Abnormality of vergence latency in children with vertigo

Abstract

It is well known that vergence movements are important for distance appreciation, depth vision and stereopsis. Moreover, vergence movements are very probably used by the CNS during head and body motion to adjust the gain of the vestibulo-ocular reflex (VOR) according to the viewing distance. A recent clinical study of Anoh-Tanon et al. suggested that vertigo in children with normal vestibular function could be associated with abnormal vergence clinically assessed. The purpose of this study was to test this hypothesis with objective vergence eye movement recordings. We examined the latency of vergence, saccades and combined movements in twelve children with the complaint of vertigo but without vestibular abnormality. Convergence and saccades combined with convergence or with divergence had abnormally long latencies (relative to normal children of matched age). In contrast, divergence and isolated saccades showed only mild latency increase relative to normals. Lengthening of latency could be due to impaired cortical control. Orthoptic vergence training reduced all latencies; however, even the reduced latency of vergence and of combined movements was still abnormal. The improvement after orthoptic vergence training could be due to increased visual attention, although such mechanism cannot eliminate completely the initiation deficit of vergence movements. Objective eye movement recordings are thus useful for a diagnosis and treatment of children with vertigo.

Binocular function in school children with reading difficulties

“…This has been suggested by Kapoula et al [15]. Although there are no data to support this proposal, it has been observed that orthoptic training may improve some oculomotor abnormalities in children with vertigo [49,50]. Future work should include well-conducted studies in poor-reading children designed to assess the impacts of visual therapy on reading tasks.…”

Evidence for frequent divergence impairment in French dyslexic children: deficit of convergence relaxation or of divergence per se?

“…Such studies will help to clarify the extent to which the results from simple orthoptic tests, such as those presented here, could be used to decide whether to undertake vergence re-education. In other studies [1,2] we have shown that deficiency of vergence in orthoptic clinic tests is corroborated by eye movement studies showing abnormalities in latencies, accuracy and speed of such eye movements, as well as poor binocular coordination of saccades at near distance (M.P. Bucci, Z. Kapoula, D. Brémond-Gignac, manuscript in review); moreover, such vergence deficits are associated with headaches and balance disorders.…”

“…Asterisks indicate a significant difference between dyslexics and non-dyslexics There is a need in this field to conduct research combining orthoptic tests, visual training and recordings of eye movements during reading before and after orthoptic training. The only evidence on this issue is our studies on children with vertigo [1,2], where we showed that orthoptic training could improve some oculomotor abnormalities. Such studies are needed for dyslexics.…”

Dorsolateral Prefrontal Cortex Prevents Short-latency Saccade and Vergence: a TMS Study

“…Prior findings have shown that saccade and vergence latencies depend upon the spatial arrangement of stimuli. Yang et al (2002) and Bucci et al (2004) showed shorter latencies for movements initiated from near (20 cm; saccades or divergence) than for movements initiated from far (150 cm; saccades or convergence). Shorter mean latencies at near might be due to higher rates of express latencies, but this was not investigated.…”