46 research outputs found
Rare express saccades in elderly fallers
Q Yang1, T T Lê1, E Debay1, C Orssaud2, G Magnier3, Z Kapoula11Groupe IRIS Vision and Motricité Binoculaire, CNRS, Service d’Ophtalmologie-ORL-Stomatologie; 2Service d’Ophtalmologie, Hôpital Européen Georges Pompidou, Paris, France; 3Hôpital de gériatrie Henry Dunant, Paris, FranceObjective: To examine horizontal saccades in elderly subjects with falling history; prior extensive screening was done to recruit subjects with falling history in the absence of pathology.Methods: Twelve elderly with falling history were tested. Two testing conditions were used: the gap (fixation target extinguishes prior to target onset) and the overlap (fixation stays on after target onset) paradigms. Each condition was run at three viewing distances −20 cm, 40 cm, and 150 cm, corresponding to convergence angle at 17.1°, 8.6°, and 2.3°, respectively. Eye movements were recorded with the photoelectric IRIS (Skalar medical).Results: (i) like in healthy elderly subjects, elderly with falling history produce shorter latencies in the gap paradigm than in the overlap paradigm; (ii) their latencies are shorter at near distances (20 and 40 cm) relative to 150 cm for both paradigms; (iii) the novel result is that they fail to produce express latencies even in the conditions (near viewing distance and the gap task) known to promote high rates of express in adults (25%) or in healthy elderly (20%). Seven from the 10 healthy elderly produced express saccades at rates >12%, while 9 of the 12 older subjects with falling history showed no express saccades at all; the remaining 3 subjects showed low rates <12%.Conclusion: The quasi paucity of express saccades could be due to the disequilibrium of complex cortical/subcortical networks needed for making express saccades. The results support models suggesting specific network for express saccades; missing of such optomotor reflex may go along with missing other reflexes as well increasing the chances of falling.Keywords: elderly, falling, saccades, gap/overlap, express saccad
Central Crosstalk for Somatic Tinnitus: Abnormal Vergence Eye Movements
Frequent oulomotricity problems with orthoptic testing were reported in patients with tinnitus. This study examines with objective recordings vergence eye movements in patients with somatic tinnitus patients with ability to modify their subjective tinnitus percept by various movements, such as jaw, neck, eye movements or skin pressure.Vergence eye movements were recorded with the Eyelink II video system in 15 (23–63 years) control adults and 19 (36–62 years) subjects with somatic tinnitus.1) Accuracy of divergence but not of convergence was lower in subjects with somatic tinnitus than in control subjects. 2) Vergence duration was longer and peak velocity was lower in subjects with somatic tinnitus than in control subjects. 3) The number of embedded saccades and the amplitude of saccades coinciding with the peak velocity of vergence were higher for tinnitus subjects. Yet, saccades did not increase peak velocity of vergence for tinnitus subjects, but they did so for controls. 4) In contrast, there was no significant difference of vergence latency between these two groups.The results suggest dysfunction of vergence areas involving cortical-brainstem-cerebellar circuits. We hypothesize that central auditory dysfunction related to tinnitus percept could trigger mild cerebellar-brainstem dysfunction or that tinnitus and vergence dysfunction could both be manifestations of mild cortical-brainstem-cerebellar syndrome reflecting abnormal cross-modality interactions between vergence eye movements and auditory signals
PET study of voluntary saccadic eye movements in humans: basal ganglia-thalamocortical system and cingulate cortex involvement
Urrets−Zavalia syndrome as a complication of ocular hypotonia due to intravenous cidofovir treatment
Dépistage et prévention des neuropathies optiques toxiques aux anti-mycobactériens : proposition de recommandations
International audienceWhile treatment of pulmonary infections by Mycobacterium tuberculosis is currently only rarely the cause of iatrogenic complications, treatment of atypical mycobacterial infections often requires prolonged treatment duration, which can lead to toxic optic neuropathies. This review summarizes the indications for such prolonged treatment and risk factors for toxic optic neuropathies when using ethambutol, isoniazid and/or linezolid and proposes customized screening recommendations.Tandis que le traitement des infections pulmonaires à Mycobacterium tuberculosis n’est plus que rarement pourvoyeur de complications iatrogéniques, la prise en charge des infections à mycobactéries atypiques requiert souvent des traitements prolongés qui peuvent se compliquer de neuropathies optiques toxiques. Cette revue récapitule les indications à ces traitements prolongés, les situations à risque de neuropathie optique toxique en cas d’utilisation d’éthambutol, d’isoniazide et/ou de linézolide, et propose des protocoles de dépistage adaptés à chaque situation