. Patients with the syndrome of agitated delirium and hemianopia had specific lesions involving the mesial aspect of the occipital lobe, the parahippocampal gyrus, and hippocampus.

Gastone G Celesia - One of the best experts on this subject based on the ideXlab platform.

  • chapter 18 positive spontaneous visual phenomena
    Handbook of Clinical Neurophysiology, 2005
    Co-Authors: Gastone G Celesia
    Abstract:

    Publisher Summary Positive spontaneous visual phenomena (PSVP) are defined as visual events occurring in isolation that is in the absence of altered consciousness, dementia, or psychosis. The Swiss naturalist Charles Bonnet in 1769 described PSVP as related to an impaired visual system. He reported vivid hallucinations of animals and people experienced by his grandfather who suffered from severe visual loss after bilateral cataract surgery. This chapter adopts the terminology of Vaphiades et al. , with the addition of visual distortions, such as micropsia and macropsia. The following PSVP are described in this chapter: phosphenes, photopsias, kinetopsia, Palinopsia, polyopia, visual allesthesia, visual distortions are abnormal perception of figures and objects, and can be further subdivided into: Macropsia, micropsia, pelopsia, teleopsia and metamorphopsia, visual hallucinations consist of complex scenes, which may include people, animals, furniture, landscapes, vehicles that may be stationary or mobile, colored or black and white, and which are perceived as real. Visual hallucinations are rarely static; they appear real or they look like a scene seen on a movie screen, and the Images move appropriately to the content of the scene.

  • positive spontaneous visual phenomena limited to the hemianopic field in lesions of central visual pathways
    Neurology, 1996
    Co-Authors: Michael S Vaphiades, Gastone G Celesia, Mitchell Brigell
    Abstract:

    We prospectively studied 32 patients with ischemic infarction of the retrochiasmal visual pathways. Positive spontaneous visual phenomena (PSVP) in the blind hemifield were present in 13 patients (41%). The PSVP were subdivided into phosphenes, photopsias, visual hallucinations, Palinopsia, and agitated delirium with hemianopia. PSVP were never associated with auditory or other sensory positive phenomena, except in patients with agitated delirium. Patients with photopsias, phosphenes, Palinopsia, and visual hallucinations had similar lesions in MRI/CT, suggesting no anatomic area unique for these four phenomena. However, there was a significant difference in the severity of associated neurologic deficits between hemianopic patients with and without PSVP. Larger lesions destroying anteriorly located visual association areas precluded the development of PSVP, which may be related to release from inhibitory input of visual regions bordering the damaged area. Patients with the syndrome of agitated delirium and hemianopia had specific lesions involving the mesial aspect of the occipital lobe, the parahippocampal gyrus, and hippocampus.

Andrew G. Lee - One of the best experts on this subject based on the ideXlab platform.

  • Palinopsia
    Spencer S. Eccles Health Sciences Library University of Utah, 2019
    Co-Authors: Andrew G. Lee, Department Of Ophthalmology, The Methodist Hospital, Professor Of Ophthalmology, Weill Cornell Medicine
    Abstract:

    Summary: Palinopsia is defined as seeing an image repeatedly, or having a persistent recurrence of an image, after the visual stimulus has been removed. From "palin-" meaning "repeat" and "-opsia" meaning "see". • Hallucinatory Palinopsia - seeing an image after the stimulus has been removed from the visual field • Illusory Palinopsia - seeing multiple interpretations/distortions of an image based on a stimulus in the visual field -Pathophysiology: higher-order, cortical-based phenomenon -Work-Up for Diagnosis: • MRI - lesion in occipital lobe or visual association cortex • Visual field exam - check for homonymous hemianopsia indicating structural lesions • EEG - consider for further work-up -Etiology: • Medication side effects. Most common is clomiphene, an infertility drug. • Substance use. Hallucinogens (ex. LSD), even if used in remote past. • Migraines • Seizures -Treatment: • Difficult to treat. • Remove offending agent, if identified. • Anti-migraine or anti-seizure medications. • Reassurance

  • Positive Visual Phenomenon II: Charles Bonnet, Visual Snow, Palinopsia
    Spencer S. Eccles Health Sciences Library University of Utah, 2019
    Co-Authors: Andrew G. Lee, Department Of Ophthalmology, The Methodist Hospital
    Abstract:

    Dr. Lee lectures medical students on positive visual phenomena (part II)

  • Palinopsia peeking behind doors of visual perception visual memory
    Ophthalmology Times, 2015
    Co-Authors: Andrew G. Lee
    Abstract:

    Palinopsia can be broadly defined as the persistence or recurrence of an image after the stimulus has been removed. Formed, high-resolution afterimages are typically more alarming to patients than unformed, blurred afterimages.

  • Palinopsia revamped a systematic review of the literature
    Survey of Ophthalmology, 2015
    Co-Authors: David Gersztenkorn, Andrew G. Lee
    Abstract:

    Palinopsia, the persistence or recurrence of visual images after the stimulus has been removed, is a nonspecific term that describes multiple types of visual symptoms with a wide variety of etiologies. For example, Palinopsia may be the presenting symptom of a potentially life-threatening posterior cortical lesion, yet it may also be a benign medication side effect. We comprehensively review all published cases and subdivide Palinopsia into two clinically relevant categories: illusory Palinopsia and hallucinatory Palinopsia.

Michael S Vaphiades - One of the best experts on this subject based on the ideXlab platform.

  • positive spontaneous visual phenomena limited to the hemianopic field in lesions of central visual pathways
    Neurology, 1996
    Co-Authors: Michael S Vaphiades, Gastone G Celesia, Mitchell Brigell
    Abstract:

    We prospectively studied 32 patients with ischemic infarction of the retrochiasmal visual pathways. Positive spontaneous visual phenomena (PSVP) in the blind hemifield were present in 13 patients (41%). The PSVP were subdivided into phosphenes, photopsias, visual hallucinations, Palinopsia, and agitated delirium with hemianopia. PSVP were never associated with auditory or other sensory positive phenomena, except in patients with agitated delirium. Patients with photopsias, phosphenes, Palinopsia, and visual hallucinations had similar lesions in MRI/CT, suggesting no anatomic area unique for these four phenomena. However, there was a significant difference in the severity of associated neurologic deficits between hemianopic patients with and without PSVP. Larger lesions destroying anteriorly located visual association areas precluded the development of PSVP, which may be related to release from inhibitory input of visual regions bordering the damaged area. Patients with the syndrome of agitated delirium and hemianopia had specific lesions involving the mesial aspect of the occipital lobe, the parahippocampal gyrus, and hippocampus.

Laurence A Bindoff - One of the best experts on this subject based on the ideXlab platform.

  • polg1 mutations cause a syndromic epilepsy with occipital lobe predilection
    Brain, 2008
    Co-Authors: Bernt A Engelsen, Charalampos Tzoulis, Bjorn Karlsen, Atle Lillebo, Liv Marie Laegreid, Jan Aasly, Massimo Zeviani, Laurence A Bindoff
    Abstract:

    The epileptic semiology of 19 patients (from 15 families) with mitochondrial disease due to mutations in the POLG1 gene is presented. The patients were either homozygous for the 1399G > A (p.A467T) or 2243G > C (p.W748S) mutations or compound heterozygotes for these two mutations. While the clinical features have been reviewed, detailed analysis of their epilepsy is presented for the first time. Irrespective of genotype, patients developed an epileptic syndrome with initial features of occipital lobe epilepsy. Occipital seizure phenomena included flickering coloured light, sometimes persisting for weeks, months or even years, ictal visual loss, horizontal/vertical nystagmus or oculoclonus, dysmorphopsia, micro-/macropsia and Palinopsia. Most patients developed simple partial seizure phenomena with motor symptoms suggesting frontal lobe seizure initiation or spread. Simple and complex partial seizures, clonic- and/or myoclonic seizures with epilepsia partialis continua and frequent convulsive status epilepticus were observed in this syndrome that appears to be a symptomatic and secondary generalized or multifocal epilepsy with focal occipital predilection. The mean age of seizure presentation was 18.4 years (6-58 years). All patients developed status epilepticus and 11 patient deaths were, all related to prolonged convulsive status epilepticus, including two with liver failure apparently precipitated by treatment with sodium valproate.