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Oculomotor abnormalities are fast becoming a proxy for disease diagnosis and progression. Saccades-ballistic eye movements-are known to be affected by dopaminergic cell loss in the basal ganglia, caused by Parkinson's disease. Pharmaceutical and neurosurgical interventions such as deep brain stimulation and functional neurosurgery have both been noted to have an effect on saccades. Comparing and contrasting these effects may yield insights into Parkinson's disease pathophysiology, and the mechanisms of pharmacological and neurosurgical treatments. Computational models of saccadic control, such as the LATER model, can help to interpret the distribution of saccadic latencies, providing a framework for objectively comparing the effects of pharmaceutical interventions and deep brain stimulation., (© 2019 Elsevier B.V. All rights reserved.)

We describe a patient presenting with vertical one-and-a-half syndrome and concomitant contralesional horizontal gaze paresis as the result of a solitary neurocysticercosis (NCC) lesion in the right midbrain extending into the thalamomesencephalic junction. The patient received an albendazole-dexamethasone course which resulted in resolution of his symptoms. The neuro-ophthalmological complications of NCC are reviewed and the clinical topography of the neuro-ophthalmological findings of this unusual observation are discussed., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Paroxysmal reversal of spontaneous nystagmus has rarely been described. Herein, we report recurrent bouts of vertigo and oscillopsia in association with reversed spontaneous nystagmus in a patient with prior surgical resection of the cerebellar vermis due to medulloblastoma and subsequent labyrinthine damage. The symptoms almost completely resolved with carbamazepine. The episodes may be ascribed to paroxysmal reversal of the vestibular asymmetry due to intermittent decompensation by the deficient cerebellum., (Copyright © 2012 Elsevier B.V. All rights reserved.)

In this report, we present two unusual ocular manifestations due to CNS tuberculosis. One of the cases is a 7 years' old boy with brain stem tuberculoma who presented with horizontal gaze palsy. The other is a 14 years' old girl with temporal lobe tuberculoma who presented with unilateral sixth nerve paresis and papilledema. Both responded well to treatment with antitubercular drugs. It highlights the importance of gaze palsy as a rare manifestation of CNS tuberculosis.

Background: Smooth pursuit deficits are an intermediate phenotype for schizophrenia that may result from disturbances in visual motion perception, sensorimotor transformation, predictive mechanisms, or alterations in basic oculomotor control. Which of these components are the primary causes of smooth pursuit impairments and whether they are impaired similarly across psychotic disorders remain to be established., Methods: First-episode psychotic patients with bipolar disorder (n = 34), unipolar depression (n = 24), or schizophrenia (n = 77) and matched healthy participants (n = 130) performed three smooth pursuit tasks designed to evaluate different components of pursuit tracking., Results: On ramp tasks, maintenance pursuit velocity was reduced in all three patients groups with psychotic bipolar patients exhibiting the most severe impairments. Open loop pursuit velocity was reduced in psychotic bipolar and schizophrenia patients. Motion perception during pursuit initiation, as indicated by the accuracy of saccades to moving targets, was not impaired in any patient group. Analyses in 138 participants followed for 6 weeks, during which patients were treated and psychotic symptom severity decreased, and no significant change in performance in any group was revealed., Conclusions: Sensorimotor transformation deficits in all patient groups suggest a common alteration in frontostriatal networks that dynamically regulate gain control of pursuit responses using sensory input and feedback about performance. Predictive mechanisms appear to be sufficiently intact to compensate for this deficit across psychotic disorders. The absence of significant changes after acute treatment and symptom reduction suggests that these deficits appear to be stable over time., (Copyright 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.)

Opsoclonus-myoclonus-ataxia syndrome (OMS) is a rare neurological disorder of probably autoimmune origin. Most cases are associated with a remote neoplasm or a viral infection; however in some instances no underlying aetiology can be demonstrated. We report the presence of anti-glutamic acid decarboxylase antibodies (anti-GAD Abs) in the serum and CSF of a patient with idiopathic OMS. Treatment with intravenous immunoglobulin led to a remarkable clinical improvement with parallel reduction of anti-GAD titers. Anti-GAD Abs have been associated with several neurological syndromes. They could also be responsible for the clinical triad of OMS, by impairing GABAergic transmission in specific brainstem and cerebellar circuits. We propose that testing for anti-GAD Abs should be performed in OMS, especially when no other aetiological association can be demonstrated.

Downbeat nystagmus (DBN) is the most frequent form of acquired persisting fixation nystagmus. It is hypothesized to occur when physiological inhibitory cerebellar input, namely of the flocculus, to the vestibular nuclei is inhibited. The second most frequent form of acquired nystagmus is upbeat nystagmus (UBN). UBN is probably caused by an imbalance of vertical vestibulo-ocular reflex tone. GABA-ergic substances like baclofen have been used to treat DBN and UBN, but they have had only moderate success. Animal experiments have shown that aminopyridines [3,4-diaminopyridine (3,4-DAP) and 4-aminopyridine (4-AP)], nonselective blockers of the Kv family of voltage-gated potassium channels, increase Purkinje-cell (PC) excitability. It was assumed that such enhancement of PC activity could restore to normal levels the inhibitory influence of the cerebellar cortex on vertical eye movements. On the basis of these assumptions, we evaluated the efficacy and underlying mechanisms of aminopyridines in DBN and UBN as well as in another cerebellar disorder with an impaired PC function: episodic ataxia type 2 (EA2), which is caused by mutations of the PQ-calcium channel. In a placebo-controlled trial on 17 patients we demonstrated that 3,4-DAP significantly reduces the intensity of DBN. This was confirmed in a recent study with 4-AP, which also showed that 4-AP restores gaze-holding ability independently of fixation in DBN. The efficacy of 4-AP in UBN was demonstrated in single patients. Finally, in an open trial on three patients with EA2 we showed that 4-AP prevents attacks of ataxia. This was also found in an animal model (the tottering mouse) of EA2. The clinical efficacy of 4-AP in EA2 is being further evaluated in an ongoing randomized controlled crossover trial. In conclusion, the use of aminopyridines in DBN, UBN, and EA2 is a new treatment principle for vestibular, cerebellar, and ocular motor disorders.

Background: Corneal stings from the sea nettle (Chrysaora quinquecirrha) indigenous to the Chesapeake Bay are usually painful but self-limited injuries, with resolution in 24 to 48 hours., Methods: Five patients who developed unusually severe and prolonged iritis and intraocular pressure elevation after receiving corneal sea nettle stings were followed for 2 to 4 years., Results: Decreased visual acuity, iritis, and increased intraocular pressure (32 to 48 mmHg) were noted in all cases. Iritis responded to topical corticosteroids and resolved within 8 weeks. Elevated intraocular pressure responded to topical beta blockers and oral carbonic anhydrase inhibitors. Mydriasis (4 of 5 cases), decreased accommodation (2 of 5 cases), peripheral anterior synechiae (2 of 5 cases), and iris transillumination defects (3 of 5 cases) also were noted. Mydriasis and decreased accommodation persisted for 5 months in 1 case and for more than 2 years in another. One patient has chronic unilateral glaucoma. Visual acuity returned to normal in all cases., Conclusions: The precise relationship between sea nettle venom and the observed clinical responses is not known. Corneal jellyfish stings usually produce a brief and self-limited reaction, but they do have the potential for long-term sequelae.