Severe Oculomotor Research Articles

Нарушение подвижности глазного яблока у пациентов с травматическим косоглазием

Relevance. Limitation of eyeball mobility is one of the main signs of traumatic strabismus. The following main factors of its occurrence have been identified: trauma to the eye and periorbital region, orbital fracture, concussion and severe cranio-orbital or traumatic brain injury. Oculomotor function may suffer due to paresis/paralysis of the extraocular muscle, its mechanical damage or entrapment in the area of the fracture of the orbital bones (in cases where strabismus has developed as a result of an orbital fracture), or due to the formation of severe tissue fibrosis and restriction. Purpose. To study the dynamics of oculomotor function before and after surgical treatment of traumatic strabismus in patients with dystopia of the eyeball and without it. Material and methods. A retrospective analysis of outpatient records of 269 patients with traumatic strabismus was carried out. Results. Dystopia of the eyeball was detected in 34%. Exophthalmos accounts for approximately a third of all dystopias occurring in traumatic strabismus. An isolated fracture of the orbital wall did not cause exophthalmos. In such cases, other types of dystopias were noted. But in more extensive and severe injuries to the skull, exophthalmos occurred in 10% of cases. Among all cases of exophthalmos, in 40% it developed as a result of injury to the eye or periorbital region, in 60% – with severe cranio-orbital damages (COD) and head injury. It was found that as a result of surgical treatment, the number of patients with normal eyeball mobility increased from 16 to 24%. Lack of eyeball mobility was noted in 7% of patients, while before treatment their number was almost 19%. In the group without dystopia with moderate oculomotor disorders, after treatment, the mobility of the eyeball did not improve in 65% of patients; it improved in 31% of patients; in the group with dystopia, 41% retained the same degree of mobility limitation, and improvement (decrease in the degree of limitation) was detected in 55% of patients. Conclusion.It has been established that dystopia causes more severe oculomotor disorders. However, adequate surgical treatment can improve eye mobility in more than half of the patients. Key words: traumatic strabismus, dystopia, orbital rupture, eyeball mobility, restriction, fibrosis

Adolescents With More Oculomotor and Vestibular Signs of Sport-Related Concussion Benefit from Aerobic Exercise: An Exploratory Analysis.

Abstract Early targeted heart rate (HR) aerobic exercise has been shown to reduce the duration of recovery from sport-related concussion (SRC) as well as the incidence of persistent post-concussive symptoms (PPCS). It is not known, however, if more severe oculomotor and vestibular presentations of SRC benefit from a prescription of aerobic exercise. The current study is an exploratory analysis of two published randomized controlled trials that compared aerobic exercise within 10 days of injury with a placebo-like stretching intervention. Combining the two studies yielded a larger sample size to stratify severity of concussion based on the number of abnormal physical examination signs present at the initial office evaluation, which were confirmed with self-reported symptoms and recovery outcomes. The most discriminant cut-off was between those who had ≤3 oculomotor and vestibular signs and those who had >3 signs. Aerobic exercise (hazard ratio = 0.621 [0.412, 0.936], p = 0.023) reduced recovery times even when controlling for site (hazard ratio = 0.461 [0.303, 0.701], p < 0.001), severity (hazard ratio = 0.528 [0.325, 0.858], p = 0.010) and the interaction term of intervention and severity (hazard ratio = 0.972 [0.495, 1.909], p = 0.935). Adolescents who presented with >3 signs and were assigned to the placebo-like stretching group had a PPCS incidence of 38%, which was the highest of all subgroups (aerobic exercise and ≤3 findings: 8%; stretching and ≤3 findings: 11%; aerobic exercise and >3 findings: 21%). This exploratory study provides pilot evidence that prescribed sub-symptom threshold aerobic exercise treatment early after SRC may be effective for adolescents with more oculomotor and vestibular physical examination signs and should be validated in future adequately powered trials.

Orbital Intravascular Natural Killer/T-cell Lymphoma: An Unusual Cause of Ocular Symptoms

Orbital intravascular lymphoma is rare and typically of B-cell lineage. In this study, we report a patient who developed orbital lesions of intravascular natural killer/T-cell lymphoma (IVNKL), an extremely rare lymphoma. An 88-year-old man presented with rapidly progressive right vision loss and double vision. A neurological examination revealed that he had decreased visual acuity and severe oculomotor impairment in the right eye. Magnetic resonance imaging showed right-dominant, nonmass lesions in both orbits. No lesions were found in the lymph nodes, skin, or brain. The patient received immunosuppressive and antifungal therapy, but his clinical condition rapidly deteriorated, and he died of multiple organ failure. Autopsy revealed natural killer/T-cell lymphoma proliferation within the lumina of small blood vessels in multiple organs, including the ocular adnexa of the right orbit. These findings show that he was ultimately diagnosed with IVNKL. IVNKL could initially cause ocular symptoms due to the involvement of the ocular adnexa. Ocular involvements have not been described previously. Even if patients initially present with only ocular symptoms, IVNKL should be considered.

Clinical Characteristics for Predicting Recovery of Acquired Fourth Cranial Nerve Palsy.

Fourth cranial nerve palsy is the most common disease diagnosed in patients with vertical diplopia. Although it is reported to present a good prognosis, there are currently no agreed on prognostic factors that anticipate the recovery of the palsy other than the etiology. The purpose of this study was to investigate the prognostic factors of acquired fourth cranial nerve palsy. The medical records of consecutive patients diagnosed with acquired unilateral fourth cranial nerve palsy from 2010 to 2020 and followed up for ≥6 months were retrospectively reviewed. The cause and degree of palsy, ocular deviation (horizontal, vertical, and cyclo), and fundus torsion were reviewed. The cause of palsy was classified as ischemic, traumatic, intracranial mass, others, or idiopathic. Patients were divided into 2 groups according to palsy recovery: complete recovery (group CR) or not CR (group NCR). The clinical characteristics of the 2 groups were compared, and the risk factors for incomplete recovery were investigated. Thirty-five patients (25 men) were included in the study. The average age was 55.94 ± 16.11 years. CR was achieved in 23 patients (65.7%), and the time to recovery was 3.91 ± 4.03 months. The most common cause was traumatic (40.0%), followed by ischemia (37.1%), intracranial mass (11.4%), others (8.6%), and idiopathic (2.9%). The degree of palsy and fundus torsion was significantly higher in group NCR (P = 0.010 and P = 0.001). Severe oculomotor limitation, large fundus torsion, and intracranial mass cause rather than ischemic cause indicated a higher risk of incomplete or no recovery (P = 0.016, P = 0.009, and P = 0.043). Identifying whether a patient has an intracranial mass, severe oculomotor limitation, or large fundus excyclotorsion may be useful for predicting the recovery of acquired unilateral fourth cranial nerve palsy.

Oculomotor Deficits after Chemotherapy in Childhood.

Advances in the diagnosis and treatment of pediatric malignancies have substantially increased the number of childhood cancer survivors. However, reports suggest that some of the chemotherapy agents used for treatment can cross the blood brain barrier which may lead to a host of neurological symptoms including oculomotor dysfunction. Whether chemotherapy at young age causes oculomotor dysfunction later in life is unknown. Oculomotor performance was assessed with traditional and novel methods in 23 adults (mean age 25.3 years, treatment age 10.2 years) treated with chemotherapy for a solid malignant tumor not affecting the central nervous system. Their results were compared to those from 25 healthy, age-matched controls (mean age 25.1 years). Correlation analysis was performed between the subjective symptoms reported by the chemotherapy treated subjects (CTS) and oculomotor performance. In CTS, the temporal control of the smooth pursuit velocity (velocity accuracy) was markedly poorer (p<0.001) and the saccades had disproportionally shorter amplitude than normal for the associated saccade peak velocity (main sequence) (p = 0.004), whereas smooth pursuit and saccade onset times were shorter (p = 0.004) in CTS compared with controls. The CTS treated before 12 years of age manifested more severe oculomotor deficits. CTS frequently reported subjective symptoms of visual disturbances (70%), unsteadiness, light-headedness and that things around them were spinning or moving (87%). Several subjective symptoms were significantly related to deficits in oculomotor performance. To conclude, chemotherapy in childhood or adolescence can result in severe oculomotor dysfunctions in adulthood. The revealed oculomotor dysfunctions were significantly related to the subjects’ self-perception of visual disturbances, dizziness, light-headedness and sensing unsteadiness. Assessments of oculomotor function may, thus, offer an objective method to track and rate the level of neurological complications following chemotherapy.

Clinical Implications of the Center of Balance for a Veteran with Traumatic Brain Injury

Background: It is known that traumatic brain injury (TBI), even of the mild variety, can cause diffuse multisystem neurological damage. Coordination of sensory input from the visual, vestibular and somatosensory pathways is important to obtain proper balance and stabilization in the visual environment. This coordination of systems is potentially disrupted in TBI leading to visual symptoms and complaints of dizziness and imbalance. The Center of Balance (COB) at the Northport Veterans Affairs Medical Center (VAMC) is an interprofessional clinic specifically designed for patients with such complaints. An evaluation entails examination by an optometrist, audiologist and physical therapist and is concluded with a comprehensive rehabilitative treatment plan. The clinical construct will be described and a case report will be presented to demonstrate this unique model. Case Report: A combat veteran with a history of a gunshot wound to the skull, blunt force head trauma and exposure to multiple explosions presented with complaints of difficulty reading and recent onset dizziness. After thorough evaluation in the COB, the patient was diagnosed with and treated for severe oculomotor dysfunction and benign paroxysmal positional vertigo. Conclusion: Vision therapy was able to provide a successful outcome via improvement of oculomotor efficiency and control. Physical therapy intervention was able to address the benign paroxysmal positional vertigo. The specific evaluation and management as pertains to the aforementioned diagnoses, as well as the importance of an interprofessional rehabilitative approach, will be outlined.

Radiation-associated grade 2 meningiomas: A nine patient-series and review of the literature

IntroductionRadiation-associated meningiomas (RAM) remain rare but recognized to harbor a high potential of aggressiveness. Only few studies focused on grade 2 histological variants. ObjectiveOur study aims to report the natural history of patients with radiation-associated grade 2 meningiomas followed in a single institution. Materials and methodsThis retrospective study included all patients with grade 2 RAM operated in our institution between 1994 and 2011. We used the WHO 2007 classification for histological grading. The degree of resection was evaluated using Simpson Classification. The tumor was considered radiation-associated, if the patient had a medical history of cranial irradiation for another medical condition (1 year before at least). Patients benefited from a post-operative close clinical and radiological (cranial MRI) follow-up every 4 months during 2 years and annually thereafter, to detect any tumor progression. Adjuvant therapy and/or monitoring were systematically decided during a multidisciplinary team meeting. ResultsNine patients (6 men and 3 women) were included in the study. The mean age at diagnosis was 34 years old (range 20–55 years). The mean follow-up was 77 months (range 31–180 months). The mean delay between initial cranial radiation therapy and the diagnosis of grade 2 RAM was 23 years (range 16–33 years). Among all patients, 4 harbored a meningiomatosis, while 5 patients harbored a single tumor. Post-operative local tumor progression was noted in 4 patients. Progression free survival (PFS) after the first surgery in these 4 patients was 15, 23, 35, and 47 months. In these 4 progressive patients, 7 surgical resections, 3 GKS and 1 fractionated radiation therapy have been performed. Post-operative tumor progression was noted at distance from the operated meningioma in 1 patient with meningiomatosis. At final control, 2 patients had severe oculomotor palsy and 1 patient needed palliative cares related to progressive meningiomatosis with anorexia and swallowing disturbance. ConclusionGrade 2 RAM is a severe radiation-associated disease occurring preferentially in younger male patients. Although, surgery remains the mainstay treatment, the high potential of tumor progression often requires adjuvant therapeutic tools. Thus, new radiation therapy should be discussed in some cases and the role of radio surgery is still to be better defined.

Visual Involvement in Corticobasal Syndrome

Corticobasal syndrome (CBS) is the clinical presentation of corticobasal degeneration (CBD), a rare neurodegenerative disorder, with features of both cerebral and basal ganglia involvement. Visual disturbance is uncommonly a predominant symptom but when present can be markedly debilitating. Visual findings primarily manifest as oculomotor apraxia, but significant cognitive impairment may result in the inability to process visuospatial information and can result in simultagnosia and visuomotor ataxia. A 60-year-old woman with a history of CBS presented with progressive visual impairment. Her symptoms were primarily due to severe oculomotor apraxia, optic ataxia, and pronounced simultagnosia. We present the case and review the literature regarding visual dysfunction in CBS.

Rebalancing the commissural system: Mechanisms of vestibular compensation

Vestibular compensation after unilateral vestibular loss is a complex, multi-factored process involving synaptic and neuronal plasticity in many areas of the brain, and it is a challenge to identify the key sites of plasticity that determine the rate and extent of behavioural recovery. Experimental evidence strongly implicates the vestibular commissural inhibitory system which links the brainstem vestibular nuclei of the two sides, both in causing the initial severe oculomotor and postural symptoms of vestibular deafferentation, and in the subsequent recovery that takes place in the early stages of compensation. Of particular interest are changes in GABAergic neurotransmission within the commissural system, and the possibility that histaminergic drugs as well as stress steroids and neurosteroids that can modulate compensation, may do so at least in part by their effects on commissural inhibition. A fuller understanding of the role of the commissural system in compensation and the effects of GABAergic neuromodulators is likely to reveal the mechanisms of action of histamine in the vestibular system and the interactions between stress, anxiety and vestibular dysfunction.

Role of the commissural inhibitory system in vestibular compensation in the rat

We investigated the role of the vestibular commissural inhibitory system in vestibular compensation (VC, the behavioural recovery that follows unilateral vestibular loss), using in vivo microdialysis to measure GABA levels in the bilateral medial vestibular nucleus (MVN) at various times after unilateral labyrinthectomy (UL). Immediately after UL, in close correlation with the appearance of the characteristic oculomotor and postural symptoms, there is a marked increase in GABA release in the ipsi-lesional MVN. This is not prevented by bilateral flocculectomy, indicating that it is due to hyperactivity of vestibular commissural inhibitory neurones. Over the following 96 h, as VC occurs and the behavioural symptoms ameliorate, the ipsi-lesional GABA levels return to near-normal. Contra-lesional GABA levels do not change significantly in the initial stages of VC, but decrease at late stages so that when static symptoms have abated there remains a significant difference between the MVNs of the two sides. We also investigated the role of the commissural inhibition in Bechterew's phenomenon, by reversibly inactivating the intact contra-lesional labyrinth in compensating animals through superfusion of local anaesthetic on the round window. Transient inactivation of the intact labyrinth elicited the lateralized behaviour described by Bechterew, but did not alter the GABA levels in either MVN, suggesting the involvement of distinct cellular mechanisms. These findings indicate that an imbalanced commissural inhibitory system is a root cause of the severe oculomotor and postural symptoms of unilateral vestibular loss, and that re-balancing of commissural inhibition occurs in parallel with the subsequent behavioural recovery during VC.

Cerebral visual impairment in preterm infants with periventricular leukomalacia

Neonatal brain lesions are the main cause of cerebral visual impairment in infancy, i.e., of a visual deficit caused by damage to posterior visual pathways. Visual outcome of preterm infants with periventricular leukomalacia (PVL) was investigated in 14 subjects affected by severe cystic PVL, another 34 with moderate PVL (prolonged periventricular echodensities), and 18 control preterm infants. All cases with significant ocular abnormalities (such as retinopathy of prematurity state III or upwards, optic nerve atrophy, or major refraction problems) were excluded. Visual acuity, visual field, eye alignment, fixation and following, optokinetic nystagmus, and visual threat were tested at 1 year of corrected age. A high incidence of cerebral visual impairment, consisting mainly of low visual acuity, severe oculomotor disorders, and reduced visual field, was found in infants with severe PVL. Visual defects were less frequent and less severe in the moderate PVL group, and very rare in the control group. The results of neuroimaging, and especially of magnetic resonance imaging, correlated with the visual outcome and indicate lesions at the level of optic radiations as the main anatomic substrate of the visual impairment. All infants with PVL need a visual follow-up, from the first months of life, the results of which are important both for visual and motor rehabilitation of these cases and for their daily care.

Oculomotor abnormalities and MRI findings in idiopathic cerebellar ataxia.

Extensive oculomotor testing and quantitative MRI evaluation was performed in seven patients with idiopathic cerebellar ataxia without extracerebellar symptoms (IDCA-C) and in ten patients with additional extracerebellar symptoms (IDCA-P). The most severe oculomotor deficits were disturbed smooth pursuit, optokinetic nystagmus and suppression of the vestibulo-ocular reflex (VOR). The symptoms correlated well and consistently with the amount of atrophy of the flocculus and the dorsal vermis. These correlations, however, were not specific, and deficits also correlated with the amount of atrophy of other cerebellar structures. No correlation was found between saccade velocity and brainstem atrophy or between saccade metrics and atrophy of the dorsal vermis. Although patients with IDCA-P had more severe oculomotor deficits than patients with IDCA-C, the pattern of the oculomotor disturbances was the same for both groups. Thus, eye movement analysis alone is not sufficient to distinguish between patients with pure cerebellar ataxia and those with additional extracerebellar symptoms.