• 제목/요약/키워드: Ocular motor

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Abnormal Ocular Motilities in Movement Disorders (이상운동질환에서의 안구운동장애)

  • Park, Hong-Kyun;Kim, Ji-Soo
    • Annals of Clinical Neurophysiology
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    • v.13 no.1
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    • pp.13-20
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    • 2011
  • Neuro-ophthalmological findings are common and occasionally prominent features in movement disorders. Accordingly, careful evaluation of the ocular motor functions may provide valuable information in early detection of the diseases and monitoring of the progression. Furthermore, accurate assessment of the abnormal ocular motor findings aids in understanding the pathophysiology and mechanisms of the movement disorders, and in their differential diagnosis. Ocular motility examination should include bedside evaluation and laboratory recording of the fixational abnormalities, saccades, smooth pursuit, the vestibulo-ocular reflex, optokinetic nystagmus, and vergence eye movements. In this review, we will discuss various ocular motor findings in ataxia and parkinsonian syndromes, and hyperkinetic movement disorders.

A Study of Evaluating Eye Movement Based on Ocular Motor Score for Children with Spastic Cerebral Palsy

  • Jeong, Seo-Young;Oh, Tae-Young
    • The Journal of Korean Physical Therapy
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    • v.32 no.6
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    • pp.341-347
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    • 2020
  • Purpose: The purpose of this study is to introduce a tool for evaluating eye movement and analyze the reliability of measurement based on 10 cases of evaluating the oculomotor function of children with spastic cerebral palsy Methods: The participants were selected by 6 medical and welfare institutions in Busan as GMFCS grade 1-3 among spastic diplegia and hemiplegia. Seven examiners evaluated 3 children for the evaluation of inter-rater agreement of Ocular Motor Score (OMS) and evaluated the condition of the ocular motor of 10 children using OMS, a re-examination was performed at six weeks after the initial examination. SPSS ver.25.0 was used to calculate the interclass correlation coefficient and Wilcoxon's signed-rank test, Mann Whitney-U test. Results: The inter-rater agreement of OMS was 0.89. Second mean values were decreased compared first examination in motility/ductions/version, saccades and smooth pursuit, but there was no significant difference. Children under 6 years old had a high mean value of saccades in first examination and the motility/ductions/version, fixation, saccades in second examination, but there was no significant difference. Spastic diplegia children's mean values were higher in head posture, fixation in 8 gaze directions than hemiplegia children in both first and second examination, but there were no significant differences. Conclusion: Ocular motor function in 10 children of spastic children who participated in the study and could see that the scores was differed depending on age, type, grade of cerebral palsy. OMS may be available for this purpose.

Physiology of Eye Movements (안구 운동의 생리)

  • Kim, Ji Soo
    • Annals of Clinical Neurophysiology
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    • v.1 no.2
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    • pp.173-181
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    • 1999
  • Eye movements serve vision by placing the image of an object on the fovea of each retina, and by preventing slippage of images on the retina. The brain employs two modes of ocular motor control, fast eye movements (saccades) and smooth eye movements. Saccades bring the fovea to a target, and smooth eye movements prevent retinal image slip. Smooth eye movements comprise smooth pursuit, the optokinetic reflex, the vestibulo-ocular reflex (VOR), vergence, and fixation. Saccades achieve rapid refixation of targets that fall on the extrafoveal retina by moving the eyes at peak velocities that can exceed $700^{\circ}/s$. Various brain lesions can affect saccadic latency, velocity, or accuracy. Smooth pursuit maintains fixation of a slowly moving target. The pursuit system responds to slippage of an image near the fovea in order to accelerate the eyes to a velocity that matches that of the target. When smooth eye movements velocity fails to match target velocity, catch-up saccades are used to compensate for limited smooth pursuit velocities. The VOR subserves vision by generating conjugate eye movements that are equal and opposite to head movements. If the VOR gain (the ratio of eye velocity to head velocity) is too high or too low, the target image is off the fovea, and head motion causes oscillopsia, an illusory to-and-fro movement of the environment.

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Functional Relationship between the Vestibular Canals and the Extraocular Oblique Muscles (미노반규관(迷路半規管)과 외안사근(外眼斜筋)의 기능적(機能的) 관계(關係)에 관(關)하여)

  • Kim, Jeh-Hyub
    • The Korean Journal of Physiology
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    • v.6 no.2
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    • pp.49-56
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    • 1972
  • This experiment was designed to explore specific functional relationship between the vestibular canals and the extraocular oblique muscles by observing the isometric tension responeses of the muscles to the selected vestibular canal excitation. The vestibular excitation was simulated by either stimulation of the individual canal nerve or endolymphatic fluid displacement in each canal. Each canal nerve was subjected to square wave pulses with a monopolar wire electrode placed closely to the ampullary nerve endings for electrical stimulation, and a fine stainless cannula was introduced into the each canal toward the ampulla and a minute amount $(0.5{\sim}3.5\;microliter)$ of fluid was injected in or ejected out by means of a microsyringe connected to the cannula to produce ampullopetal or ampullofugal displacement of endolymphatic fluid. The superior oblique muscle was contracted by the excitation of homolateral canals and was relaxed by contralateral canals. On the contrary, the inferior oblique was contracted by the contralateral canals and was relaxed by the homolateral canals. Summation of excitatory and inhibitory canal effects from the bilateral vestibular system was demonstrable on the tension changes of the oblique muscles. Excitation of either dual or triple canals of the unilateral vestibular system also caused summation effect on the tension response of the oblique pair; thus multiple signals from the different ampullary receptors seems to be converged into the relevant ocular motor muclei. Since the superior and inferior obliques are known to receive their motor fibers from the contralateral trochlear nuclei and intermediate nuclei of the homolateral oculomotor complex respectively, the above experimental evidences indicate that the ocular motor nuclei for oblique muscles receive excitatory signals from the contralateral vestibular canals and inhibitory signals from the homolateral canals.

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Design of Computer Access Devices for Severly Motor-disability Using Bio-potentials (생체전위를 이용한 중증 운동장애자들을 위한 컴퓨터 접근제어장치 설계)

  • Jung, Sung-Jae;Kim, Myung-Dong;Park, Chan-Won;Kim, Il-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.55 no.11
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    • pp.502-510
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    • 2006
  • In this paper, we describe implementation of a computer access device for the severly motor-disability. Many people with severe motor disabilities need an augmentative communication technology. Those who are totally paralyzed, or 'locked-in' cannot use conventional augmentative technologies, all of which require some measure of muscle control. The forehead is often the last site to suffer degradation in cases of severe disability and degenerative disease. For example, In ALS(Amyotrophic Lateral Sclerosis) and MD(Muscular dystrophy) the ocular motorneurons and ocular muscles are usually spared permitting at least gross eye movements, but not precise eye pointing. We use brain and body forehead bio-potentials in a novel way to generate multiple signals for computer control inputs. A bio-amplifier within this device separates the forehead signal into three frequency channels. The lowest channel is responsive to bio-potentials resulting from an eye motion, and second channel is the band pass derived between 0.5 and 45Hz, falling within the accepted Electroencephalographic(EEG) range. A digital processing station subdivides this region into eleven components frequency bands using FFT algorithm. The third channel is defined as an Electromyographic(EMG) signal. It responds to contractions of facial muscles and is well suited to discrete on/off switch closures, keyboard commands. These signals are transmitted to a PC that analyzes in a time series and a frequency region and discriminates user's intentions. That software graphically displays user's bio-potential signals in the real time, therefore user can see their own bio-potentials and control their physiological signals little by little after some training sessions. As a result, we confirmed the performance and availability of the developed system with experimental user's bio-potentials.

A case of a patient with ocular motor dysfunction treated with Traditional Korean Medicine (안구운동장애를 주소로 하는 환자 치험 1례)

  • Woo, Ji Myung;Yei, Young-chul;Jin, Chul;Kim, Young-seok;Cho, Ki-ho;Mun, Sang-Kwan;Jung, Woo-sang
    • The Journal of the Society of Stroke on Korean Medicine
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    • v.15 no.1
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    • pp.85-89
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    • 2014
  • ■ Objectives The purpose of this clinical study is to evaluate the effect of Traditional Korean Medicine(TKM) on a patient with abnormal eye movement. ■ Methods A patient with abnormal eye movement of limbs diagnosed with midbrain infarction was treated with herbal medication, acupuncture, moxa, and herbal medical injection. Then we evaluated the improvement by measuring range of eye movement. ■ Results Increase of range of eye movement and improvement of symptom of diplopia were observed after the TKM treatment. ■ Conclusion This study proved the effect of TKM treatment on abnormal eye movement due to midbrain infarction.

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Recent Clinical Research on Effect of Acupuncture for Strabismus (사시의 침치료에 대한 최근 임상 연구 동향)

  • Lee, Ji Na;Lee, Sun Haeng;Lee, Jin Yong
    • The Journal of Pediatrics of Korean Medicine
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    • v.30 no.2
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    • pp.23-30
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    • 2016
  • Objectives The purpose of this study is to investigate recent clinical studies on effect of acupuncture for strabismus in Korea and other countries. We have analyzed 10 years (from 2006 to 2015) of case studies and randomized controlled trials (RCT) on effect of acupuncture for strabismus. Methods The search database includes Oasis, KTKP (Korean Traditional Knowledge Portal), Medline, Embase, and Cochrane library. To narrow the search, the following key search terms were used: 'strabismus, acupuncture'. The search was limited to the publication date from 2006 to 2015. 7 case studies and 5 control studies were selected for analysis. Results and Conclusions 1. The acupuncture treatment is effective for paralytic strabismus 2. The studies used BL1, GB1, ST2, TE23, GB15, EX-HN5, ST1, and LI4 acupoints and also an electroacupuncture treatment, which is 15 minutes of extraocular muscle stimulation, was used. 3. Degree of strasbismus was tested by Ocular motor range test, Corneal light reflex test, Ocular abducent scale test (Scott and Kraft, Diploptic range test).

Cerebellar Control of Saccades (소뇌의 단속안구운동 조절)

  • Choi, Jae-Hwan;Choi, Kwang-Dong
    • Annals of Clinical Neurophysiology
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    • v.15 no.2
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    • pp.37-41
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    • 2013
  • Saccades are rapid eye movements that shift the line of sight between successive points of fixation. The cerebellum calibrates saccadic amplitude (dorsal vermis and fastigial nucleus) and the saccadic pulse-step match (flocculus) for optimal visuo-ocular motor behavior. Based on electrophysiology and the pharmacological inactivation studies, early activity in one fastigial nucleus could be important for accelerating the eyes at the beginning of a saccade, and the later activity in the other fastigial nucleus could be critical for stopping the eye on target, which is controlled by inhibitory projection from the dorsal vermis. The cerebellum could monitor a corollary discharge of the saccadic command and terminate the eye movement when it is calculated to be on target. The fastigial nucleus and dorsal vermis also participate in the adaptive control of saccadic accuracy.

Selective impairment of the rapid eye movements in myotonic dystrophy

  • Kim, Sung-Hee;Park, Jin-Sung
    • Annals of Clinical Neurophysiology
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    • v.21 no.2
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    • pp.94-97
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    • 2019
  • The patients with myotonic dystrophy (MD) show ocular motor abnormalities including strabismus, vergence deficits, and inaccurate or slow saccades. Two theories have been proposed to explain the oculomotor deficits in MD. The central theory attributes the defects of eye movements of MD to the involvement of the central nervous system while the muscular theory attributes to dystrophic changes of the extraocular muscles. A 58-year-old woman with MD showed selective slowing of horizontal saccades and reduced peak velocities for both horizontal canals in head impulse tests, while smooth-pursuit eye movements and vertical head impulse responses were normal. This case suggests that the extraocular muscles-as a final common pathway of the voluntary saccade and reflexive vestibular eye movements-may better explain the defective rapid eye movements observed in MD.

A Study on Process Analysis of Visual Understanding on accordance in Attention Time (주시시간에 따른 시각적 이해과정 분석에 관한 연구)

  • Kim, Jong-Ha
    • Korean Institute of Interior Design Journal
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    • v.20 no.4
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    • pp.101-108
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    • 2011
  • When observing an object in a space, a part of it is remembered into our perception in the time for paying attention or conscious observation and it reaches to our visual understanding. In this study, it examined characteristics by each subject through the process of visual understanding by changes in such observation time. The results from this study are summarized as belows: First, through analysis of the observation data focused on the distance between the observed points, it was able to apply those visual theories organized before to the analysis of characteristics of the time for understanding by each subject. Second, there showed big differences in the time for visual understanding by each subject according to changes in the observation time so that it was found that there were big differences according to the characteristics of subject's intention or purpose of the observation of a space. Third, as the number of continuous observation gives an important clue in judgement of how well the space was understood, it was able to compare and organize the mutual characteristics of the time the attention was concentrated, the time observed intentionally and the time understood visually. Fourth, it was found that the shorter subjects gave the intentional observation in observing a space, the longer they spent the time for paying attention, while the less they could understand it visually.