Dorsal Visual Pathway Changes in Patients with Comitant Extropia

BACKGROUND: Strabismus is a disorder in which the eyes are misaligned. Persistent strabismus can lead to stereopsis impairment. The effect of strabismus on human brain is not unclear. The present study is to investigate whether the brain white structures of comitant exotropia patients are impaired using combined T1-weighted imaging and diffusion tensor imaging (DTI). PRINCIPAL FINDINGS: Thirteen patients with comitant strabismus and twelve controls underwent magnetic resonance imaging (MRI) with acquisition of T1-weighted and diffusion tensor images. T1-weighted images were used to analyze the change in volume of white matter using optimized voxel-based morphology (VBM) and diffusion tensor images were used to detect the change in white matter fibers using voxel-based analysis of DTI in comitant extropia patients. VBM analysis showed that in adult strabismus, white matter volumes were smaller in the right middle occipital gyrus, right occipital lobe/cuneus, right supramarginal gyrus, right cingulate gyrus, right frontal lobe/sub-gyral, right inferior temporal gyrus, left parahippocampa gyrus, left cingulate gyrus, left occipital lobe/cuneus, left middle frontal gyrus, left inferior parietal lobule, and left postcentral gyrus, while no brain region with greater white matter volume was found. Voxel-based analysis of DTI showed lower fractional anisotropy (FA) values in the right middle occipital gyrus and right supramarginal gyrus in strabismus patients, while brain region with increased FA value was found in the right inferior frontal gyrus. CONCLUSION: By combining VBM and voxel-based analysis of DTI results, the study suggests that the dorsal visual pathway was abnormal or impaired in patients with comitant exotropia

Binocular and monocular measurements of subjective visual vertical in vestibular loss.

The objective of this study was to investigate the possibility to omit the time-consuming monocular vision measurement in the subjective visual vertical (SVV) test by demonstrating that there is no difference in the results between binocular and monocular measurements. Thirty-one patients with unilateral vestibular schwannoma and 20 normal subjects as controls were involved. Both binocular and monocular measurements of SVV were performed. The main outcome of this study was the difference in the results of SVV between binocular and monocular measurements. There were no significant differences in the tilts of the SVV between binocular and monocular measurements in vestibular schwannoma patients as well as in the controls. Abnormal tilts of SVV may be evaluated precisely only by binocular vision instead of monocular vision

Quantitative Bestimmung des Endolymphatischen Hydrops beim Meerschweinchen mittels MRT nach i.v.-Kontrastmittelapplikation

Beim Ménière'schen Syndrom wird ein endolymphatischer Hydrops als Ausweitung des endolymphatischen Systems nachgewiesen. Ein endolymphatischer Hydrops konnte in der Vergangenheit beim Menschen nur post-mortem in Felsenbeinpräparaten festgestellt werden, in neueren Untersuchungen konnte anhand MRT-Bildgebung eine volumetrische Quantifizierung des endolymphatischen Hydrops ermöglicht werden. Zur Untersuchung von potentiellen Medikamenten ist ein Tiermodell die chirurgische Obliteration des Ductus und des Saccus endolymphaticus. Für eine longitudinale Quantifizierung der Innenohrräume Scala tympani, Scala vestibuli und Scala media erfolgten hier beim Meerschweinchen am 7 T Kleintier-MRT die Messung der kontrastverstärkten Innenohrsignalintensität. Dazu wurde Gadovist über einen i.v. Katheter am Hinterbein im Bolus als Kontrastmittel injiziert. 1,5 h später erfolgte die MRT-Bildgebung mit einer lokalen Hirnspule, welche auf das zu untersuchende Ohr platziert wurde. 6 Meerschweinchen wurden jeweils vor der einseitigen Obliteration und 1, 3, 5 und 7 Wochen nach der Induktion im MRT gemessen. Eine Woche nach chirurgischer Obliteration war eine deutliche Vergrößerung der Scala media erkennbar und auch quantifizierbar. Bei 4 Tieren entwickelte sich der Hydrops zwischen der 1. und 5. Woche nach Obliteration zurück, bei zwei Tieren war der Hydrops nach 7 Wochen noch messbar. Am Ende des Beobachtungszeitraums wurde die Innenohrfunktion elektrophysiologisch untersucht, hier ergaben sich keine Auffälligkeiten. Die Innenohre wurden entnommen, fixiert und morphologisch aufgearbeitet, um den Hydrops quantitativ zu bestimmen. Die histologische Aufarbeitung ergab eine gute Übereinstimmung zu den MRT-Befunden.Der Erstautor gibt keinen Interessenkonflikt an

Amplitude and area ratios of summating potential/action potential (SP/AP) in Meniere\u27s disease.

CONCLUSIONS: Our results suggest that summating potential/action potential (SP/AP) area ratio may not necessarily have higher sensitivity in the diagnosis of endolymphatic hydrops of Meniere\u27s disease (MD) than SP/AP amplitude ratio in transtympanic electrocochleography (ECochG). OBJECTIVE: Recent studies suggested that SP/AP area curve ratio was more sensitive to endolymphatic hydrops in comparison with SP/AP amplitude ratio in extratympanic ECochG. The purpose of the present study was to evaluate the utility of the SP/AP area curve ratio in transtympanic ECochG for the diagnosis of MD. PATIENTS AND METHODS: A retrospective chart review of 198 patients (209 ears) was conducted in cases of MD. RESULTS: With regard to SP/AP amplitude ratio, 57.1% in definite cases of MD (group 1), 39.6% in probable cases of MD (group 2), and 50.0% in the cases who had transformed from probable MD to definite MD (group 3) showed abnormally high values, respectively. Abnormally high values were observed in 43.9%, 27.7%, and 30.0% in SP/AP area ratio in groups 1, 2, and 3, respectively, indicating that abnormal values were observed more frequently in the amplitude ratio than in the area ratio in all three groups