PubMed Health⌕ Search

Biomedical subjects

D Zee

Publications and source records attributed to D Zee.

16 recordsLinked to original sources
PubMed2003

Accuracy of clinical detection of INO in MS: corroboration with quantitative infrared oculography.

The authors compared the accuracy of clinical detection (by 279 physician observers) of internuclear ophthalmoparesis (INO) with that of quantitative infrared oculography. For the patients with mild adduction slowing, INO was not identified by 71%. Intermediate dysconjugacy was not detected by 25% of the evaluators. In the most severe cases, INO was not identified by only 6%. Oculographic techniques significantly enhance the precision of INO detection compared to the clinical exam.

Diagnostic Techniques, Ophthalmological↗
PubMed1998

Clinical features of autosomal dominant congenital nystagmus linked to chromosome 6p12.

PURPOSE: To describe the clinical features of a large pedigree with autosomal dominant congenital nystagmus linked to chromosome 6p12. METHODS: In a prospective evaluation of 54 living family members in a single pedigree, 21 persons were affected with autosomal dominant congenital nystagmus, and clinical examinations were performed on 14. Selected persons underwent further studies, including electroretinography, scanning laser ophthalmoscopy, nerve fiber layer studies, visual evoked potential studies, and eye movement recordings. RESULTS: Among seven affected persons whose parents were able to report whether the nystagmus was present congenitally, onset at birth was noted in two persons and between 3 and 6 months in five persons. Best-corrected binocular Snellen visual acuity ranged from 20/30 to 20/100, with a mode of 20/50. Strabismus was present in 14 examined patients (36%). Eye movement recordings, performed on five persons, included asymmetric pendular (three), asymmetric pendular combined with dual waveform jerk (one), and unidirectional jerk nystagmus (one). CONCLUSIONS: Autosomal dominant congenital nystagmus represents a disorder with variable expressivity. While onset is typically during infancy, it can be noted at birth. Intrafamilial variation in visual acuity, ocular alignment, and nystagmus waveform suggests a role for modifying influences on expression of disease.

Adult↗
PubMed1996

Olivocochlear innervation of inner and outer hair cells during postnatal maturation: an immunocytochemical study.

Changes in the expression of several neurochemical markers associated with either axonal growth (GAP-43), synaptic vesicles (synaptophysin), or the cholinergic population of lateral olivocochlear (OC) efferents were investigated in the postnatal cochlea of hamsters. Growth-associated protein was expressed in the neonatal cochlea but not in the adult; immunoreactivity was found below inner hair cells (IHCs) from postnatal day (P) 2 through P14 and below outer hair cells (OHCs) from P5 to P14. In contrast, synaptophysin was expressed in both the neonate and adult cochlea; immunoreactivity was found below IHCs around P4 and below OHCs at P5. Both GAP-43 and synaptophysin immunoreactivities occurred first below IHCs in basal regions of the cochlea. Efferent fibers containing calcitonin gene-related peptide (CGRP) immunoreactivity were identified as early as P4 within the cochlear nerve but were not observed underneath IHCs until P7. Similar to GAP-43 and synaptophysin immunoreactivity, CGRP expression followed a basal to apical gradient; however, expression below OHCs appeared restricted to apical regions. These data raise the possibility that efferents expressing growth proteins and efferents expressing synaptic vesicle proteins co-exist during the first postnatal week. Furthermore, it is hypothesized that CGRP-containing lateral OC neurons form part of a later, secondary innervation to the cochlea.

Animals↗
PubMed1994

Rotational kinematics of the human vestibuloocular reflex. I. Gain matrices.

1. This series of three papers aims to describe the three-dimensional, kinematic input-output relations of the rotational vestibuloocular reflex (VOR) in humans, and to identify the functional advantages of these relations. In this first paper the response to sinusoidal rotation in darkness at 0.3 Hz, maximum speed 37.5%/s, was quantified by the use of the three-dimensional analogue of VOR gain: a 3 x 3 matrix where each element describes the dependence of one component (torsional, vertical, or horizontal) of eye velocity on one component of head velocity. 2. The three matrix elements indicating collinear gains (i.e., dependence of torsional eye velocity on torsional head velocity, vertical on vertical, and horizontal on horizontal) were smaller than the -1's required for optimal retinal image stabilization. Of these three the torsional gain was weakest: -0.37 for rotation about an earth-vertical axis, versus -0.73 and -0.64 for vertical and horizontal gains. Matrix elements indicating cross talk were mostly negligible. There was a tendency to leftward eye rotation in response to clockwise head motion, but this was not statistically significant. 3. VOR responses were compared for rotation about earth-vertical and earth-horizontal axes. The varying otolith input due to the rotation of the gravity vector relative to the head during earth-horizontal axis rotation made no difference to the collinear gains. 4. There were no consistent phase leads or lags except for a torsional phase lead of up to 10 degrees, usually more marked for clock-wise head rotation versus counterclockwise, and for oblique axis rotations versus purely torsional. 5. Torsional gain was magnified, averaging -0.52, when the torsional component of head rotation was only a small part of a predominantly vertical or horizontal rotation, i.e., when the axis of head rotation was near the frontal plane. Because most natural head rotations occur about such axes, the torsional VOR is probably somewhat stronger than the response to pure torsion would suggest. 6. The speed of eye rotation in response to a given stimulus varied widely among subjects, but the direction of rotation was much more uniform. For head rotations about oblique axes out of the frontal plane, there was a systematic misalignment of eye and head axes, with eye axes tilted toward the frontal plane. These findings can be explained on the basis of a strategy where the VOR balances the muscular effort of rotating the eyes against the cost of retinal slip.

Acceleration↗
PubMed1993

Unimpaired verbal memory and oculomotor control in asymptomatic adults with the genetic marker for Huntington's disease.

OBJECTIVE: To determine whether asymptomatic individuals at very high genetic risk for Huntington's disease (HD) have demonstrable cognitive or oculomotor abnormalities. DESIGN: A case-control study was employed. Presence of the chromosome-4 DNA marker linked to the HD phenotype was the criterion for HD risk. SETTING: The Baltimore Huntington's Disease Project Presymptomatic Testing Program at The Johns Hopkins University School of Medicine, Baltimore, Md. PARTICIPANTS: Seventy-six asymptomatic adults at risk for HD, voluntarily enrolled for genetic testing, and determined by clinical examination to be free of major psychiatric disorder or evidence of HD. Twenty were determined to be at greater than or equal to 95% risk for HD; 56 were at less than or equal to 5% risk [corrected]. MEASURES: The Hopkins Verbal Learning Test was used to assess verbal learning and memory. Oculomotor functioning was assessed using Novel-Stimulus, Mirror-Stimulus, and Predictive-Saccade paradigms. Outcome measures included number of correctly recalled words, recognition accuracy, and response bias, as well as saccade latency and number of errors on the Mirror-Stimulus Test. RESULTS: With one exception, all participants performed within the normal range on the Hopkins Verbal Learning Test. In a blind follow-up examination of the individual who performed aberrantly on the Hopkins Verbal Learning Test, she exhibited neurologic and psychiatric changes sufficient for a clinical diagnosis of HD. There were no group differences on the tests of oculomotor functioning. CONCLUSIONS: Young, asymptomatic adults at very high genetic risk for HD are unimpaired in tests of verbal learning and memory and oculomotor functioning.

Adult↗
PubMed1987

Linear head displacement measured by the otoliths can be reproduced through the saccadic system.

Normal subjects seated on a moving cart have been submitted to horizontal linear accelerations in the frontal plane. They were shown an earth-fixed target at a distance of 63 cm before the onset of cart motion, which occurred in total darkness. They were asked to keep their gaze on the imagined target. The main result is that, in spite of a low gain otolith-ocular reflex, they could reproduce their motion with great accuracy by saccades (a small overestimation was, however, observed). It is concluded that otolith information is used by probably cortical spatial analysers which can derive a precise measurement of linear displacement and feed this information in the saccadic system.

Acceleration↗
PubMed1981

Central ocular motor abnormalities in Duane's retraction syndrome.

Duane's retraction syndrome (DRS) is a congenital eye movement disorder characterized by marked limitation or absence of abduction, variable limitation of adduction, and narrowing of the palpebral fissure with retraction of the globe on attempted adduction. We have recently recorded and quantitated ocular motility in five patients with unilateral DRS. In all patients, abduction of the affected eye was greatly limited, whereas adduction was limited, whereas adduction was limited to a lesser degree. Abnormalities in saccadic velocities were found in both the affected eye and the sound eye. Results of testing of the vestibulo-ocular reflex, optokinetic nystagmus, and optokinetic afternystagmus showed notable asymmetry. Our results suggest that DRS is produced by a primary brainstem abnormality involving premotor structures.

Adolescent↗