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The Effect of Mesencephalic Lesions on Three-Dimensional Eye Movements
Published in Michael Fetter, Thomas Haslwanter, Hubert Misslisch, Douglas Tweed, Three-Dimensional Kinematics of Eye, Head and Limb Movements, 2020
Christoph Helmchen, Leonard Fuhry, Holger Rambold, Ulrich Büttner
In this chapter we will focus on tonic and dynamic aspects of torsional eye movement deficits after mesencephalic lesions in patients and monkeys. Lesion studies in the mesencephalon of cat (Fukushima et al., 1992) and monkey (Crawford et al., 1991, Crawford and Vilis 1992; Crawford 1994; Suzuki et al., 1995; Vilis et al., 1989) produce contraversive (contralesional) tonic ocular torsion. This tonic ocular torsion in animal experiments can be best shown by the parallel shift of Listing’s plane. According to Listing’s law all axes of rotations, around which eye movements move from a particular reference position (primary position) to any other position in space, come to lie in one plane, i.e. Listing’s plane, provided the head is upright and stationary. Thus, a shift of Listing’s plane indicates a torsional deviation from the resting torsional position. In animal experiments, this torsional offset can be quantitatively measured by performing reversible, temporary midbrain lesions providing normal and pathological torsional eye position values. Studying patients usually does not allow to analyse the shift of Listing’s plane since there are no torsional values prior the lesion available for the individual patient. Using tundoscopy, clinical studies have shown contraversive (contralesional) tonic binocular torsion of the eyes up to 25 deg (Dieterich and Brandt, 1993) after mesencephalic lesions. For clinicians, tonic ocular torsion in mesencephalic disease is suspected in the case of an ocular tilt reaction (OTR) consisting of the triad of a contralesional head tilt, a vertical skew deviation with contralateral hypotropia and contraversive conjugate ocular torsion (Dieterich and Brandt, 1993).
Subjective visual vertical and horizontal: bucket test normative
Published in Hearing, Balance and Communication, 2021
Teja Deepak Dessai, Anaswara Prasannan
Several authors have used SVV and SVH to diagnose subjects with vestibular pathology and the clinical application of these have served to identify the lesions in otolithic organs from the vestibular system through medulla and mesencephalon [3]. The normative across age from the current study will guide in coming to the diagnosis of any acute peripheral vestibular pathologies. Any deviation from the given normative values indicate the presence of abnormal tilt. The direction of tilt will help to determine the side of lesion. Abnormal SVV tilts will occur on the side of peripheral vestibular dysfunction. This is an incidental indicator of the ocular tilt reaction in response to the vestibular disorder [15]. However, in central pathologies such as brainstem lesions and tegmental pontomedullary, the ocular tilts are observed on the side of lesion [16].
Bilateral Fascicular Third Nerve Palsy in Posterior Circulation Stroke
Published in Neuro-Ophthalmology, 2019
Olaf Eberhardt, Mirjam Hermisson, Gisela Eberle-Strauss, Helge Topka
Dysarthria subsided after a few days. After discharge from the hospital and during the rehabilitation phase that followed, the sequelae of bilateral third cranial nerve palsy prevailed. The most disturbing feature was complete ptosis that required mechanical aids, e.g. adhesive strips, to keep either eye open. Only the right eye could be moved almost until midline while the left eye remained in abduction. Both pupils were mydriatic, on the right more than on the left side, and no reaction to light was present on the right side. There was exotropia of the right eye and vertical eye divergence. Convergence paresis and complete vertical gaze palsy were also present. In later examinations, an incomplete ocular tilt reaction was suggested by a slight skew deviation of the left eye over the right one and a slight ocular torsion to the right, without head tilt. Due to oculomotor disturbance, there was dizziness and unsteadiness of gait. Monopedal stance on the left side was unsteady, but balance and postural control improved after dedicated physical therapy. Slightly reduced fine motor skills and disturbed diadochokinesis of the left hand were treated by ergotherapeutic intervention.
Acute isolated utricular lesion
Published in Hearing, Balance and Communication, 2019
Ocular tilt reaction is rarely encountered in peripheral lesions. It is usually sign of central graviceptive lesion, but it has been described in some patients with complete peripheral vestibular loss [7]. Partial ocular tilt reaction is more frequent finding, since skew deviation is rarely present [8]. Herein presented patient had head tilt to the lesioned side and subjective visual vertical significantly shifted to the same side.