Effects of vestibular spontaneous nystagmus on visual smooth pursuit function / 中华耳鼻咽喉头颈外科杂志

Objective: The aim of the study is to analyze the effects of vestibular spontaneous nystagmus(SN) on the smooth pursuit function of visual ocularmotor system. Methods: A total of 46 patients with acute unilateral peripheral vestibular syndrome with SN (26 cases of vestibular neuritis, 6 cases of Ramsay Hunt Syndrome (RHS) with vertigo, 14 cases of sudden deafness with vertigo) were included in this work. In the study group, the results of SPT and SN test with videonystagmography(VNG) were also reviewed. Taking SPT parameters, the influence of SN intensity on SPT gain, asymmetry and waveform and their correlation were analyzed.SPSS19.0 software was used for statistical analysis. Results: Among the 46 patients, there were 36 cases of SN pointing to the healthy side(SN intensity range of 2.68°/s-32.53°/s), and 10 cases of SN pointing to the affected side (SN intensity range of 2.66°/s-16.54°/s). SN intensity was divided into 3 groups, including light(0.50°/s-5.00°/s), medium(5.01°/s-10.00°/s) and strong(>10.01°/s), accounting for 14 cases(30.4%), 18 cases(39.1%) and 14 cases(30.4%), respectively. The differences of the gain of SPT to the fast phase and slow phase direction in the overall groups and light, medium and strong groups of SN intensity respectively were statistically significant(ttotal=13.338, tlight=6.184, tmedium=8.436, tstrong=8.477, all of P<0.001). The difference of SPT gain in SN fast phase direction between groups with different SN intensity was statistically significant(F=9.639, P<0.001),there was no statistically significant difference in SPT gain between the groups on the SN slow phase direction(F=1.137, P=0.330).The SN intensity significantly negatively correlated with the SPT gain of the fast phase direction of SN (r=-0.433, P=0.003), that was, the SPT gain on the fast phase direction of SN decreased with the increase of SN intensity. There was no significant correlation between SN intensity and the gain of SPT on the slow phase direction of SN (r=-0.061, P=0.687). SPT waveform analysis showed that type I, type II and type III accounted for 8 cases(17.4%), 21 cases(45.6%) and 17 cases(37.0%), respectively. The corresponding mean values of SN intensity were (3.71±0.69)°/s, (7.44±1.88)°/s, (20.04±5.53)°/s, respectively, without type IV wave. The intensity of SN was positively correlated with the asymmetric value of the gain of SPT left and right(r=0.450,P=0.002). That was, with the increase of SN strength, the asymmetric value also increased, and the worse the asymmetry of the gain of SPT left and right pursuit was, the worse the SPT waveform was. Conclusion: SPT gain, asymmetry and SPT waveforms are all affected by SN, and the greater the intensity of SN, the greater the influence on the three. When SN is strong, type III waves may occur, suggesting that acute peripheral vestibular syndrome can also affect the visual ocularmotor systems.

Abnormal Eye Movements in Parkinsonism and Movement Disorders

Abnormal eye movements are commonly observed in movement disorders. Ocular motility examination should include bedside evaluation and laboratory recording of ocular misalignment, involuntary eye movements, including nystagmus and saccadic intrusions/oscillations, triggered nystagmus, saccades, smooth pursuit (SP), and the vestibulo-ocular reflex. Patients with Parkinson's disease (PD) mostly show hypometric saccades, especially for the self-paced saccades, and impaired SP. Early vertical saccadic palsy is characteristic of progressive supranuclear palsy-Richardson's syndrome. Patients with cortico-basal syndrome typically show a delayed onset of saccades. Downbeat and gaze-evoked nystagmus and hypermetric saccades are characteristic ocular motor findings in ataxic disorders due to cerebellar dysfunction. In this review, we discuss various ocular motor findings in movement disorders, including PD and related disorders, ataxic syndromes, and hyperkinetic movement disorders. Systemic evaluation of the ocular motor functions may provide valuable information for early detection and monitoring of movement disorders, despite an overlap in the abnormal eye movements among different movement disorders.

Impaired Smooth Pursuit During Transient Global Amnesia

BACKGROUND AND PURPOSE: During transient global amnesia (TGA), selective impairment of episodic memory is assumed to occur due to alteration in the neuronal network between the hippocampus and parietooccipital cortices that also include a hub for smooth pursuit (SP) eye movements. This study aimed to determine whether SP is impaired during TGA, and to identify any anatomical and functional linkage present between the oculomotor and memory systems. METHODS: Within a median of 1.0 day of TGA, horizontal SP was evaluated in 145 patients with a target moving at peak velocities of 10°/s and 20°/s. The average SP gains of patients were compared with those of the age-matched controls. RESULTS: The patients with TGA showed lower SP gains in both directions for both peak target velocities. While the normal controls showed symmetric SP in the rightward and leftward directions, in the TGA patients the SP gain was lower during rightward than leftward SP regardless of bilaterality or the side of the lesions. CONCLUSIONS: The cortical regions processing information about visual motion appeared to be affected during or soon after an amnestic episode of TGA, and more so in the right hemisphere. This means that disturbed processing of dynamic visual information may be related to the impaired spatial orientation observed during TGA.

Two Cases of Myasthenia Gravis Showing Fatigibility Presenting with Decreased Gain of Smooth Pursuit / 대한평형의학회지

Myasthenia gravis (MG) is an autoimmune disease caused by autoantibodies to the acetylcholine receptors of the neuromuscular junction characterized by weakness and abnormal fatigability of the muscles. Therefore, the diagnosis of MG depends on the recognition of this distinctive pattern of fatigable weakness. Previous studies presented the diagnostic efficacy of saccadic eye movements in patients with ocular MG. We here in report 2 patients of ocular MG showing the fatigue effects during repetitive sustained smooth pursuit, and the effects of the administration of edrophonium on myasthenic smooth pursuit. Changes in smooth pursuits reflecting peripheral and secondary central mechanisms were demonstrated.

Abnormal Oculomotor Functions in Amyotrophic Lateral Sclerosis

BACKGROUND AND PURPOSE: Although traditionally regarded as spared, a range of oculomotor dysfunction has been recognized in amyotrophic lateral sclerosis (ALS) patients. ALS is nowadays considered as a neurodegenerative disorder of a third compartment comprising widespread areas of extra-motor brain including cerebellum. Our objective was to perform an observational study to examine for ocular motor dysfunction in patients with ALS and for any differences between bulbar-onset and spinal-onset patients. METHODS: Thirty two ALS patients (bulbar onset: 10, spinal onset: 22) underwent the standardized systemic evaluations using video-oculography. RESULTS: Oculomotor dysfunctions such as square wave jerks, saccadic dysmetria, abnormal cogwheeling smooth pursuits and head shaking and positional nystagmus of central origin have been observed in the ALS patients at a relatively early stage. Abnormal smooth pursuits and saccadic dysmetria were increased in the bulbar-onset compared to the spinal-onset (p < 0.05). CONCLUSIONS: These oculomotor abnormalities may be a marker of neuro-degeneration beyond motor neurons in ALS, especially in bulbar-onset disease. Future longitudinal studies of eye movement abnormalities have provided insights into the distribution and nature of the disease process.

Association Analysis between Chromogranin B Genetic Variations and Smooth Pursuit Eye Movement Abnormality in Korean Patients with Schizophrenia

OBJECTIVES: According to previous studies, the Chromogranin B (CHGB) gene could be an important candidate gene for schizophrenia which is located on chromosome 20p12.3. Some studies have linked the polymorphism in CHGB gene with the risk of schizophrenia. Meanwhile, smooth pursuit eye movement (SPEM) abnormality has been regarded as one of the most consistent endophenotype of schizophrenia. In this study, we investigated the association between the polymorphisms in CHGB gene and SPEM abnormality in Korean patients with schizophrenia. METHODS: We measured SPEM function in 24 Korean patients with schizophrenia (16 male, 8 female) and they were divided according to SPEM function into two groups, good and poor SPEM function groups. We also investigated genotypes of polymorphisms in CHGB gene in each group. A logistic regression analysis was performed to find the association between SPEM abnormality and the number of polymorphism. RESULTS: The natural logarithm value of signal/noise ratio (Ln S/N ratio) of good SPEM function group was 4.19 ± 0.19 and that of poor SPEM function group was 3.17 ± 0.65. In total, 15 single nucleotide polymorphisms of CHGB were identified and the genotypes were divided into C/C, C/R, and R/R. Statistical analysis revealed that two genetic variants (rs16991480, rs76791154) were associated with SPEM abnormality in schizophrenia (p = 0.004). CONCLUSIONS: Despite the limitations including a small number of samples and lack of functional study, our results suggest that genetic variants of CHGB may be associated with SPEM abnormality and provide useful preliminary information for further study.

Clinical significance of saccade test, smooth pursuit test, and optokinetic nystagmus test in nystagmography / 영남의대학술지

BACKGROUND: Saccade test, smooth pursuit test, and optokinetic nystagmus test are clinically useful tests to accurately diagnose vertigo. However, there have only been a few studies regarding a correlation between the anatomical site of the lesion and the abnormality of eyeball movement in patients with vertigo.METHODS: The medical records of 97 patients with vertigo between January 2006 and June 2008 were reviewed retrospectively. We classified many kinds of abnormalities regarding the saccade test, smooth pursuit test and optokinetic nystagmus test into several categories and analyzed the localizing lesion of vertigo.RESULTS: According to the saccade test, both total saccade abnormality (S-total) and slow velocity of saccade (S-type 3) were shown to be significantly higher in the central lesion of vertigo. According to the smooth pursuit test, symmetrical unidirectional smooth pursuit abnormality (SP-type 2) was observed to be significantly higher in the peripheral lesion over vertigo. Moreover, according to the optokinetic nystagmus test, total optokinetic nystagmus abnormalities (OKN-total) were shown to be significantly useful findings in the diagnosis of the central lesion of vertigo. The coexisting abnormalities of all three tests (S+SP+OKN abnormalities) were shown to be significantly higher in the central lesion of vertigo.CONCLUSION: These results suggest that all these tests, saccade test, smooth pursuit test, and optokinetic nystagmus test, are very useful to distinguish between the central lesion and the peripheral lesion of vertigo. However, these tests are not beneficial in localizing the central lesion of vertigo.

Clinical significance of saccade test, smooth pursuit test, and optokinetic nystagmus test in nystagmography / 영남의대학술지

BACKGROUND: Saccade test, smooth pursuit test, and optokinetic nystagmus test are clinically useful tests to accurately diagnose vertigo. However, there have only been a few studies regarding a correlation between the anatomical site of the lesion and the abnormality of eyeball movement in patients with vertigo. METHODS: The medical records of 97 patients with vertigo between January 2006 and June 2008 were reviewed retrospectively. We classified many kinds of abnormalities regarding the saccade test, smooth pursuit test and optokinetic nystagmus test into several categories and analyzed the localizing lesion of vertigo. RESULTS: According to the saccade test, both total saccade abnormality (S-total) and slow velocity of saccade (S-type 3) were shown to be significantly higher in the central lesion of vertigo. According to the smooth pursuit test, symmetrical unidirectional smooth pursuit abnormality (SP-type 2) was observed to be significantly higher in the peripheral lesion over vertigo. Moreover, according to the optokinetic nystagmus test, total optokinetic nystagmus abnormalities (OKN-total) were shown to be significantly useful findings in the diagnosis of the central lesion of vertigo. The coexisting abnormalities of all three tests (S+SP+OKN abnormalities) were shown to be significantly higher in the central lesion of vertigo. CONCLUSION: These results suggest that all these tests, saccade test, smooth pursuit test, and optokinetic nystagmus test, are very useful to distinguish between the central lesion and the peripheral lesion of vertigo. However, these tests are not beneficial in localizing the central lesion of vertigo.

Isolated Infarction of Anterior Cerebellar Vermis / 대한평형의학회지

The anterior cerebellar vermis has been known to act in coordination of gait and postural adjustment of the trunk and legs. However, oculomotor abnormalities in an isolated anterior vermian lesion have not been described in the literature. A 59-year-old man presented with acute non-rotatory dizziness and disequilibrium. Neuro-ophthalmologic examination found impaired smooth pursuit and hypometric saccades in the contralesional direction, and disconjugate ipsiversive ocular torsion, but without spontaneous or gaze-evoked nystagmus. Imaging study showed an infarction restricted to the rostral end of right cerebellar vermis involving the lingual and central lobules. The anterior cerebellar vermis participates in the maintenance of axial posture and gait, and also in the control of ocular motor and vestibular systems.

No Association between (AAT)n Repeat Polymorphisms in the Cannabinoid Receptor 1 Gene and Smooth Pursuit Eye Movement Abnormality in Korean Patients with Schizophrenia

OBJECTIVES: According to previous studies, the cannabinoid receptor 1 (CNR1) gene could be an important candidate gene for schizophrenia. Some studies have linked the (AAT)n trinucleotide repeat polymorphism in CNR1 gene with the risk of schizophrenia. Meanwhile, smooth pursuit eye movement (SPEM) has been regarded as one of the most consistent endophenotypes of schizophrenia. In this study, we investigated the association between the (AAT)n trinucleotide repeats in CNR1 gene and SPEM abnormality in Korean patients with schizophrenia. METHODS: We measured SPEM function in 167 Korean patients with schizophrenia (84 male, 83 female) and they were divided according to SPEM function into two groups, good and poor SPEM function groups. We also investigated allele frequencies of (AAT)n repeat polymorphisms on CNR1 gene in each group. A logistic regression analysis was performed to find the association between SPEM abnormality and the number of (AAT)n trinucleotide repeats. RESULTS: The natural logarithm value of signal/noise ratio (Ln S/N ratio) of the good SPEM function group was 4.34 ± 0.29 and that of the poor SPEM function group was 3.21 ± 0.70. In total, 7 types of trinucleotide repeats were identified, each containing 7, 10, 11, 12, 13, 14, and 15 repeats, respectively. In the patients with (AAT)₇ allele, the distributions of the good and poor SPEM function groups were 18 (11.1%) and 19 (11.0%) respectively. In the patients with (AAT)₁₀ allele, (AAT)₁₁ allele, (AAT)₁₂ allele, (AAT)₁₃ allele, (AAT)₁₄ allele and (AAT)₁₅ allele, the distributions of good and poor SPEM function groups were 13 (8.0%) and 12 (7.0%), 4 (2.5%) and 6 (3.5%), 31 (19.8%) and 35 (20.3%), 51 (31.5%) and 51 (29.7%), 36 (22.2%) and 45 (26.2%), 9 (5.6%) and 4 (2.3%) respectively. As the number of (AAT) n repeat increased, there was no aggravation of abnormality of SPEM function. CONCLUSIONS: There was no significant aggravation of SPEM abnormality along with the increase of number of (AAT)n trinucleotide repeats in the CNR1 gene in Korean patients with schizophrenia.

Eye Movement Abnormalities and Neuroimaging Findings of Disequilibrium of Unknown Origin / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Although disequilibrium is common type of dizziness in older people, it is sometimes difficult to identify a specific cause for this problem. The diffuse brain pathology including subcortical ischemia and atrophy can be a cause for patients with disequilibrium of unknown cause. Aim of this study is to identify the eye movements and neuroimaging features in patients with disequilibrium. MATERIALS AND METHODS: We performed a prospective investigation in patients with disequilibrium of unknown cause. We collected information on demographic characteristics and clinical features of disequilibrium. The impact of dizziness on everyday life was assessed by 25-item dizziness handicap inventory (DHI). Vestibular function test (VFT) includes smooth pursuit, saccade, optokinetic nystagmus, and rotatory chair test. Subcortical white matter lesions and brain atrophy were graded from brain magnetic resonance image (MRI). RESULTS: This study included 14 patients (12 female and 2 male), aged between 64 and 84 years, mean age 74.01+/-6.02 years. The score of DHI was 39.4+/-11.8 (20-58). Eye movements were abnormal in 13 patients and normal in only one patient. The degree of subcortical ischemia was mild in 7, moderate in 4, and severe in 3 patients. Ventricular brain ratio was 0.23+/-0.03. However, there was no significant relationship between MRI findings and the degree of oculomotor alterations (result of VFT). CONCLUSION: Patients with disequilibrium of unknown cause are usually elderly women. Alterations in oculomotor movements and diffuse brain pathology including white matter lesions and atrophy were observed in patients with disequilibrium of unknown cause.

Initiation of Smooth Pursuit in Acute Cerebellar Infarction: A Preliminary Study / 대한평형의학회지

BACKGROUND AND OBJECTIVES: The cerebellar lesion causes an initiation deficit of smooth-pursuit eye movement depending on the location of the lesion. We investigated the initiation of smooth pursuit in patients with cerebellar infarction and in healthy subjects, using step-ramp stimuli. MATERIALS AND METHODS: Ten patients with cerebellar infarction documented by brain magnetic resonance imaging and fifty healthy subjects are recruited. To estimate the initiation of smooth pursuit, the onset latency and initial acceleration during the first 100ms of the horizontal smooth pursuit were estimated using the step-ramp target stimuli (5degrees/sec, 10degrees/sec, and 20degrees/sec). RESULTS: In healthy subjects, onset latency of pursuit was shortened and initial acceleration was increased as target velocity was increasing. In patients with unilateral cerebellar infarction, the onset latency of ipsilesional smooth pursuit was significantly delayed at the target velocities of 10degrees/sec and 20degrees/sec. For the fast target velocity of 20degrees/sec, there was significant decrease of the initial acceleration of contralesional pursuit. CONCLUSION: In comparison with the healthy subjects, the patients with unilateral cerebellar lesions showed significant delay of pursuit onset and decrease of initial eye acceleration in the fast target velocity. These results support that the cerebellar lesions affect not only steady-state smooth pursuit gain but also the processing time required to initiate smooth pursuit, i.e., onset latency and initial acceleration. More extensive study is needed to confirm the role of cerebellum for parametric adjustment of each component of smooth pursuit.

Maduración visual retardada / Delayed visual maturation

Retraso en la maduración visual es el término utilizado para describir aquellos niños con incapacidad de fijar o seguir objetos en el ambiente, que no responden ante la proximidad de un objeto amenazante o un destello de luz, por ejemplo, abrir y cerrar los ojos; pero luego mejora a la edad de 6 meses sin tratamiento. Se incluyen dentro de las posibles causas la falta de oxígeno antes, durante o después del nacimiento, enfermedades producidas por virus o bacterias como la meningitis y el citomegalovirus, o una lesión traumática, aunque hoy en día queda poco consenso en cuanto a la etiología de este fenómeno. Estos niños con retraso en la maduración visual parecen ciegos, incapaces de centrar la atención, fijar o seguir cualquier parte del mundo visual. La exploración ocular y neurológica del niño es completamente normal. Los síntomas se resuelven sin tratamiento y con frecuencia, no se encuentra ninguna causa para la presentación inicial. El retraso en la maduración visual se clasifica en 3 grupos: el primero con retraso en la maduración visual como única anomalía y una recuperación rápida y completa. El segundo incluye aquellos casos con problemas oculares, como estrabismo, error refractivo elevado, retraso mental, entre otros, logrando una recuperación más lenta y a menudo incompleta. El tercer grupo incluye los casos con otras anomalías oculares

Delayed visual maturation is the term used to describe those children with inability to fix their eyes with the object or to visually follow them in the environment, who do not react to a threatening object or a gleam of light close to them, for example, by opening and closing their eyes. However, they generally improve their condition at the age of 6 months without any treatment. The possible causes of this disorder may be lack of oxygen, before, during or after birth, illnesses caused by viruses or bacteria, such as meningitis and cytomegalovirus, or a traumatic lesion, although there exists now minority consensus about the real etiology of this phenomenon. The children suffering delayed visual maturation seem to be blind, unable to focus attention, fix or visually follow any portion of the visual world. Ocular and neurological examination of the child is completely normal. Symptoms disappear without any treatment and the cause for the initial occurrence is usually unfound. The delayed visual maturation is classified into 3 groups, the first group with delayed visual maturation as the only anomaly and a quick and complete recovery. The second group includes those cases with ocular problems, namely strabismus, high refractive error, mental retardation, and others, in which recovery is slower and often incomplete. The third group includes cases with other ocular anomalies

Bedside Evaluation of Dizzy Patients

In recent decades there has been marked progress in the imaging and laboratory evaluation of dizzy patients. However, detailed history taking and comprehensive bedside neurotological evaluation remain crucial for a diagnosis of dizziness. Bedside neurotological evaluation should include examinations for ocular alignment, spontaneous and gaze-evoked nystagmus, the vestibulo-ocular reflex, saccades, smooth pursuit, and balance. In patients with acute spontaneous vertigo, negative head impulse test, direction-changing nystagmus, and skew deviation mostly indicate central vestibular disorders. In contrast, patients with unilateral peripheral deafferentation invariably have a positive head impulse test and mixed horizontal-torsional nystagmus beating away from the lesion side. Since suppression by visual fixation is the rule in peripheral nystagmus and is frequent even in central nystagmus, removal of visual fixation using Frenzel glasses is required for the proper evaluation of central as well as peripheral nystagmus. Head-shaking, cranial vibration, hyperventilation, pressure to the external auditory canal, and loud sounds may disclose underlying vestibular dysfunction by inducing nystagmus or modulating the spontaneous nystagmus. In patients with positional vertigo, the diagnosis can be made by determining patterns of the nystagmus induced during various positional maneuvers that include straight head hanging, the Dix-Hallpike maneuver, supine head roll, and head turning and bending while sitting. Abnormal smooth pursuit and saccades, and severe imbalance also indicate central pathologies. Physicians should be familiar with bedside neurotological examinations and be aware of the clinical implications of the findings when evaluating dizzy patients.

The analysis of smooth pursuit test in unilateral vestibular peripheral vertigo / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To analyze the result of smooth pursuit test (SPT) in unilateral vestibular peripheral vertigo and investigate its influencing factors.@*METHOD@#Smooth pursuit test (SPT) and spontaneous nystagmus (SN) were examined in one hundred and eighty-five patients with unilateral peripheral vertigo (case group) and 51 normal persons (control group) by Video-Nystagmography (Synapsis, France), and the gain of SPT and SN were selected as the observation parameters in order to analyze the waveform and gain of SPT and the relativity between SN and the gain of SPT.@*RESULT@#Of the 185 patients, 105 (56.8%), 72 (38.9%) and 8 (4.3%) cases produced I , II and III waveforms respectively. Of these patients, 58 (31.4%) demonstrated SN and none had IV waveform. While of 51 normal persons, 38 (74.5%), 13 (25.5%) persons produced I and II waveforms respectively and there were no III, IV waveforms or SN. There was statistical significance between the strong and weak gain of SPT in these two groups. Weak gain was significantly different between two groups. The strong and weak gain of SPT in case group were 0.86 +/- 0.06, 0.80 +/- 0.06; 0.78 +/- 0.09, 0.65 +/- 0.1; 0.68 +/- 0.13, 0.45 +/- 0.12. The relativity between SN and the gain of SPT was positive when they had same direction (r(s) = -0.63, P<0.05) and negative when opposite (r(s) = 0.34, P<0.05).@*CONCLUSION@#I , II, III three waveforms of SPT could appear in unilateral vestibular peripheral vertigo and the corresponding gains are gradually decreasing. SN is the influencing factor of SPT.

Congenital Ocular Motor Apraxia: Clinico-Radiological Analyses

BACKGROUND: Congenital ocular motor apraxia (COMA) is characterized by impaired voluntary saccades and abnormal head thrusts. However, mechanism of this disorder remains to be elucidated. METHODS: This study analyzed the eye movements and imaging findings in 16 patients with COMA, who had been recruited from 2003 to 2009 at the Neuro-Ophthalmology Clinic of Seoul National University Bundang Hospital. RESULTS: All the children showed impaired saccades and smooth pursuit in the horizontal direction. One of them also exhibited impaired vertical saccades and smooth pursuit. Eight children showed excessive blinks in association with an attempt to generate saccades. The typical head thrust usually developed around the age of eight months and had resolved by the age of 6-7 years. History of spasmus nutans was confirmed in seven children. Fourteen children showed cerebellar vermian hypoplasia, mostly in the inferior portion, and five of them also had dysgenesis of the corpus callosum. The severity of cerebellar vermian hypoplasia was correlated with developmental delay, as determined by the age of independent walking. CONCLUSION: Cerebellar vermian hypoplasia is a frequent finding in COMA. Dysfunction of the oculomotor vermis may responsible for the impaired saccades and smooth pursuit in COMA. The occasional association of COMA with spasmus nutans indicates a common pathophysiology of these benign developmental disorders.

Cerebellar Hypoperfusion during Transient Global Amnesia: An MRI and Oculographic Study

BACKGROUND AND PURPOSE: Transient global amnesia (TGA) is characterized by sudden anterograde and retrograde amnesia lasting for up to 24 hours. Diffusion-weighted magnetic resonance imaging (DWI) in cases of TGA and ischemia demonstrates a high frequency of high signal intensities restricted to the hippocampus, and this has been proposed as an etiology of TGA. The aims of this study were to characterize the DWI and single-photon-emission computed tomography (SPECT) findings during the acute and recovered phases of TGA and to correlate the findings with oculomotor abnormalities. METHODS: Five consecutive patients with a clinical diagnosis of TGA underwent DWI and SPECT of the brain within 24 hours after symptom onset and again 3 days later. Eye movements were also recorded using three-dimensional video-oculography. RESULTS: In all patients, DWI disclosed small punctuate (1-3 mm), high-signal lesions in the lateral portion of the hippocampus. The initial SPECT also revealed hypoperfusion in the cerebellar vermis, which had recovered by the follow-up examination. Three patients showed saccadic hypermetria or impaired smooth pursuit only during the acute phase. CONCLUSIONS: Our patients with TGA showed cerebellar vermian hypoperfusion in addition to ischemic insults to the lateral hippocampus. The oculomotor abnormalities observed in our patients support the occurrence of cerebellar dysfunction during the TGA attack.

No Association between Val108/158Met Polymorphism on Catechol-O-Methyl Transferase(COMT) Gene and Smooth Pursuit Eye Movement(SPEM) Abnormality in Korean Schizophrenia Patients

OBJECTIVES: We investigated the association of Val108/158Met polymorphism on catechol-O-methyl transferase(COMT) gene with smooth pursuit eye movement(SPEM) abnormality in Korean schizophrenia patients. METHODS: We measured SPEM in 217 Korean schizophrenia patients(male 116, female 101) and divided them into two groups, one was a good SPEM function group and the other was a poor SPEM function group. Then we analyzed Val108/158Met polymorphism on COMT gene. We compared the differences of genotype and allele distributions of the polymorphism on COMT gene between the two groups. RESULTS: The natural logarithm value of signal/noise ratio(Ln S/N ratio) of the good SPEM function group was 4.39+/-0.33(mean+/-s.d.) and that of poor SPEM function group was 3.17+/-0.71. There were no statistically significant differences of age and male/female ratio between the two groups. There were no significant differences of genotype or allele distributions of the Val108/158Met polymorphism on COMT gene between the two schizophrenic groups. CONCLUSIONS: The results suggest that Val108/158Met polymorphism on COMT gene is not related to SPEM function abnormality in schizophrenia.

Clinical and Oculographic Findings of X-linked Congenital Nystagmus in Three Korean Families

BACKGROUND AND PURPOSE: Congenital nystagmus (CN) is an ocular oscillation that usually manifests during early infancy. Typical features of CN include bilateral, conjugate, uniplanar, and usually horizontal eye movements, a null position, increased oscillation during fixation, and decreased amplitude during convergence. Our purposes were description and analysis of clinical and oculomotor findings of patients with X-linked familial CN. METHODS: We describe the clinical and oculographic features of five patients from three families with X-linked CN. Three-dimensional video-oculography disclosed various patterns of CN and variable degrees of gaze-holding deficits and visual impairments. RESULTS: The features of CN varied even in patients from the same family. Head tilt, strabismus, reversal of optokinetic nystagmus, and impairments of the vestibulo-ocular reflex, smooth pursuits, and saccades were frequent findings. CONCLUSIONS: The intra- and interfamilial diversities imply that heredity plays a secondary role in determining the clinical phenotypes and waveforms of CN.

Clinical and Oculographic Findings of X-linked Congenital Nystagmus in Three Korean Families

BACKGROUND AND PURPOSE: Congenital nystagmus (CN) is an ocular oscillation that usually manifests during early infancy. Typical features of CN include bilateral, conjugate, uniplanar, and usually horizontal eye movements, a null position, increased oscillation during fixation, and decreased amplitude during convergence. Our purposes were description and analysis of clinical and oculomotor findings of patients with X-linked familial CN. METHODS: We describe the clinical and oculographic features of five patients from three families with X-linked CN. Three-dimensional video-oculography disclosed various patterns of CN and variable degrees of gaze-holding deficits and visual impairments. RESULTS: The features of CN varied even in patients from the same family. Head tilt, strabismus, reversal of optokinetic nystagmus, and impairments of the vestibulo-ocular reflex, smooth pursuits, and saccades were frequent findings. CONCLUSIONS: The intra- and interfamilial diversities imply that heredity plays a secondary role in determining the clinical phenotypes and waveforms of CN.