Athletic potential is one of the most complex human traits. An elite athlete is produced from a complex interaction of an innumerable number of traits exhibited by the athlete. However, it’s not clear whether these traits are innate, allowing the athlete to excel, or, alternatively, are a consequence of practice. To be successful, athletes rely heavily on sensory information from the visual and vestibular systems. This study investigated the relationship eye movement control has with innate athleticism by comparing the saccadic and Vestibulo-Ocular Reflex (VOR) responses of former, no longer practicing, elite athletes against their age and gender matched counterparts who were non-elite or non-athletes. Results showed subjects who participated in athletic activities longer (regardless of type or level achieved), showed both significantly better VOR suppression capabilities, as well as higher head velocities while suppressing their VOR. Although, these results are correlative in nature, they do not support the potential that VOR suppression is a learned trait of athletes. A longitudinal study would be required to assess this relationship fully.

Dizziness is a common, multifactorial problem that causes reductions in quality of life and is a major risk factor for falls, but the role of vision is a very under-researched area. This study aimed to investigate any link between dizziness and vision and to establish if changes in spectacle lens correction could elicit dizziness symptoms. A link between dizziness and self-reported poor vision was indicated in the epidemiological literature as shown by a systematic review, provided lightheadedness was not included in the definition of dizziness. Cases of individuals who reported vision-related dizziness were investigated to determine potential areas of research for this thesis and subsequently two studies investigated the effects of refractive correction changes on dizziness status. The first study was limited by logistical problems, although it highlighted limitations in the short form of the Dizziness Handicap Inventory that was used to quantify dizziness. Results of an optometry practice recheck study found that oblique cylindrical changes were significantly more likely to be associated with dizziness symptoms than other spectacle lens changes. It also highlighted that optometrists do not ask/record about dizziness symptoms with only 4% of records including “dizziness” as a problem when 38% of patients reported dizziness symptoms when directly asked. All studies highlighted a need for a patient-reported outcome measure to be designed to assess vision-related dizziness. Literature review, interviews with experts and patients and focus groups led to the development of a pilot questionnaire and subsequently a 25-item Vision-Related Dizziness instrument, the VRD-25. This was validated using responses from 223 respondents, with 79 participants completing the questionnaire a second time to provide test-retest data. Two subscales of VRD-12-frequency (VRD-12f) and VRD-13-severity (VRD-13s) were shown to be unidimensional and had good psychometric properties, convergent validity and test-retest repeatability. The VRD-25 is the only patient-reported outcome measure developed to date to assess vision related dizziness and will hopefully provide the platform to further grow this under-researched area that seems likely to provide important clinical information. / College of Optometrists sponsored the research with a Postgraduate Research Scholarship

Introdução: Desde sua primeira descrição na década de 40 o espectro de aplicação da reabilitação vestibular vem crescendo, tornando-se opção de tratamento em disfunções vestibulares periféricas, incluindo as uni e bilaterais, e em doenças do sistema nervoso central. O presente estudo avalia a eficácia de exercícios que estimulam a adaptação do reflexo vestíbulo-ocular em indivíduos com quadro agudo de vertigem. Métodos: neste estudo clínico prospectivo foram avaliados indivíduos aleatoriamente alocados em um grupo de estudo, que realizou exercícios para adaptação do reflexo vestíbulo-ocular, e em um grupo controle, que realizou exercícios placebo. Os critérios de inclusão foram história de pelo menos um episódio de vertigem nos últimos cinco dias, idade acima de 18 anos, e alteração em pelo menos dois dos testes objetivos de equilíbrio (teste de Romberg, teste de Fukuda e \"head-shaking\" nistagmo) e/ou presença de nistagmo espontâneo. Os pacientes de ambos os grupos foram orientados a utilizar dimenidrato na dose máxima de 150 mg ao dia, divididas em três doses, podendo auto-regular a dose conforme a intensidade dos sintomas apresentados. Foram excluídos indivíduos que tivessem utilizado medicação com ação no sistema vestibular nos últimos sete dias, com presença de alterações sugestivas de doença do sistema nervoso central, diagnóstico de vertigem posicional paroxística benigna ou de fístula perilinfática. Os pacientes foram avaliados, no início do estudo e em três visitas subseqüentes, realizadas nos períodos de três a cinco dias, sete a dez dias e dezoito a vinte e um dias após o início da pesquisa. Em todas as visitas a avaliação foi realizada por meio de notas atribuídas à intensidade dos sintomas (escala analógica visual), quantidade de medicação utilizada e resultados dos testes de equilíbrio. Resultados: Foram analisados 87 xxxv indivíduos, 45 no grupo de estudo e 42 no grupo controle. Na avaliação inicial os grupos eram semelhantes do ponto de vista estatístico em relação ao sexo e idade dos pacientes, tempo decorrido entre o início dos sintomas e a primeira avaliação, intensidade dos sintomas e achados de exame físico. O grupo de estudos apresentou intensidade de sintomas inferior ao grupo controle nas segunda e terceira avaliações; na quarta e última avaliação ambos os grupos apresentaram sintomatologia semelhante. A quantidade de medicação utilizada pelos pacientes do grupo de estudos foi inferior à utilizada pelo grupo controle em todos as avaliações realizadas. Não houve diferença entre os grupos em relação ao desaparecimento do nistagmo espontâneo exceto na terceira avaliação. A proporção de pacientes com teste de Romberg alterado foi menor no grupo de estudo quando comparada ao grupo controle nas segunda (tendência à significância estatística) e terceira avaliações, não havendo diferença entre os grupos na última avaliação. Nos testes de Fukuda e de \"head-shaking\" nistagmo não houve diferença entre os grupos em relação à proporção de testes alterados nas primeira e segunda avaliações, entretanto nas terceira e quarta avaliações o grupo de estudos teve menor proporção de testes alterados. Conclusões: O grupo submetido aos exercícios para adaptação do reflexo vestíbulo-ocular obteve melhora clínica mais rápida, fez uso de quantidade menor de dimenidrato e apresentou normalização dos testes clínicos de equilíbrio mais precocemente quando comparado ao grupo controle / Introduction: Since its first description in 1940 decade, the spectrum of use of vestibular rehabilitation has broadened and nowadays comprises unilateral, bilateral and even central vestibular disorders. The objective of this study is to evaluate the effect of exercises for adaptation of the vestibuloocular reflex in patients with acute vertigo. METHODS: Study design: prospective randomized trial, patients blinded to assignment groups. The study population had the following characteristics: = 18 years of age, at least one episode of vertigo in the last five days, negative results in at least two objective vestibular tests and/or presence of spontaneous nystagmus. The exclusion criteria were: use of any medication interfering with the vestibular system in the past seven days, clinical history or physical findings indicative of central nervous system disorders, clinical diagnosis of benign paroxysmal positional vertigo or perilymphatic fistula. Patients were randomly allocated to the intervention and placebo controlled groups. Intervention group performed exercises for adaptation of the vestibulo-ocular reflex; control group performed placebo exercises. Both groups were instructed to use dimenhydrinate and self-adjust the dose according to the intensity of their symptoms (up to 150mg/day). Patients evaluated by the assessment of the intensity of symptoms, by analogue visual scale, neuro-otological examination (presence of spontaneous nystagmus, Romberg test, Fukuda test and head-shaking nystagmus) and need to use the medication. There were three appointments in the follow-up period: three to five days, seven to ten days and eighteen to twenty one days after the initial evaluation. Results: There were 87 patients eligible for the study, 45 in the intervention group and 42 in the control group. At the initial evaluation, there was no statistically significant difference between the intervention and control groups in terms of sex, age, interval from onset of symptoms to inclusion in the study, intensity xxxvii of symptoms and neuro-otological tests results. Intensity of symptoms: the mean of the patients\' analogue visual scale score was similar for the intervention and control groups at the initial evaluation. At the second and third evaluations the mean score of the intervention group was significantly smaller. At the fourth and final evaluation, the groups were similar again. In the intervention group the amount of medication used by patients was always smaller than in the control group. Presence of spontaneous nystagmus was similar in between the groups at all but the third evaluation. As to the Romberg test results, the proportion of patients with a positive test was smaller for the intervention group at the second and third evaluations (borderline significant for the second intervention). At the fourth and final evaluation, the groups were similar again. As to the Fukuda and headshaking nystagmus tests, results were similar, at the third and forth evaluations the intervention group performed better than the control group. Conclusions: Vestibular exercises for adaptation of the vestibulo-ocular reflex have beneficial effects on treatment of patients with acute vertigo. The intervention group recovered faster, used a reduced amount of medication and performed better on balance tests as compared to the control group

No description available.

The human vestibulo-ocular reflex (VOR) stabilizes gaze during head movement. The reflex is typically tested in a clinic or laboratory using passive rotations or artificial stimuli which measure the amount of damage the vestibular apparatus has suffered. However, during everyday activities the vestibular system is stimulated by active, self generated head movements. Head movements are often rapid and associated with the goal of achieving either gaze-fixation or re-fixation. Patients who complain of on-going symptoms will typically identify a particular position or movement that aggravates their symptoms in their everyday life. There is a need to identify objective parameters which correlate with the subjective complaints of patients whose symptoms persist after vestibular damage. In the first study, a gaze-refixation task, patients who complain of ongoing symptoms (poorly-compensated), during rapid head turns, after unilateral vestibular de-afferentation (uVD) were compared with those who did not have the same complaints (well-compensated) and normal subjects. Well- and poorly-compensated groups were sorted according to responses on a standardized questionnaire. All subjects were then located in a real-world, non-laboratory environment in which poorly-compensated subjects reported experiencing symptoms. Each subject’s head, eye and gaze displacement and velocity, head rotation frequency and blink or eye-lid closure were measured and analysed and compared between ipsi- and contra-lesional head rotations within and between subject groups. When subjects are able to generate their own active head rotations it has been suggested that a number of vestibular and extra-vestibular strategies might be employed to compensate for an impaired VOR. In subsequent studies, high resolution scleral search coils were used to identify the compensatory mechanisms used during active head rotations during a gaze-fixation task. A corrective saccade is typically observed during passive ipsilesional head rotations or “impulses” and might be potentiated during rapid, active or self-generated head rotations. The conditions which predict or contribute to the generation of the rapid, corrective eye movement were investigated. The results were compared with responses to passive head impulses of matched velocity and acceleration to determine if active head impulses could be used to identify a lesioned vestibular apparatus as is routinely clinically achieved with passive head impulses.

The human vestibulo-ocular reflex (VOR) stabilizes gaze during head movement. The reflex is typically tested in a clinic or laboratory using passive rotations or artificial stimuli which measure the amount of damage the vestibular apparatus has suffered. However, during everyday activities the vestibular system is stimulated by active, self generated head movements. Head movements are often rapid and associated with the goal of achieving either gaze-fixation or re-fixation. Patients who complain of on-going symptoms will typically identify a particular position or movement that aggravates their symptoms in their everyday life. There is a need to identify objective parameters which correlate with the subjective complaints of patients whose symptoms persist after vestibular damage. In the first study, a gaze-refixation task, patients who complain of ongoing symptoms (poorly-compensated), during rapid head turns, after unilateral vestibular de-afferentation (uVD) were compared with those who did not have the same complaints (well-compensated) and normal subjects. Well- and poorly-compensated groups were sorted according to responses on a standardized questionnaire. All subjects were then located in a real-world, non-laboratory environment in which poorly-compensated subjects reported experiencing symptoms. Each subject’s head, eye and gaze displacement and velocity, head rotation frequency and blink or eye-lid closure were measured and analysed and compared between ipsi- and contra-lesional head rotations within and between subject groups. When subjects are able to generate their own active head rotations it has been suggested that a number of vestibular and extra-vestibular strategies might be employed to compensate for an impaired VOR. In subsequent studies, high resolution scleral search coils were used to identify the compensatory mechanisms used during active head rotations during a gaze-fixation task. A corrective saccade is typically observed during passive ipsilesional head rotations or “impulses” and might be potentiated during rapid, active or self-generated head rotations. The conditions which predict or contribute to the generation of the rapid, corrective eye movement were investigated. The results were compared with responses to passive head impulses of matched velocity and acceleration to determine if active head impulses could be used to identify a lesioned vestibular apparatus as is routinely clinically achieved with passive head impulses.

Introdução: Desde sua primeira descrição na década de 40 o espectro de aplicação da reabilitação vestibular vem crescendo, tornando-se opção de tratamento em disfunções vestibulares periféricas, incluindo as uni e bilaterais, e em doenças do sistema nervoso central. O presente estudo avalia a eficácia de exercícios que estimulam a adaptação do reflexo vestíbulo-ocular em indivíduos com quadro agudo de vertigem. Métodos: neste estudo clínico prospectivo foram avaliados indivíduos aleatoriamente alocados em um grupo de estudo, que realizou exercícios para adaptação do reflexo vestíbulo-ocular, e em um grupo controle, que realizou exercícios placebo. Os critérios de inclusão foram história de pelo menos um episódio de vertigem nos últimos cinco dias, idade acima de 18 anos, e alteração em pelo menos dois dos testes objetivos de equilíbrio (teste de Romberg, teste de Fukuda e \"head-shaking\" nistagmo) e/ou presença de nistagmo espontâneo. Os pacientes de ambos os grupos foram orientados a utilizar dimenidrato na dose máxima de 150 mg ao dia, divididas em três doses, podendo auto-regular a dose conforme a intensidade dos sintomas apresentados. Foram excluídos indivíduos que tivessem utilizado medicação com ação no sistema vestibular nos últimos sete dias, com presença de alterações sugestivas de doença do sistema nervoso central, diagnóstico de vertigem posicional paroxística benigna ou de fístula perilinfática. Os pacientes foram avaliados, no início do estudo e em três visitas subseqüentes, realizadas nos períodos de três a cinco dias, sete a dez dias e dezoito a vinte e um dias após o início da pesquisa. Em todas as visitas a avaliação foi realizada por meio de notas atribuídas à intensidade dos sintomas (escala analógica visual), quantidade de medicação utilizada e resultados dos testes de equilíbrio. Resultados: Foram analisados 87 xxxv indivíduos, 45 no grupo de estudo e 42 no grupo controle. Na avaliação inicial os grupos eram semelhantes do ponto de vista estatístico em relação ao sexo e idade dos pacientes, tempo decorrido entre o início dos sintomas e a primeira avaliação, intensidade dos sintomas e achados de exame físico. O grupo de estudos apresentou intensidade de sintomas inferior ao grupo controle nas segunda e terceira avaliações; na quarta e última avaliação ambos os grupos apresentaram sintomatologia semelhante. A quantidade de medicação utilizada pelos pacientes do grupo de estudos foi inferior à utilizada pelo grupo controle em todos as avaliações realizadas. Não houve diferença entre os grupos em relação ao desaparecimento do nistagmo espontâneo exceto na terceira avaliação. A proporção de pacientes com teste de Romberg alterado foi menor no grupo de estudo quando comparada ao grupo controle nas segunda (tendência à significância estatística) e terceira avaliações, não havendo diferença entre os grupos na última avaliação. Nos testes de Fukuda e de \"head-shaking\" nistagmo não houve diferença entre os grupos em relação à proporção de testes alterados nas primeira e segunda avaliações, entretanto nas terceira e quarta avaliações o grupo de estudos teve menor proporção de testes alterados. Conclusões: O grupo submetido aos exercícios para adaptação do reflexo vestíbulo-ocular obteve melhora clínica mais rápida, fez uso de quantidade menor de dimenidrato e apresentou normalização dos testes clínicos de equilíbrio mais precocemente quando comparado ao grupo controle / Introduction: Since its first description in 1940 decade, the spectrum of use of vestibular rehabilitation has broadened and nowadays comprises unilateral, bilateral and even central vestibular disorders. The objective of this study is to evaluate the effect of exercises for adaptation of the vestibuloocular reflex in patients with acute vertigo. METHODS: Study design: prospective randomized trial, patients blinded to assignment groups. The study population had the following characteristics: = 18 years of age, at least one episode of vertigo in the last five days, negative results in at least two objective vestibular tests and/or presence of spontaneous nystagmus. The exclusion criteria were: use of any medication interfering with the vestibular system in the past seven days, clinical history or physical findings indicative of central nervous system disorders, clinical diagnosis of benign paroxysmal positional vertigo or perilymphatic fistula. Patients were randomly allocated to the intervention and placebo controlled groups. Intervention group performed exercises for adaptation of the vestibulo-ocular reflex; control group performed placebo exercises. Both groups were instructed to use dimenhydrinate and self-adjust the dose according to the intensity of their symptoms (up to 150mg/day). Patients evaluated by the assessment of the intensity of symptoms, by analogue visual scale, neuro-otological examination (presence of spontaneous nystagmus, Romberg test, Fukuda test and head-shaking nystagmus) and need to use the medication. There were three appointments in the follow-up period: three to five days, seven to ten days and eighteen to twenty one days after the initial evaluation. Results: There were 87 patients eligible for the study, 45 in the intervention group and 42 in the control group. At the initial evaluation, there was no statistically significant difference between the intervention and control groups in terms of sex, age, interval from onset of symptoms to inclusion in the study, intensity xxxvii of symptoms and neuro-otological tests results. Intensity of symptoms: the mean of the patients\' analogue visual scale score was similar for the intervention and control groups at the initial evaluation. At the second and third evaluations the mean score of the intervention group was significantly smaller. At the fourth and final evaluation, the groups were similar again. In the intervention group the amount of medication used by patients was always smaller than in the control group. Presence of spontaneous nystagmus was similar in between the groups at all but the third evaluation. As to the Romberg test results, the proportion of patients with a positive test was smaller for the intervention group at the second and third evaluations (borderline significant for the second intervention). At the fourth and final evaluation, the groups were similar again. As to the Fukuda and headshaking nystagmus tests, results were similar, at the third and forth evaluations the intervention group performed better than the control group. Conclusions: Vestibular exercises for adaptation of the vestibulo-ocular reflex have beneficial effects on treatment of patients with acute vertigo. The intervention group recovered faster, used a reduced amount of medication and performed better on balance tests as compared to the control group

In this study we examined dynamic visual acuity as a functional testing of the vestibulo- ocular reflex. Two groups were examined: 22 healthy seniors and 22 healthy young people as controls. We used two types of situations for testing: while walking on a treadmill at a speed of 2, 4 and 5 kmph, and with a subject's head passively moved in yaw and pitch plane. Visual acuity was measured with optotype charts (for the walking test it was a standard Snellen optotype chart at 6 m distance, for the test of head moves it was a Jaeger chart at 30 cm distance). The values obtained in these ways we related to values of a subject's static visual acuity, measured in the same conditions, just before the dynamic situations were examined. We found significant difference of dynamic visual acuity in senior group within each condition tested. We also found a significant decline as for difference of dynamic visual acuity in the senior group compared to young subjects - in the walking test at 4 and 5 kmph and in both head-moving conditions. These results indicate age-related impairment in function of vestibulo-ocular reflex. Based on our results, the test of passive head moves appears to be more suitable for ordinary clinical examination of dynamic visual acuity.

No description available.

This thesis deals with the evaluation of the vestibulo-ocular reflex in patients indicated for neurosurgical resection of vestibular schwannoma, executed at the Motol University Hospital. To evaluate the function of the vestibulo-ocular reflex, three types of clinical examinations were used. In periods before the surgery, early after the surgery and before leaving the hospital we monitored the patients' ability to perceive subjective visual vertical, which reflects tonic function of otolith organs. Before the surgery we also tested relative dynamic visual acuity during passive isolated head movements in the transversal plane, whose impairment is related to dysfunction of lateral semicircular canals. Furthermore, we obtained patients' preoperative values achieved in caloric reflex test. In the early postoperative period, bordered by the first day after the vestibular schwannoma surgery and the last day of the hospitalization, patients underwent specialized vestibular rehabilitation. Based on statistical analysis of acquired data, we found out that in some patients there was a lesion of the vestibulo-ocular reflex already before the surgery and moreover, there was a correlation between dysfunction of translational and rotational parts of the vestibulo-ocular reflex. Although variance of subjective...