The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Konrad P Weber - One of the best experts on this subject based on the ideXlab platform.
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Incomitance of Ocular Rotation Axes in Trochlear Nerve Palsy
2015Co-Authors: Konrad P Weber, Antonella A Palla, Klara A Landau, Thomas Haslwanter AAbstract:ABSTRACT: Strabismus due to Palsy of a single muscle in one eye is always in-comitant, which is a consequence of Hering’s law of equal innervation. We asked whether this law had similar consequences on the orientation of ocular rotation axes. Patients with unilateral Trochlear Nerve Palsy were oscillated about the nasooccipital ( = roll) axis (±35◦, 0.3 Hz), and monocularly fixed on targets on a head-fixed Hess screen. Both the covered and uncovered eyes were measured with dual search coils. The rotation axis of the covered eye (paretic or healthy) tilted more nasally from the line of sight when gaze was directed toward the side of the healthy eye. The rotation axis of the viewing eye (paretic or healthy), however, remained roughly aligned with the line of sight. We con-clude that incomitance due to eye muscle Palsy extends to ocular rotation axes during vestibular stimulation
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dynamic aspects of Trochlear Nerve Palsy
Progress in Brain Research, 2008Co-Authors: Dominik Straumann, Christopher J Bockisch, Konrad P WeberAbstract:Trochlear Nerve Palsy leads to kinematic aberrations of both the paretic and the unaffected eye. During dynamic head roll, the rotation axis of the covered paretic or unaffected eye deviates inward, while the rotation axis of the viewing paretic or unaffected eye aligns with the line of sight; this convergence of rotation axes increases with gaze moving in the direction of the unaffected eye. During downward saccades, the trajectories of both eyes curve towards the unaffected side; these curvatures increase when the head is rolled to the affected side and gaze directed to the unaffected side. Hence, during both vestibular evoked and saccadic ocular movements, the unaffected eye shows similar kinematic aberrations as the paretic eye. While aberrations of the paretic eye can be explained by decreased force of the superior oblique (SO) muscle, aberrations of the unaffected eye may be due to increased force parallel to the paretic SO in the unaffected eye in accordance with Hering's law. This law, which forms the basis of conjugate eye movements, also seems to govern eye displacements in unilateral eye muscle Palsy.
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ocular rotation axes during dynamic bielschowsky head tilt testing in unilateral Trochlear Nerve Palsy
Investigative Ophthalmology & Visual Science, 2004Co-Authors: Konrad P Weber, Klara Landau, Antonella Palla, Thomas Haslwanter, Dominik StraumannAbstract:RESULTS. The rotation axis of the viewing paretic or unaffected eye was nearly parallel to the line of sight. The rotation axis of the covered fellow eye, however, was tilted inward relative to the other axis. This convergence of axes increased with gaze toward the unaffected side. Over entire cycles of head roll, the rotation axis of either eye remained relatively stable in both the viewing and covered conditions. CONCLUSIONS. In patients with uTNP, circular gaze trajectories of the covered paretic or unaffected eye during dynamic BHT are a direct consequence of the nasal deviation of the rotation axis from the line of sight. This, in turn, is a geometrical result of decreased force by the superior oblique muscle (SO) of the covered paretic eye or, according to Hering’s law, increased force parallel to the paretic SO in the covered unaffected eye. The horizontal incomitance of rotation axes along horizontal eye positions can be explained by the same mechanism. (Invest Ophthalmol Vis Sci. 2004;45:455‐ 465) DOI:10.1167/
Dominik Straumann - One of the best experts on this subject based on the ideXlab platform.
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dynamic aspects of Trochlear Nerve Palsy
Progress in Brain Research, 2008Co-Authors: Dominik Straumann, Christopher J Bockisch, Konrad P WeberAbstract:Trochlear Nerve Palsy leads to kinematic aberrations of both the paretic and the unaffected eye. During dynamic head roll, the rotation axis of the covered paretic or unaffected eye deviates inward, while the rotation axis of the viewing paretic or unaffected eye aligns with the line of sight; this convergence of rotation axes increases with gaze moving in the direction of the unaffected eye. During downward saccades, the trajectories of both eyes curve towards the unaffected side; these curvatures increase when the head is rolled to the affected side and gaze directed to the unaffected side. Hence, during both vestibular evoked and saccadic ocular movements, the unaffected eye shows similar kinematic aberrations as the paretic eye. While aberrations of the paretic eye can be explained by decreased force of the superior oblique (SO) muscle, aberrations of the unaffected eye may be due to increased force parallel to the paretic SO in the unaffected eye in accordance with Hering's law. This law, which forms the basis of conjugate eye movements, also seems to govern eye displacements in unilateral eye muscle Palsy.
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ocular rotation axes during dynamic bielschowsky head tilt testing in unilateral Trochlear Nerve Palsy
Investigative Ophthalmology & Visual Science, 2004Co-Authors: Konrad P Weber, Klara Landau, Antonella Palla, Thomas Haslwanter, Dominik StraumannAbstract:RESULTS. The rotation axis of the viewing paretic or unaffected eye was nearly parallel to the line of sight. The rotation axis of the covered fellow eye, however, was tilted inward relative to the other axis. This convergence of axes increased with gaze toward the unaffected side. Over entire cycles of head roll, the rotation axis of either eye remained relatively stable in both the viewing and covered conditions. CONCLUSIONS. In patients with uTNP, circular gaze trajectories of the covered paretic or unaffected eye during dynamic BHT are a direct consequence of the nasal deviation of the rotation axis from the line of sight. This, in turn, is a geometrical result of decreased force by the superior oblique muscle (SO) of the covered paretic eye or, according to Hering’s law, increased force parallel to the paretic SO in the covered unaffected eye. The horizontal incomitance of rotation axes along horizontal eye positions can be explained by the same mechanism. (Invest Ophthalmol Vis Sci. 2004;45:455‐ 465) DOI:10.1167/
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primary position and listing s law in acquired and congenital Trochlear Nerve Palsy
Investigative Ophthalmology & Visual Science, 2003Co-Authors: Dominik Straumann, Klara Landau, Heimo Steffen, O Bergamin, Ananth V Mudgil, Mark F Walker, David L Guyton, David S ZeeAbstract:PURPOSE. In ocular kinematics, the primary position (PP) of the eye is defined by the position from which movements do not induce ocular rotations around the line of sight (Helmholtz). PP is mathematically linked to the orientation of Listing’s plane. This study was conducted to determine whether PP is affected differently in patients with clinically diagnosed congenital (conTNP) and acquired (acqTNP) Trochlear Nerve Palsy. METHODS. Patients with unilateral conTNP (n 25) and acqTNP (n 9) performed a modified Hess screen test. Threedimensional eye positions were recorded with dual search coils. RESULTS. PP in eyes with acqTNP was significantly more temporal (mean: 21.2°) than in eyes with conTNP (6.8°) or healthy eyes (7.2°). In the pooled data of all patients, the horizontal location of PP significantly correlated with vertical noncomitance with the paretic eye in adduction (R 0.59). Using a computer model, PP in acqTNP could be reproduced by a neural lesion of the superior oblique (SO) muscle. An additional simulated overaction of the inferior oblique (IO) muscle moved PP back to normal, as in conTNP. Lengthening the SO and shortening the IO muscles could also simulate PP in conTNP. CONCLUSIONS. The temporal displacement of PP in acqTNP is a direct consequence of the reduced force of the SO muscle. The reversal of this temporal displacement of PP, which occurs in some patients with conTNP, can be explained by a secondary overaction of the IO muscle. Alternatively, length changes in the SO and IO muscles, or other anatomic anomalies within the orbit, without a neural lesion, may also explain the difference in location of PP between conTNP and acqTNP. (Invest Ophthalmol Vis Sci. 2003;44:4282‐ 4292) DOI:10.1167/iovs.021181
Nancy J. Newman - One of the best experts on this subject based on the ideXlab platform.
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Schwannoma in patients with isolated unilateral Trochlear Nerve Palsy.
American journal of ophthalmology, 1999Co-Authors: Andrew S Feinberg, Nancy J. NewmanAbstract:Abstract PURPOSE: To describe the clinical features of patients with isolated unilateral Trochlear Nerve Palsy secondary to imaging-defined schwannoma of the Trochlear Nerve. METHODS: A chart review of all patients seen at the Neuro-Ophthalmology Unit at Emory University since 1989. Of 221 patients with Trochlear Nerve Palsy, six had a lesion consistent with a Trochlear Nerve schwannoma. RESULTS: The six patients had isolated unilateral Trochlear Nerve Palsy. Duration of diplopia before diagnosis averaged 6 months. Magnetic resonance imaging demonstrated circumscribed, enhancing lesions along the cisternal course of the Trochlear Nerve, all measuring less than 5 mm in greatest dimension. Five of the patients were seen in follow-up, over periods ranging from 11 to 26 months from initial presentation (mean, 15.6 months; standard deviation, 6.0 months). All of these patients remained stable except one, who was slightly worse at 15 months by clinical measurements and magnetic resonance imaging. None of these patients have developed additional symptoms or signs of cranial Nerve or central nervous system involvement. CONCLUSIONS: The differential diagnosis of an isolated unilateral fourth cranial Nerve Palsy should include an intrinsic neoplasm of the Trochlear Nerve. Magnetic resonance imaging is useful, both for diagnosis and follow-up. These patients can remain stable and may not require neurosurgical intervention.
Daniel M. Jacobson - One of the best experts on this subject based on the ideXlab platform.
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Isolated Trochlear Nerve Palsy in patients with multiple sclerosis
Neurology, 1999Co-Authors: Daniel M. Jacobson, Mark L. Moster, E. R. Eggenberger, Steven Galetta, Grant T. LiuAbstract:The authors describe five patients with Trochlear Nerve Palsy and MS to characterize this rare association. In two patients, Trochlear Nerve Palsy was the initial clinical manifestation of MS. In the other three patients, this sign occurred after previous neurologic events. MRI did not identify a lesion of the fourth Nerve nucleus or fascicle. Ophthalmoplegia resolved within 2 months in four of the five patients. A reason this association is rare is that the fascicular course of the Trochlear Nerve is exposed to little myelin.
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Transient Trochlear Nerve Palsy following anterior temporal lobectomy for epilepsy
Neurology, 1995Co-Authors: Daniel M. Jacobson, John J. Warner, Kevin H. RugglesAbstract:Three of 22 patients (14%) who underwent anterior temporal lobectomy for treatment of medically intractable epilepsy at our institution from July 1987 through July 1993 experienced diplopia immediately after surgery. We found ipsilateral paresis of the superior oblique muscle in all three patients. Their ophthalmoplegia resolved completely within 14 weeks. We did not observe any new structural or ischemic changes on postoperative MRIs to account for their deficits. Trochlear Nerve Palsy--not oculomotor Nerve Palsy, as is reported in most reference texts--is a relatively common cause of transient diplopia following temporal lobectomy. Indirect (ie, traction) injury of the Trochlear Nerve is a plausible mechanism that would explain this complication.
Hweizu Wang - One of the best experts on this subject based on the ideXlab platform.
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painful fourth cranial Nerve Palsy caused by posteriorly draining dural carotid cavernous sinus fistula
Journal of the Formosan Medical Association, 2000Co-Authors: Rongkung Tsai, Hsinyi Chen, Hweizu WangAbstract:A 65-year-old man with a dural carotid-cavernous fistula (DCCF) presented with sudden onset of painful Trochlear Nerve paresis. Typical signs of DCCF including conjunctival arterialization, chemosis, and proptosis did not become manifest until 4 months later. This unusual presentation of DCCF was caused by drainage of the fistula posteriorly into the inferior petrosal sinus with low flow. With this condition, patients may present with Trochlear Nerve Palsy without a red eye. Although rare, DCCF must be considered in patients presenting with isolated painful Trochlear Palsy.
