PURPOSE: To develop an algorithm in order to establish a consensus on how oculomotor nerve schwannomas should be treated by reviewing results from reported cases in the literature. Given the rarity of oculomotor nerve schwannomas, there is no agreed upon criteria for when a surgical or a nonsurgical intervention would be indicated. By reviewing former cases of oculomotor nerve schwannomas, our study proposes a flowchart for physicians to follow for optimal management. METHODS: The review of reported oculomotor nerve schwannoma cases involved 51 cases. From the 51 cases, data was tabulated including age, patient symptoms, symptom duration, tumor size, tumor location, treatment, post operative results, and follow up time. The cases were then divided in to surgical subgroup and a nonsurgical subgroup. Each case was also grouped based on post operative oculomotor function into improved, no change, and worsened groups. Our collaboration with Tufts Medical center also yielded 4 unreported cases of oculomotor nerve schwannoma that are described and compared to the previous 51 cases from the literature review. RESULTS: The review of the 51 reported cases yielded a few statistically significance differences between the surgical and nonsurgical subgroups. The surgical subgroup was older with a mean age of 35 years than the nonsurgical subgroup with a mean age of 15.8 years. The surgical group also had larger tumors with a mean tumor diameter of 29.5 mm versus the nonsurgical subgroup's 4.5 mm mean tumor diameter. The surgical subgroup also experienced shorter symptom durations as well. The mean duration of symptoms in the surgical subgroup was 17.8 months versus the 140 month mean symptom duration for the nonsurgical cases. Finally, the majority of surgically treated cases experienced a worsening of residual oculomotor function (20/38), while the majority of nonsurgically treated cases experienced little to no change in oculomotor function (11/13). CONCLUSION: Given the high likelihood of complete third nerve palsy after surgery, this study advocates a conservative approach to oculomotor nerve schwannomas that do not present with any life threatening symptoms or acutely deteriorating symptoms. The cases that are presented in this study also corroborate previous studies' findings on the efficacy of stereotactic radiosurgery in managing schwannoma size without resorting to more invasive interventions.

Previous research has shown increased saccade latencies in patients with Alzheimer’s disease and mild cognitive impairment; however, this is not well-understood in patients with delirium. The present study investigates eye-tracking metrics to evaluate the feasibility of using eye-tracking to discern delirious patients from disease control patients. We recruited 24 participants from the inpatient and intensive care units (ICU) at Massachusetts General Hospital (MGH) and assessed for delirium via CAM-S, a screening tool for delirium. Participants were instructed to follow a dot stimulus as it moves across the laptop screen as their eye movements were simultaneously tracked by a Tobii Pro Fusion eye-tracker. Our experimental paradigm involved gap saccades (central fixation extinguishes before the centrifugal target appears), overlap saccades (central fixation remains after centrifugal target onset), horizontal smooth pursuit, and circular smooth pursuit tasks. The eye-tracking metrics discussed in this study are the calibration and validation accuracies, saccade latencies and total target gaze duration. Our eye-tracking method was able to capture subjects’ gaze direction and path, but further research is needed to draw strong conclusions about the feasibility to detect oculomotor abnormalities in patients with delirium.

Yes / The issue of whether visually-mediated, simple reaction time (VRT) is faster in elite athletes is contentious. Here, we examined if and how VRT is afected by gaze stability in groups of international cricketers (16 females, 28 males), professional rugby-league players (21 males), and non-sporting controls (20 females, 30 males). VRT was recorded via a button-press response to the sudden appearance of a stimulus (circular target—diameter 0.8°), that was presented centrally, or 7.5° to the left or right of fxation. The incidence and timing of saccades and blinks occurring from 450 ms before stimulus onset to 225 ms after onset were measured to quantify gaze stability. Our results show that (1) cricketers have faster VRT than controls; (2) blinks and, in particular, saccades are associated with slower VRT regardless of the level of sporting ability; (3) elite female cricketers had steadier gaze (fewer saccades and blinks) compared to female controls; (4) when we accounted for the presence of blinks and saccades, our group comparisons of VRT were virtually unchanged. The stability of gaze is not a factor that explains the difference between elite and control groups in VRT. Thus we conclude that better gaze stability cannot explain faster VRT in elite sports players. / Biotechnology and Biological Science Research Council (BBSRC, grant references: BB/J018163/1, BB/J016365/1 and BB/J018872/1)

Part of the aim of this thesis was to explore a model for producing very fast saccade latencies in the 80 to 120ms range. Its primary motivation was to explore a possible interaction by uniquely combining three independent saccade factors: the gap effect, target-feature-discrimination, and saccadic inhibition of return (IOR). Its secondary motivation was to replicate (in a more conservative and tightly controlled design) the surprising findings of Trottier and Pratt (2005), who found that requiring a high resolution task at the saccade target location speeded saccades, apparently by disinhibition. Trottier and Pratt’s finding was so surprising it raised the question: Could the oculomotor braking effect of saccadic IOR to previously viewed locations be reduced or removed by requiring a high resolution task at the target location? Twenty naïve untrained undergraduate students participated in exchange for course credit. Multiple randomised temporal and spatial target parameters were introduced in order to increase probability of exogenous responses. The primary measured variable was saccade latency in milliseconds, with the expectation of higher probability of very fast saccades (i.e. 80-120ms). Previous research suggested that these very fast saccades could be elicited in special testing circumstances with naïve participants, such as during the gap task, or in highly trained observers in non-gap tasks (Fischer & Weber, 1993). Trottier and Pratt (2005) found that adding a task demand that required naïve untrained participants to obtain a feature of the target stimulus (and to then make a discriminatory decision) also produced a higher probability of very fast saccade latencies. They stated that these saccades were not the same as saccade latencies previously referred to as express saccades produced in the gap paradigm, and proposed that such very fast saccades were normal. Carpenter (2001) found that in trained participants the probability of finding very fast saccades during the gap task increased when the horizontal direction of the current saccade continued in the same direction as the previous saccade (as opposed to reversing direction) – giving a distinct bimodality in the distribution of latencies in five out of seven participants, and likened his findings to the well known IOR effect. The IOR effect has previously been found in both manual key-press RT and saccadic latency paradigms. Hunt and Kingstone (2003) stated that there were both cortical top-down and oculomotor hard-wired aspects to IOR. An experiment was designed that included obtain-target-feature and oculomotor-prior-direction, crossed with two gap level offsets (0ms & 200ms-gap). Target-feature discrimination accuracy was high (97%). Under-additive main effects were found for each factor, with a three-way interaction effect for gap by obtain-feature by oculomotor-prior-direction. Another new three-way interaction was also found for anticipatory saccade type. Anticipatory saccades became significantly more likely under obtain-target-feature for the continuing oculomotor direction. This appears to be a similar effect to the increased anticipatory direction-error rate in the antisaccade task. These findings add to the saccadic latency knowledge base and in agreement with both Carpenter and Trottier and Pratt, laboratory testing paradigms can affect saccadic latency distributions. That is, salient (meaningful) targets that follow more natural oculomotor trajectories produce higher probability of very fast latencies in the 80-120ms range. In agreement with Hunt and Kingstone, there appears to be an oculomotor component to IOR. Specifically, saccadic target-prior-location interacts differently for obtain-target-feature under 200-ms gap than under 0ms-gap, and is most likely due predominantly to a predictive disinhibitory oculomotor momentum effect, rather than being due to the attentional inhibitory effect proposed for key-press IOR. A new interpretation for the paradigm previously referred to as IOR is offered that includes a link to the smooth pursuit system. Additional studies are planned to explore saccadic interactions in more detail.

O presente estudo avaliou o sistema oculomotor medido por movimentos oculares em bebês com diagnóstico de Displasia Broncopulmonar (DBP). Bebês com idade gestacional 37 semanas, dependentes de oxigênio em concentrações acima de 21% por mais de 28 dias foram incluídos no grupo DBP, bebês nascidos a Termo (idade gestacional > 37 semanas), não internados foram incluídos no grupo nascido a termo e bebês prematuros (idade gestacional < 37 semanas), que permaneceram internados e que não fizeram uso de oxigênio por mais de 10 dias foram incluídos no grupo prematuro. Os bebês dos três grupos tinham exame oftalmológico de biomicroscopia e de fundo de olho com resultados normais. Foram excluídos do estudo, bebês em uso de oxigênio sob ventilação mecânica e/ou drogas vasoativas, com diagnóstico de hemorragia intracraniana, retinopatia da prematuridade e malformações motoras e/ou neurológicas congênitas ou adquiridas identificadas no exame neonatal ou durante a estadia no berçário. Todos os bebês realizaram uma única avaliação binocular. As avaliações foram realizadas com os bebês sentados confortavelmente e eram compostas pela avaliação de quatro movimentos oculares: sacadas (SAC), perseguição lenta (PL), reflexo vestíbulo-ocular (RVO) e nistagmo optocinéticos (NOC). Os movimentos oculares foram transcritos em variável categórica (presente ou ausente) e para análise estatística foram feitas comparações entre o grupo DBP, grupo nascido a termo e grupo prematuro (Teste Cochran Q), para garantir a confiabilidade dos resultados apresentados durante a avaliação, 28% da amostra foi avaliada por três observadores e um teste de aderência X2 foi utilizado para medir a confiabilidade entre os três observadores. Durante o estudo foram avaliados 109 bebês, 107 foram incluídos no estudo, dois bebês, com IG < 37 semanas, foram excluídos por usarem oxigênio por um tempo igual há 15 dias. Dos 107 bebês avaliados, 23 foram inclusos no grupo DBP, 47 no grupo nascido a termo e 37 no grupo prematuro. Os bebês do grupo DBP tiveram IG média de 32 semanas ± 3 semanas, APGAR 1° minuto 6 ± 1, 5° minuto 8 ± 2, 37 dias em oxigênio ± 10 dias, na quantidade média de 2 L/min ± 0,5 L/min. O peso de nascimento, idade gestacional, APGAR NO 1° e 5° minutos do grupo nascido a termo, DBP e Prematuro diferem significativamente entre si (Teste Kruskal-Wallis p = 0.0000, 0.0000, 0.0000, 0.0013 e 0.0001, respectivamente). O grupo nascido a termo apresentou maiores valores quando comparado ao grupo DBP e prematuro. Bebês com DBP manifestam ausência de três dos quatro tipos de movimentos oculares medidos quando comparado com o grupo nascido a termo e prematuro (Teste Q Cochran onde Q > 2 e p, < 0,05) / This study evaluated the oculomotor system measured by eye movements in infants diagnosed with bronchopulmonary dysplasia (BPD). Infants 37 weeks gestational age, oxygen-dependent at concentrations above 21% for more than 28 days were included in the BPD group, term infants (gestational age > 37 weeks), not hospitalized were included in term groups and preterm infants (gestational age < 37 weeks), who remained hospitalized and did not use oxygen for more than 10 days were included in the premature group. The three groups of babies had eye examination and biomicroscopy of the fundus with normal results. Excluded from the study, babies on oxygen in mechanical ventilation and/ or vasoactive drugs; with a diagnosis of intracranial hemorrhage, retinopathy of prematurity, motor and/or neurological congenital or acquired malformations identified in neonatal or during the stay in the nursery. All infants made a single binocular assessment. The evaluations were conducted with babies seated comfortably and were composed by the evaluation of four eye movements: saccades (SAC), slow pursuit (PL), vestibuloocular reflex (VOR) and optokinetic nystagmus (NOC). Eye movements were transcribed into a categorical variable (present or absent) and statistical analysis were made between BPD group, term group and premature group (Cochran Q test) to ensure reliable of the results presented during the evaluation, 28 % of the sample was evaluated by three observers and an adherence X2 test was used to measure the reliable between three observers. During the study, 109 infants were evaluated, 107 were included in the study, two infants with GA < 37 weeks, were excluded by using oxygen for a time equal to 15 days. Of the 107 infants evaluated, 23 were included in the BPD group, 47 in the term group and 37 in the premature group. Babies in the BPD group had GA of 32 weeks ± 3 weeks, APGAR 1st minute 6 ± 1, 5th minutes 8 ± 2, 37 days ± 10 days in oxygen, in the median amount of 2 L / min ± 0.5 L / min. Birth weight, gestational age, APGAR score at 1st and 5th minutes from the term group, DBP and Premature differ significantly (Kruskal-Wallis test p = 0.0000, 0.0000, 0.0013 and 0.0001, respectively). The term group had higher values when compared to the BPD and premature. Babies with BPD manifest absence of three of the four types of eye movements measured when compared with the term group and preterm (Cochran Q test where Q > 2 and p < 0.05)

As próteses oculares têm a função de restabelecer a estética simultaneamente à manutenção da forma anatômica da cavidade orbital, preservando o tônus muscular palpebral e inibindo o colapso palpebral. Como poucos trabalhos científicos foram realizados para avaliar a recuperação de tônus muscular em indivíduos com necessidade de próteses oculares, este trabalho teve o objetivo de quantificar, por meio da eletromiografia, essa qualidade muscular e observar a atividade dos músculos óculo motores em pacientes não reabilitados, reabilitados e controle. A atividade eletromiográfica foi captada durante os repousos inicial e final e atividades que envolveram efetiva participação da musculatura nas seguintes condições clínicas: abertura e fechamento normais das pálpebras e abertura e fechamento forçados das pálpebras. Diante dos resultados apresentados nesse estudo, observou-se que a prótese ocular individualizada não interfere nos músculos óculo motores da hemiface contralateral à reabilitada; o contato da prótese ocular nos tecidos musculares remanescentes da cavidade anoftálmica realiza efeito mioestimulador e tanto no grupo reabilitado como no grupo controle, houve maior atividade eletromiográfica nos músculos orbiculares inferiores na ação de abertura e fechamento. / The ocular prosthesis is meant to restore the aesthetics while maintaining the anatomical shape of the orbital cavity, preserving the eyelid muscle tone by inhibiting the breakdown of the eyelid. As few scientific studies were conducted to evaluate the recovery of muscle tone in individuals that need ocular prosthesis, this study aimed through electromyography evaluate this muscle quality and observe the activity of eye muscles in patients not rehabilitated, rehabilitated and control. Electromyographic activity was captured during initial and final rest positions and activities involving active participation of muscles in the following clinical conditions: normal opening and closing eyelid and forced opening and closing eyelid. From the results presented in this study, it was concluded that the ocular prosthesis does not interfered in individual ocular motor muscles of the rehabilitated contralateral hemiface; the ocular prosthesis contact on the remaining tissue of the anophthalmic cavity did myostimulator effects, in the rehabilitated and control groups, EMG activities were greater in lower orbicular muscles at opening and closing actions.

Microsaccades are an important component of the small eye movements that constitute fixation, the basis of visual perception. The specific function of microsaccades has been a long-standing research problem. Only recently, conclusive evidence emerged, showing that microsaccades aid both visual perception and oculomotor control. The main goal of this thesis was to improve our understanding of the implementation of microsaccade generation within the circuitry of saccade control, an unsolved issue in oculomotor research. We make a case for a model according to which microsaccades and saccades result from mutually dependent motor plans, competing for expression. The model consists of an activation field, coding for fixation at its center and for saccades at peripheral locations; saccade amplitude increases with eccentricity. Activity during fixation spreads to slightly peripheral locations in the field and, thus, may result in the generation of microsaccades. Inhibition of remote and excitation of neighbouring locations govern the dynamics of the field, resulting in a strong competition between fixation and saccade generation. We propose that this common-field model of microsaccade and saccade generation finds a neurophysiological counterpart in the motor map of the superior colliculus (SC), a key brainstem structure involved in the generation of saccades. In a series of five behavioral experiments, we tested implications of the model. Predictions were derived concerning (1) the behavior of microsaccades in a given task (microsaccade rate, amplitude, and direction), (2) the interactions of microsaccades and subsequent saccades, and (3) the relationship between microsaccadic behavior and neurophysiological processes at the level of the SC. The results yielded strong support for the model at all three levels of analysis, suggesting that microsaccade statistics are indicative of the state of the fixation-related part of the SC motor map. / Mikrosakkaden sind ein wichtiger Bestandteil der kleinen Augenbewegungen, aus denen Fixationen, die Basis der visuellen Wahrnehmung, bestehen. Neuere Arbeiten erbrachten schlüssige Evidenz dafür, das Mikrosakkaden eine wichtige Rolle in der Wahrnehmung und der Blickbewegungskontrolle spielen. Hauptanliegen dieser Dissertation war es, unser Verständnis der Implementierung der Generierung von Mikrosakkaden im Kreislauf der Sakkadensteuerung zu vertiefen. Wir schlagen ein Modell vor, in dem Mikrosakkaden und Sakkaden konkurrierende Bewegungsprogramme darstellen, die um ihre Umsetzung wettstreiten. Das Modell besteht aus einem Aktivationsfeld, in dem Fixation im Zentrum und Sakkaden in der Peripherie repräsentiert sind (Sakkadenamplitude steigt mit der Exzentrizität). Aktivität während der Fixation breitet sich zu leicht peripheren Orten im Feld aus und kann so zur Generierung von Mikrosakkaden führen. Hemmung von entfernten und Erregung von benachbarten Orten bestimmen die Dynamik im Feld, was zu einem starken Wettstreit zwischen Fixation und Sakkadengenerierung beiträgt. Wir schlagen vor, dass dieses common-field model of microsaccade and saccade generation ein neurophysiologisches Pendant in der Bewegungskarte des colliculus superior (CS) findet, einer Struktur im Hirnstamm, die im starken Zusammenhang mit der Entstehung von Sakkaden steht. In fünf behavioralen Experimenten wurden Implikationen des Modells überprüft. Vorhersagen wurden auf drei Ebenen abgeleitet: (1) Verhalten der Mikrosakkaden in bestimmten Aufgaben (Mikrosakkadenrate, -amplitude und -richtung), (2) Interaktionen von Mikrosakkaden und nachfolgenden Sakkaden, (3) der Zusammenhang zwischen Mikrosakkadenverhalten und neurophysiologischen Prozessen auf der Ebene des CS. Die Ergebnisse unterstützten das Modell auf allen drei Analyseebenen. Mikrosakkaden scheinen ein Indikator der Fixationsaktivität in der Bewegungskarte des CS zu sein.

Background: Idiopathic parkinsonism is a neurodegenerative syndrome of unknown cause and includes Parkinson’s disease (PD) and atypical parkinsonian disorders. The atypical parkinsonian disorders are: Multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). The incidence rates of these diseases in Sweden are largely unknown. The diagnosis of each disease relies mainly on clinical examination although several imaging and laboratory parameters may show changes. A diagnosis based on clinical examination is especially difficult early in the course of each disease; diagnosis is easier later on when disease-charactersistic signs have evolved and become more prominent. However, even in later stages it is not uncommon that patients are misdiagnosed. PD can be divided into subgroups based on the main clinical symptoms, i. e. tremor dominant, postural instability and gait difficulty (PIGD), and indeterminate. The PIGD subtype has worse prognosis including higher risk of dementia. The aims were to study the incidence of idiopathic parkinsonism and the different specific parkinsonian disorders in the Umeåregion and to investigate the patients early in the course of the disease with brainmagnetic resonance tomography (MRI), external anal sphincterelectromyography (EAS-EMG) and oculomotor examination. Can these methods improve the differential diagnostic work-up and/or differentiate between the subtypes of PD? Methods: We examined all patients in our catchment area (142,000 inhabitants) who were referred to us due to a suspected parkinsonian syndrome. Our clinic is the only clinic in the area receiving referrals regarding movement disorders. During the period (January 1, 2004 through April 30,2009) 190 patients fulfilled the inclusion criteria and were included in the study. Healthy volunteers served as controls.  Results: Incidence: We found the highest incidences reported in the literature: PD (22.5/100,000/year), MSA(2.4/100,000/year), and PSP (1.2/100,000/year). No CBD patients were encountered. Brain MRI: Degenerative changes were common both in controls and PD. There were no differences between the PD subtypes. EAS-EMG: Pathological changes in EAS-EMG examination were common in PD, MSA and PSP. It was not possible to separate PD, MSA and PSP by the EAS-EMG examination. Oculomotor examination: Pathological results were common in all diagnosis groups compared to controls. It was not possible to separate PD, MSA and PSP or the PD subtypes with the help of oculomotor examination. Conclusions: The incidences of idiopathic parkinsonism, PD, MSA and PSP were higher than previously reported in the literature. It is not clear weather this is due to a true higher incidence in the Umeå region or a more effective casefinding than in other studies. MRI, EAS-EMG and oculomotor examination could not contribute to the differential diagnostic work-up between PD, MSA and PSP nor differentiate between PD subtypes early in the course of the disease.

Patients with Amyotrophic lateral sclerosis (ALS) often experience cognitive impairment that accompanies degeneration of the motor system. A valuable tool for assessing cognitive control over behaviour is the antisaccade task which requires: 1) inhibition of the automatic response to look towards an eccentric visual stimulus (prosaccade) to instead 2) redirect gaze in the opposite direction of the stimulus (antisaccade). Psychometric tests were used to quantify the degree of impairment, while eye tracking, functional magnetic resonance imaging (fMRI) and structural MRI were combined to identify the neural correlates of cognitive impairment in ALS. We predict ALS patients will have executive dysfunction and grey matter loss in executive and oculomotor control areas that will affect antisaccade performance and will alter the corresponding brain activation. ALS patients and age-matched controls participated in a rapid-event-related fMRI design with interleaved pro- and antisaccade trials. Catch trials (no stimulus presented after instructional cue to prepare pro- or antisaccade) allowed us to discern the preparatory period from the execution period. ALS patients were biased towards automatic saccade responses, and had greater difficulty with antisaccades relative to controls in terms of correct and timely responses. We found that worsened antisaccade performance in ALS correlated with the degree of cognitive impairment. Generally, we found trends of increased brain activation during the preparatory period of antisaccades in ALS patients compared to controls in most oculomotor areas; meanwhile few differences were seen during execution. Structural analyses revealed ALS patients had decreased grey matter thickness in frontotemporal and oculomotor regions such as the frontal and supplementary eye fields (FEF, SEF) and the dorsolateral prefrontal cortex (DLPFC). These findings suggest that loss of structural integrity and executive dysfunction may elicit compensation mechanisms to improve functional and behavioural performance. Despite this compensation, ALS patients still performed worse on antisaccades than controls. Further investigation to expand the current data set should improve our ability to assuredly identify the neural correlates of cognitive decline in ALS, and may provide a model system to use for critical evaluation of future therapies and interventions for ALS. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2011-09-22 14:20:39.704

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 114-122).