Vestibular Migraine of Childhood and Recurrent Vertigo of Childhood: Diagnostic criteria Consensus document of the Committee for the Classification of Vestibular Disorders of the Bárány Society and the International Headache Society

This paper describes the diagnostic criteria for “Vestibular Migraine of Childhood”, “probable Vestibular Migraine of Childhood” and “Recurrent Vertigo of Childhood” as put forth by the Committee for the Classification of Vestibular Disorders of the Bárány Society (ICVD) and the Migraine Classification subgroup of the International Headache Society. Migraine plays an important role in some subgroups of children with recurrent vertigo. In this classification paper a spectrum of three disorders is described in which the migraine component varies from definite to possibly absent. These three disorders are: Vestibular Migraine of Childhood, probable Vestibular Migraine of Childhood and Recurrent Vertigo of Childhood. The criteria for Vestibular Migraine of Childhood (VMC) include (A) at least five episodes with vestibular symptoms of moderate or severe intensity, lasting between five minutes and 72 hours, (B) a current or past history of migraine with or without aura, and (C) at least half of episodes are associated with at least one migraine feature. Probable Vestibular Migraine of Childhood (probable VMC) is considered when at least three episodes with vestibular symptoms of moderate or severe intensity, lasting between five minutes and 72 hours, are accompanied by at least criterion B or C from the VMC criteria. Recurrent Vertigo of Childhood (RVC) is diagnosed in case of at least three episodes with vestibular symptoms of moderate or severe intensity, lasting between 1 minute and 72 hours, and none of the criteria B and C for VMC are applicable. For all disorders, the age of the individual needs to be below 18 years old. It is recommended that future research should particularly focus on RVC, in order to investigate and identify possible subtypes and its links or its absence thereof with migraine.

Visual searching capabilities in Age-Related Macular Degeneration (AMD) subjects

A decrease in visual perception with age was observed due to a decline in neurocognitive and visual functions. Previous studies showed that aging affects visual processes and contextual perceptual phenomena. The aim of our study was to explore the effect of age as well as the effect of Age-Related Macular Degeneration (AMD) on the visual searching task. Three groups of twenty-one subjects were recruited: AMD subjects (mean age 72.29 ± 4.83 years); healthy elderly (72.55 ± 4.95); and young healthy volunteers (28.38 ± 2.77). Visual perception functions were evaluated with a modified barrage test developed by Metrisquare. Our results showed that AMD patients and elderly do not differ in terms of time, omissions and errors. However both were slower to perform the visual perception tests when compared with young adults. Regarding the number of errors and omissions, we only found significant differences between the young and the AMD subjects, the later making more omissions and errors respect to young healthy volunteers. Despite AMD patients made more errors likely because to their poor fixation capability, we could conclude that AMD patients, as well as healthy elderly subjects, could compensate their altered visual strategies by taking more time to perform the visual searching tasks, probably due to cortical plasticity.HighlightsAMD patients and healthy elderly subjects do not differ in terms of time, omissions and errors.AMD patients, as well as healthy elderly subjects could compensate their visual difficulties by taking more time to perform the visual searching tasks when compared to young healthy volunteers. It is probably due to cortical plasticity.Note, however that AMD patients could make more errors when compared to young healthy volunteers, probably due to their poor fixation capability.The number of omissions and errors not different in healthy young and in elderly subjects.

Postural Instability in Subjects With Usher Syndrome

This study investigated postural performances and vestibular impairment in Usher patients. The three groups studied were: 11 patients with Usher type I (with visual and vestibular impairment), 14 patients with Usher type II (with only visual impairment), and 14 healthy control subjects. Postural stability was measured with a Framiral Multitest Equilibre platform with three visual conditions: eyes open (EO), eyes closed (EC), and vision disturbed by optokinetic stimulation (OPT), and two different postural conditions: stable or unstable platform. The surface and mean velocity of the center of pressure displacement (CoP) were measured and a postural instability index (PII) was calculated. Usher type I and II patients were more unstable than control subjects, but only for the unstable platform. Patients with Usher type I (with severe vestibular impairment) were also significantly more unstable than patients with Usher type II (with normal vestibular function) on the unstable platform. The severity of the vestibular impairment was correlated with the surface of the CoP displacement. We suggest that poor postural control of Usher patients is due to the abnormalities in their visual and, when defective, vestibular inputs. Measurements of postural stability on an unstable platform can distinguish type I from type II Usher patients. We emphasize the importance of multisensory evaluation in these patients to guide development of personalized visuo-vestibular rehabilitation techniques to improve their postural stability and improve their quality of life.

Changes of spatial and temporal characteristics of dynamic postural control in children with typical neurodevelopment with age: Results of a multicenter pediatric study

BACKGROUND

The aim of this multicenter study is to investigate the effect of chronological age and gender in postural control.

METHODS

To approach an ecological model, we used a multicenter posturography assessment. We analyzed postural control with surface, mean velocity of center of pressure [CoP] and temporal analysis, with Postural Instability Index [PII] being a more sensitive parameter in postural evaluation. A large sample of 156 age- and gender-matched healthy children recruited in several pediatrics hospitals, participated.

RESULTS

Our current results showed a significant decrease of all postural parameters (surface, mean velocity of CoP and PII) with age, and only on stable support condition. Our study additionally described a gender effect in conditions where all sensory inputs are most challenged with a mean velocity of CoP being significantly smaller in girls with respect to boys.

CONCLUSION

We concluded that postural control improves with age linked with maturation process. Moreover, this maturation process seems not yet achieved at 16.08 years and still ongoing beyond. Interestingly, our result reported specificities linked with gender effect. Indeed, girls and boys do not proceed in the same way to maintain their postural control. We could make hypothesis that more children maintain their postural control efficiently; with a low energy cost, the more they could allocate attention to learning during childhood.

Reduced Balance Restoration Capacities Following Unilateral Vestibular Insult in Elderly Mice

Acute vestibular syndrome (AVS) is characterized by severe posturo-locomotor and vestibulo-oculomotor impairment and accompanies several types of peripheral vestibulopathies (PVP). We know very little about its etiology, how its various symptoms are expressed and how it evolves with age. Robust repair capabilities of primary vestibular synapses have recently been shown to restore behavioral functionality. In this study, we used a mouse model of an excitotoxically induced unilateral vestibular lesion to compare the ability to restore balance and posture between old and young adult mice. We compared the temporal evolution of the evoked vestibular syndrome using a battery of behavioral tests to follow the evolution of postural-locomotor alterations and equilibrium. For the first time, we show that young adult (3 months) and elderly (22 months) mice are together able to restore normal postural-locomotor function following transient unilateral excitotoxic vestibular insult, though with different time courses. This animal study paves way for future, more detailed studies of how the early postural and locomotor disturbances following a unilateral insult are compensated for by various plasticity mechanisms, and in particular how age influences these mechanisms.

Developmental study identifies the ages at which the processes involved in the perception of verticality and in postural stability occur

AIM

The aim of this study was to understand the role played by visual information on the development of verticality and postural stability in healthy children.

METHODS

The study comprised 66 healthy children from 4.0 to 15.7 years of age. Postural performances were recorded with a TechnoConcept platform. At the same time, the children's perception of subjective visual vertical (SVV) was recorded while they adjusted a vertical fluorescent line, either in the dark or in the presence of perturbing visual stimuli. Two testing control conditions without an SVV task were also performed by all of the children: static posturographic recording with open eyes and closed eyes.

RESULTS

Postural measurements provided evidence of a correlation between the children's age and the tasks performed. Postural stability improved with age until eight to nine years, and SVV performance improved after 10-11 years. After these ages, postural and SVV capabilities did not change until at least 15 years of age.

CONCLUSION

Our findings suggest that the maturation of cortical and central processes involved in both the perception of verticality and in postural stability took place during childhood. However, maturation occurred later for vertical perception, which could imply delayed maturation of sensory integration processes.

Vestibular Disorders in Children With Congenital Cytomegalovirus Infection

BACKGROUND

Congenital cytomegalovirus (CMV) infection is the leading infectious cause of neurologic disabilities and sensorineural hearing loss in children. Sensorineural hearing loss prevalence in CMV suggests a viral tropism for the inner ear. Vestibular disorders induced by CMV infection are underestimated. This is the largest and most thorough study to assess the incidence of vestibular disorders and their correlation with hearing thresholds in children with CMV.

METHODS

This retrospective study assessed a cohort of 52 children with congenital CMV infection and sensorineural impairment who received a complete hearing and vestibular assessment. Vestibular evaluation included clinical examination, caloric bithermal test, earth vertical axis rotation, off-vertical axis rotation, and vestibular evoked myogenic potential. The prevalence, progression, and clinical impact of vestibular disorders were studied and correlated with hearing thresholds and the severity of congenital CMV infection.

RESULTS

Forty-eight children (92.3%) had hearing loss and vestibular disorders. Of those, vestibular disorders were complete and bilateral in 33.3%, partial and bilateral in 43.7%, and partial and unilateral in 22.9%. Serial testing in 14 children showed stable vestibular function in 50% and deterioration in 50%. Congenital CMV infection has a negative impact on postural development that is correlated with neurologic and vestibular impairment. Vestibular disorders were significantly associated with hearing disorders, but their respective severities showed no concordance.

CONCLUSIONS

Vestibular disorders are frequent and severe in CMV-infected children. Routine screening and appropriate management of vestibular lesions is essential to initiate adapted care.

Subjective visual vertical and postural capability in children born prematurely

Purpose

We compared postural stability and subjective visual vertical performance in a group of very preterm-born children aged 3-4 years and in a group of age-matched full-term children.

Materials and Methods

A platform (from TechnoConcept) was used to measure postural control in children. Perception of subjective visual vertical was also recorded with posture while the child had to adjust the vertical in the dark or with visual perturbation. Two other conditions (control conditions) were also recorded while the child was on the platform: for a fixation of the vertical bar, and in eyes closed condition.

Results

Postural performance was poor in preterm-born children compared to that of age-matched full-term children: the surface area, the length in medio-lateral direction and the mean speed of the center of pressure (CoP) were significantly larger in the preterm-born children group (p < 0.04, p < 0.01, and p < 0.04, respectively). Dual task in both groups of children significantly affected postural control. The subjective visual vertical (SVV) values were more variable and less precise in preterm-born children.

Discussion-Conclusions

We suggest that poor postural control as well as perception of verticality observed in preterm-born children could be due to immaturity of the cortical processes involved in the motor control and in the treatment of perception and orientation of verticality.

Spatial and temporal postural analysis: a developmental study in healthy children

The aim of this study was to explore further the development of postural control in healthy children. The novelty of this study was to resort to both spatial and temporal analysis of the center of pressure (CoP). Forty-six healthy children from 4 to 16 years old (mean age: 9.1±3 years) and a group of 13 healthy adults (mean age: 25±3 years) participated to this study. Postural control was tested on both a stable and an unstable platform in three different visual conditions: eyes open fixating a target, under optocinetic stimulation, and eyes closed. Resul*ts showed a significant decrease of both surface area as well as mean velocity of the center of pressure (CoP) during childhood. With the children's increasing age, the spectral power indices decreased significantly and the canceling time increased significantly. Such improvement in postural control could be due to a better use of sensorial inputs and cerebellar integration during development, allowing subjects to achieve more efficient postural control.

Postural control in strabismic children: importance of proprioceptive information

OBJECTIVE

To examine the effect of proprioceptive information during postural control in strabismic children.

METHODS

Postural stability was recorded with a platform (Techno Concept®) in 12 strabismic children aged from 4.9 to 10 years and data were compared to that of 12 control age-matched children. Two postural positions were performed: Romberg and Tandem. Two postural conditions: without and with foam pad. We analyzed the surface area, the length, the mean speed of the center of pressure (CoP) and the effect of proprioceptive information.

RESULTS

Strabismic children are more instable than control age-matched children. The surface, the length and the mean speed of CoP are significantly higher in strabismic children than in control age-matched children. Both groups are more instable in Tandem position than in Romberg position. Finally, strabismic children use more proprioceptive information than control age-matched children.

CONCLUSION

For both Romberg and Tandem position, strabismic children are more instable than control age-matched children. Strabismic children use proprioceptive information more than control age-matched children to control their posture.

SIGNIFICANCE

Proprioceptive inputs are important for control posture particularly for strabismic population.

Smooth pursuit eye movements in children with strabismus and in children with vergence deficits

Purpose

The objective of our study was to examine horizontal smooth pursuit performance in strabismic children and in children with vergence deficits, and to compare these data with those recorded in a group of control age-matched children.

Methods

Binocular eye movements were recorded by video-oculography in ten strabismic children (mean age: 9.8±0.8) and seven children with vergence deficits (mean age: 10.8±0.6). Data were compared to that of age-matched control children (mean age: 9.8±0.8 years).

Results

Catch-up saccades amplitude in strabismic children and in children with vergence deficits were significantly higher than in control age-matched children. Moreover, in strabismic children the amplitude of catch-up saccades was significantly higher in rightward than in leftward direction. The number of catch-up saccades was also significantly higher in rightward than in leftward direction. The gain value of pursuits in rightward direction was significantly higher in the right eye than in the left one; for the right eye, the gain value was significantly higher in rightward than in leftward direction. Binocular coordination of pursuit was better in control age-matched children than in children with vergence deficits and than in strabismic children.

Conclusions

Binocular coordination of pursuit is abnormal in children with vergence deficits and worse in strabismic children. Binocular vision plays an important role in improving binocular coordination of pursuit.

Saccades improve postural control: a developmental study in normal children

INTRODUCTION

Dual-task performance is known to affect postural stability in children. This study focused on the effect of oculomotor tasks like saccadic eye movements on postural stability, studied in a large population of children by recording simultaneously their eye movements and posture.

MATERIALS AND METHODS

Ninety-five healthy children from 5.8 to 17.6 years old were examined. All children were free of any vestibular, neurological, ophtalmologic and orthoptic abnormalities. Postural control was measured with a force platform TechnoConcept®, and eye movements with video oculography (MobilEBT®). Children performed two oculomotor tasks: fixation of a stable central target and horizontal saccades. We measured the saccade latency and the number of saccades during fixation as well as the surface, length and mean velocity of the center of pressure.

RESULTS

During postural measurement, we observed a correlation between the age on the one hand and a decrease in saccade latency as well as an improvement in the quality of fixation on the other. Postural sway decreases with age and is reduced in the dual task (saccades) in comparison with a simple task of fixation.

DISCUSSION - CONCLUSION

These results suggest a maturation of neural circuits controlling posture and eye movements during childhood. This study also shows the presence of an interaction between the oculomotor system and the postural system. Engaging in oculomotor tasks results in a reduction of postural sway.

Subjective visual vertical and postural performance in healthy children

Introduction

Verticality is essential in our life, especially for postural stability. Subjective vertical as well as postural stability depends on different sensorial information: visual, vestibular and somesthesic. They help to build the spatial referentials and create a central representation of verticality. Children are more visuo-dependant than adults; however, we did not find any study focusing on how children develop their sense of verticality.

Methods

We studied two groups of subjects: 10 children (from 6 to 8 years) and 12 young adults. We recorded postural stability with a Techno Concept plateform and perception of subjective visual vertical in the following conditions: while adjusting the vertical in the dark or with visual perturbation, while fixating the vertical bar, and with eyes closed.

Results

Children are more instable than adults in terms of postural parameters, and also while performing a double task, especially when no visual references are present. They also present a higher variability and lower accuracy than adults in reporting their perception of true vertical reference.

Discussion

Children might have limited attentional resources, and focus their attention on the more demanding task, corresponding to the U-shaped non-linear model.

Binocular coordination of saccades during reading in children with clinically assessed poor vergence capabilities

Prior studies have pointed toward a link between the saccadic and vergence systems, coordinating binocular saccadic movements. Recent studies have shown that vergence deficits in children induce poor binocular coordination during saccades, but none of them have studied ocular motility in children during a daily task such as reading. The present study tests whether vergence deficits in children perturb binocular coordination of saccades and fixation during reading. Our second objective was to explore whether vergence training could improve the quality of binocular coordination. Twelve patients (from 7.3 to 13.4 years old) complaining from vertigo but without vestibular and neurological pathology underwent orthoptic tests and were selected for our study when they presented vergence deficits. Eye movements were recorded during a reading task with a Mobile EyeBrain® Tracker video-oculography system. Data were compared to twelve age-matched controls with normal orthoptic values. While there was no statistically significant difference in saccade amplitudes between the two groups (p=0.29), patients showed higher disconjugacy during and after the saccades compared to controls (p<0.001). After orthoptic training, six patients out of the first 12 examined came back for a second oculomotor test. All showed a significant improvement of their binocular saccade coordination. We suggest that the larger disconjugacy during reading observed in patients before training could be due to poor vergence as initially assessed by orthoptic examination. Such findings support the hypothesis of a tight relationship between the saccadic and vergence systems for controlling the binocular coordination of saccades. The improvement reported after orthoptic training is in line with the hypothesis of an adaptative interaction on a premotor level between the saccadic and vergence system.

Changes in vergence dynamics due to repetition

Vergence insufficiency is frequent in many populations including children with vertigo in the absence of measurable vestibular dysfunction. Orthoptic exercises are typically used to improve vergence and the clinical practice suggests that simple repetition of vergence movements improves it. Objective eye movement recordings were used to asses the dynamics and spatial-temporal properties of convergence (8.7°) and divergence (2.7°) along the midline while these movements were repeated 80 times. Eight children, aged on average 13years and showing vertigo symptoms accompanied with vergence insufficiency, participated. For both, convergence and divergence the velocity increased and the overall duration decreased; the amplitude of the mean transient component of the response changed significantly. These findings are compatible with models of double mode control of vergence eye movements (transient - open-loop vs. sustained - closed loop). Due to simple repetitions a real improvement in the dynamics of vergence along the midline occurred.

Potential value of vestibular evoked myogenic potentials in paediatric neuropathies

Purpose: Showing the interest of vestibular evoked myogenic potentials in paediatric neurological vestibulospinal pathology detection and followup. Materials and methods: The vestibular evoked myogenic potentials testing apparatus presented is now commonly used in ENT clinics for patients from 1 month of age. Our system and protocol permits control to evoke and select the best EMG level and makes possible a comparison of data from different sides or level of stimulation or different sessions. Normal vestibular evoked myogenic potentials latencies obtained with tone bursts were remarkably stable (P: 13 +/− 0.8 ms, N: 19.6 +/− 1.6 ms). The reported case illustrates abnormal vestibular evoked myogenic potentials latencies in neuropathy. Results: A 6 y.o. child with progressive imbalance was referred to the ENT department for vestibular functional evaluation. Abnormally long latencies in the vestibular evoked myogenic potentials and neurological examination oriented the diagnosis towards Guillain-Barre syndrome and immediate referral to a neurology department. Vestibular evoked myogenic potentials also helped to monitor the neurological recovery. Conclusion: The present case shows the potential value of vestibular evoked myogenic potentials in diagnosis and evaluation of descending brainstem pathways in neuropathies like Guillain-Barre syndrome in complement to neurological evaluation.

[Vestibular neuronitis in a teenager with sickle cell disease. Treatment is urgent]

Vestibular syndrome is not frequently described in patients with sickle cell disease. We report the case of a teenager with sickle cell disease who had a vestibular syndrome with vertigo that successfully responded to exchange transfusion. We discuss guidelines and review the literature in view of this case report. Sensorineural disorders should be considered as stroke syndromes. They require urgent treatment consisting of exchange transfusion or maintaining optimal hydration associated with blood withdrawal. Treatment of vestibular syndrome in sickle cell disease is urgent.

Potential value of vestibular evoked myogenic potentials in paediatric neuropathies

PURPOSE

Showing the interest of vestibular evoked myogenic potentials in paediatric neurological vestibulospinal pathology detection and followup.

MATERIALS AND METHODS

The vestibular evoked myogenic potentials testing apparatus presented is now commonly used in ENT clinics for patients from 1 month of age. Our system and protocol permits control to evoke and select the best EMG level and makes possible a comparison of data from different sides or level of stimulation or different sessions. Normal vestibular evoked myogenic potentials latencies obtained with tone bursts were remarkably stable (P: 13 +/- 0.8 ms, N: 19.6 +/- 1.6 ms). The reported case illustrates abnormal vestibular evoked myogenic potentials latencies in neuropathy.

RESULTS

A 6 y.o. child with progressive imbalance was referred to the ENT department for vestibular functional evaluation. Abnormally long latencies in the vestibular evoked myogenic potentials and neurological examination oriented the diagnosis towards Guillain-Barre syndrome and immediate referral to a neurology department. Vestibular evoked myogenic potentials also helped to monitor the neurological recovery.

CONCLUSION

The present case shows the potential value of vestibular evoked myogenic potentials in diagnosis and evaluation of descending brainstem pathways in neuropathies like Guillain-Barre syndrome in complement to neurological evaluation.

Familial CHARGE syndrome because ofCHD7mutation: clinical intra- and interfamilial variability

CHARGE syndrome (OMIM #214800) is a multiple malformation syndrome with distinctive diagnostic criteria, usually because of CHD7 (chromodomain helicase DNA binding 7) haploinsufficiency. Familial occurrence of CHARGE syndrome is rare. We report six patients from two Caucasian families (both with one parent and two children) affected by mild to severe CHARGE syndrome. Direct sequencing of the CHD7 gene was performed in these two unrelated families. A mutation in exon 8 (c.2501C>T - p.S834F) in first chromodomain was found in family A and a nonsense mutation in exon 2 (c.469C>T - p.R157X) in family B. Both mutations are de novo in the parents. In family A, the elder son had bilateral cleft lip and palate, esophageal atresia with fistula, complex heart defect and vertebral abnormalities, while the younger had a posterior coloboma. Their mother had asymptomatic vestibular dysfunction and retinal coloboma, identified after the molecular diagnosis of her children. In family B, both affected children had severe expression of CHARGE syndrome. The father carrying the mutation only had asymmetric anomaly of the pinnae. These familial reports describe the intrafamilial variability of CHARGE syndrome, and underline the presence of CHD7 mutations in patients who do not fit the 'classical clinical criteria' for CHARGE syndrome.

Evaluation of vertiginous children

Our objective was to evaluate, using a structured approach method, the history and findings in vertiginous children as compared with a group of healthy children. We evaluated 24 vertiginous children (15 girls, 9 boys) with episodes of true vertigo of unknown etiology and 12 healthy age- and gender-matched controls. A detailed medical history was obtained using a structured approach technique. Vertiginous and healthy children underwent general and otoneurologic examinations, including audiogram, electronystagmography, and tympanometry, at the Helsinki University Hospital ENT clinic. Characteristics of patient histories and clinical findings were compared between the groups. The vertiginous children reported significantly more head traumas and headaches than the controls. The structured data collection approach improved the evaluation process. The predominant diagnoses were benign paroxysmal vertigo of childhood, otitis media-related vertigo, and migraine-associated dizziness.

Binocular coordination of saccades in children with vertigo: dependency on the vergence state

The present study examines the quality of binocular coordination of saccades at far and near distance in 15 children with symptoms of vertigo headache and equilibrium disorders; these children show normal vestibular function but abnormal convergence eye movements (e.g., long time preparation, slow execution and poor accuracy, see ). The results show normal binocular saccade coordination at far distance, but large abnormal disconjugacy for saccades at near distance. During combined saccade-vergence movements (studied in six of these children), convergence remains abnormally slow. This supports the interpretation according to which poor binocular yoking of the saccades is linked to the reduced ability to produce fast convergence during the saccade; a learning mechanism based on rapid vergence would help to reduce the abducting-adducting asymmetry of the saccades. An alternative interpretation would be reduced learning ability for monocular adjustment of the saccade signals.

Speed-accuracy of saccades, vergence and combined eye movements in children with vertigo

Vergence abnormalities could lead to inappropriate vestibulo-ocular reflex (VOR), causing vertigo and imbalance (Brandt 1999). Indeed, a recent study by Anoh-Tanon et al. (2000) reported the existence of a population of children with symptoms of vertigo in the absence of vestibular dysfunction but with abnormal vergence findings in orthoptic tests. The purpose of this study was to examine in such children the accuracy, duration and mean velocity of vergence and saccades; additionally, for a few subjects, the effect of orthoptic vergence training on these parameters was also investigated. LEDs were used to stimulate saccades, pure vergence along the median plane and combined saccade-vergence movements. Movements from both eyes were recorded with a photoelectric device (Bouis). The results show that children with vertigo perform saccades as normal subjects of comparable age. In contrast, vergence, particularly convergence, shows abnormalities: poor accuracy, long duration and low speed. During combined movements, the well known reciprocal interaction between the saccade and the vergence is present only for saccades combined with divergence; for saccades combined with convergence such interaction is abnormal: the saccade is slowed down by the convergence but the convergence is not accelerated by the saccade. Orthoptic training improves significantly the accuracy of all eye movements; such improvement was significant for all types of eye movements except for divergence (pure and combined). Furthermore, convergence remains abnormal and the lack of acceleration by the saccade persists. These specific convergence deficits could be of both subcortical and cortical origin. Orthoptic training improves the accuracy presumably via visual attentional mechanisms, but cannot completely override deficits related to subcortical deficiencies.

Abnormality of vergence latency in children with vertigo

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.

Saccades, vergence and combined eye movements in a young subject with Congenital Central Hypoventilation Syndrome (CCHS)

PURPOSE

To study saccades, vergence and combined eye movements in a case of Congenital Central Hypoventilation Syndrome.

METHODS

A 16-year-old girl with congenital partial third cranial nerve palsy, with ptosis and divergent strabismus dependent on viewing distance, participated in this study. A first operation for her ptosis was done seven years ago and an operation for her strabismus was done four years ago. The day of our oculomotor test, the patient had a residual exotropia of 12 prism diopters, mild amblyopia of the left eye and no binocular vision. LEDs on a table placed at eye level were used to stimulate saccades, pure vergence along the median plane and combined saccade-vergence movements. Horizontal eye movements from both eyes were recorded simultaneously with a photoelectric device (Bouis Oculometer).

RESULTS

The binocular coordination of saccades in this subject was unstable and more variable than normal, and there was divergent post-saccadic drift, i.e., in the direction of her residual deviation. The patient had difficulty making movements in space, particularly vergence eye movements. Pure saccades and combined movements showed abnormally long latencies and marked hypometrias. The velocity of pure saccades was normal. In contrast, the velocity of saccades in the combined movements was abnormally slow.

CONCLUSION

The long latency and the low accuracy of the eye movements in natural space indicate a general deficit in the central circuitry that controls the initiation and programming of all these types of eye movements. The absence of pure vergence and the slowness of the saccades in the combined movements could be due to a brainstem deficit specific to the vergence oculomotor system.

Vestibular anomalies in CHARGE syndrome: investigations on and consequences for postural development

Recently, vestibular anomalies have been described as a frequent feature in children with coloboma-heart-atresia-retarded-genital-ear (CHARGE) syndrome. They are likely to play an important role in the psychomotor retardation affecting these children. In order to test this hypothesis, we prospectively performed complete vestibular investigations in a series of 17 CHARGE syndrome patients including inner ear CT scan and functional vestibular evaluation of both canal and otolith functions. These results were correlated with the postural anomalies observed during the children's development and showed that vestibular dysfunction is a constant feature in CHARGE syndrome and has very good sensitivity for confirming the diagnosis. Anomalies of semicircular canals were frequently found (94%), easily detectable on CT scan and associated with no response on canal function evaluation. They were considered as partly responsible for the retardation of postural stages. Vestibular functional tests were consistently abnormal but allowed detection of residual otolith function in most patients (94%). All children of this series had an atypical pattern of postural behaviour that we consider to be related to their vestibular anomalies. Residual otolith function seems to have a positive influence for postural development.

CONCLUSION

Vestibular investigations are valuable for diagnosis, developmental assessment, and adaptation of specific rehabilitation programmes in CHARGE syndrome patients.

[Inner ear in C.H.A.R.G.E. association]

Cochleovestibular dysfunction is one of the major features of C.H.A. R.G.E. association. The inner ear anomalies were studied in a population of 17 children with CHARGE. Temporal bone anomalies were defined with CT scan, hearing loss was evaluated with audiologic procedures appropriate for age, and functional canal and otolith vestibular impairment evaluated with respectively vertical and off vertical axis rotation (OVAR) tests. Temporal bone anomalies appear specific of C.H.A.R.G.E. association. They are characterized by an aplasia of the posterior labyrinth (with an absence of semicircular canals) and a variable degree of anomalies of the anterior labyrinth with sometimes normal cochlea. Hearing loss is variable, often worsened by delayed neurological maturity and frequent association of middle ear effusion. Thus, multiple audiologic evaluations are required at regular intervals. The treatment of middle ear effusion, the association of hearing aid and speech therapy management permit language acquisition in spite of the other multiple sensory handicaps. Vestibular functional evaluation shows a constant canal areflexia but a residual vestibular otolith function (sometimes normal). The deficit of the vestibular function is certainly involved in the delay of posturo-motor development as well as visual deficit and neurological impairment. This can permit an adaption of the physical therapy program for each child to make use of the available sensorial information.

[Direct foreign body footplate trauma: 3 cases]

3 cases of direct foreign body footplate trauma are described in children. A surgical exploration was decided on history, cochleovestibular signs and/or CT abnormalities. Hearing improved in all cases after surgery.

Head coordination in the sagittal plane in toddlers during walking: preliminary results

In adults, head rotations in the pitch plane are highly synchronized with vertical head translations during different locomotor tasks as walking, running, and hopping. The head is rotating up then down in the pitch plane as stepping movement drives the head down then up, respectively. The purpose of our study was to determine at which period of the motor control development this fine head coordination occurred. The organization of head movements was analyzed in four normal children observed longitudinally from the onset of walking up to 80 weeks of independent walking (IW). The degree of synchronization between vertical head translations and head rotations in the pitch plane was used to define an index of head coordination for 15 to 25 steps per child per session. Our results show that the coordination of head rotations in the pitch plane improves continually in toddlers but does not reach the optimal level during the first year of IW experience. We showed previously that head stabilization in space was achieved during the first weeks of IW. Both head stabilization in space and fine head coordination during walking are considered as directly involved in gaze stabilization, but in toddlers head stabilization in space is completed earlier than head coordination. Head stabilization appears to be a necessary motor control to acquire prior to the development of head movement coordination.

Trunk and head stabilization during the first months of independent walking

This study measured the rate of acquisition of head and trunk postural control during the two early developmental periods of independent walking, as defined by global gait parameters. Gait parameters were observed longitudinally in four children. The maximum angular deviations of the trunk and head oscillations were computed in the frontal and sagittal planes. These decreased most dramatically during the first 10-15 weeks of independent walking, during the same period when global gait parameters changed rapidly. This head and trunk stabilization may be a fundamental process that help to maintain equilibrium during walking, and may be a necessary step prior to the development of fine posturo-motor control.