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Neuro-Ophthalmological Findings in Patients with Posterior Circulation Stroke
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
When the PPRF and the MLF are both involved on the same side, the resulting ophthalmoplegia is severe and patients can only move the contralateral eye in abduction to one side. This abnormality was named the “one and a half syndrome” by Fisher.12,18 If conjugate gaze to one side is given a score of 1, normal patients with intact horizontal gaze have a score of 2. PPRF lesions abolish the conjugate gaze to one side, the ipsilateral side, and MLF lesions abolish gaze of the adducting eye to the contralateral side, removing 1/2 of gaze to that side. In total 1 and 1/2 of the total 2 points for horizontal gaze are lost. The OTR is more common in unilateral pontine tegmental lesions than in bilateral lesions.
Cranial Neuropathies II, III, IV, and VI
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Tanyatuth Padungkiatsagul, Heather E. Moss
In addition, the nucleus of the CN VI contains the interneurons that ascend through the medial longitudinal fasciculus to innervate the contralateral medial rectus muscles in order to perform coordinated horizontal gaze. Thus, a lesion of the PPRF or CN VI nucleus causes a gaze palsy. If there is concomitant damage to the contralateral MLF, one-and-a-half syndrome occurs, which is a gaze palsy to one side with an ipsilateral INO on gaze to the other side. This is also known as paralytic pontine exotropia.
The natural history of brainstem ocular motility disorders due to vascular pathology
Published in Jan-Tjeerd de Faber, 28th European Strabismological Association Meeting, 2020
A lesion of the medial longitudinal fasciculus (MLF) will result in internuclear ophthalmoplegia (Bronstein et al. 1990) with loss/impairment of adduction of the contralateral eye due to involvement of interneurons from the ipsilateral sixth nerve nucleus to the contralateral medial rectus subnucleus. Vascular events when diffuse cause bilateral internuclear ophthalmoplegia and when more focal cause unilateral internuclear ophthalmoplegia due to the midline separation of the blood supply to the two halves of the brainstem. We reviewed two cases of internuclear ophthalmoplegia, one unilateral and one bilateral with typical characteristics of limited adduction and abducting nystagmus of the contralateral eye. Convergence was retained in both cases. A more extensive lesion of the MLF involving the ipsilateral sixth nerve nucleus will result in a one and a half syndrome with ipsilateral horizontal gaze palsy and ipsilateral loss/impairment of adduction. One of our patients was noted to have a recovering one and a half syndrome in addition to numerous other ocular motility problems.
Eight-and-a-Half Syndrome Secondary to Neurotoxoplasmosis: A Rare Case Report
Published in Neuro-Ophthalmology, 2022
Joaquim Francisco Cavalcante-Neto, Gabriel Costa dos Reis, Mateus Aragão Esmeraldo, Bianca Ratts Freitas dos Santos, Paulo Roberto Lacerda Leal, Keven Ferreira da Ponte, Gerardo Cristino-Filho, Espártaco Moraes Lima Ribeiro
The occurrence of EHS secondary to neurotoxoplasmosis has been previously reported only once.2 Also, there has been no report of neurotoxoplasmosis as the sole cause of one-and-a-half syndrome to date. MRI in our case showed a ring-enhancing lesion slight to the left of the midline in the pons on T1-weighted contrast-enhanced MRI, with perilesional vasogenic oedema on T2-weighted MRI.2,4,9 There are multiple diagnostic methods for neurotoxoplasmosis, however clinico-radiological diagnosis is usually sufficient, considering the frequent unavailability of molecular diagnosis in low- and middle-income countries and generally unnecessary use of histopathological studies, since brain biopsy may present complications, especially in immunocompromised patients.4 CNS tuberculoma, cryptococcosis, and cysticercosis are important differential diagnoses, particularly for HIV patients, presenting with similar clinico-radiological findings.9
Binocular, Accommodative and Oculomotor Alterations In Multiple Sclerosis: A Review
Published in Seminars in Ophthalmology, 2020
Amparo Gil-Casas, David P Piñero, Ainhoa Molina-Martin
INO can appear in combination with other alterations of the ocular movement, as one-and-a-half syndrome (OAHS) and its spectrum disorders. The one and a half syndrome is a horizontal movement disorder, which combines a paralysis of the ipsilateral-conjugated horizontal gaze (one) and INO (mean).54 There is a sudden onset of double vision that gets worse when looking at one end. These patients cannot move their eyes to the opposite side. Vertical and convergence movements are not affected. The one-and-a-half syndrome is caused by a lesion of unilateral tegmentum of pons, causing damage to the paramedian pontine reticular formation (PPRF), abducens nucleus and MLF ipsilateral. MS is the second most common cause of this syndrome after vascular disease.55,56 It can occur as one of the first manifestations of the disease57 or in the course of the disease.58
Eight-and-a-half syndrome caused by a pontine haemorrhage: a case report and review of the literature
Published in International Journal of Neuroscience, 2018
Nian-ge Xia, Yan-yan Chen, Jia Li, Xi Chen, Zu-sen Ye, Si-yan Chen, Zhen-guo Zhu
One-and-a-half syndrome was first coined by C. Miller Fisher to describe a combination of horizontal gaze palsy and internuclear opthalmoplegia caused by a pontine tegmentum lesion involving the median longitudinal fasciculus (MLF) and parapontine reticular formation (PPRF) [1]. The combination of one-and-a-half syndrome plus ipsilateral cranial nerve VII palsy constitutes eight-and-a-half syndrome (1½ + 7 = 8½), first described in 1998 by Eggenberger [2]. Various etiologies have been reported, including ischaemic stroke [3–8], vasculitis [9], demyelination [10,11] and brainstem tuberculoma [12]. Also, many variants of eight-and-a-half syndrome, such as nine syndrome [13], thirteen-and-a-half syndrome [14] and fifteen-and-a-half syndrome [15], have been described. In this article, we present an unusual case of eight-and-a-half syndrome combined with contralateral hemiparesis due to the pontine haemorrhage. In addition, we also discuss the related spectrum of eight-and-a-half syndrome through the literature review.