Sympathetic contralateral vestibulopathy after unilateral zoster oticus.
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A unique case of initially right sided varicella zoster induced Ramsay-Hunt syndrome with complete vestibular loss is reported. The patient subsequently developed deficits of the left vestibule 5 months later. An autoimmune pathogenesis of the left vestibular failure rather than bilateral varicella zoster infection was suggested by the following data: (1) no evidence of vesicular eruptions on the left auricle and the virtual absence of antiviral antibodies after onset of bilateral vestibulopathy; (2) prompt response of the left vestibule to immunosuppressive therapy with corticosteroids; and (3) presence of atypical nervous tissue specific autoantibodies against a 45 kDa protein. (+info)
Postequatorial horizontal rectus recession in the management of congenital nystagmus.
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Postequatorial (12 mm) recession of all four horizontal recti was done in nine patients with congenital nystagmus. Fifteen of 18 eyes showed decreased amplitude of nystagmus while 12 eyes also showed an increase in visual acuity. Functionally, significant limitation of ocular motility was not encountered despite unconventionally large recessions. (+info)
Arnold-Chiari malformation and nystagmus of skew.
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The Arnold-Chiari malfomation is typically associated with downbeat nystagmus. Eye movement recordings in two patients with Arnold-Chiari malfomation type 1 showed, in addition to downbeat and gaze evoked nystagmus, intermittent nystagmus of skew. To date this finding has not been reported in association with Arnold-Chiari malfomation. Nystagmus of skew should raise the suspicion of Arnold-Chiari malfomation and prompt sagittal head MRI examination. (+info)
Cross-axis adaptation of pursuit initiation in humans.
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PURPOSE: The initial acceleration of pursuit in the open-loop period is under adaptive control and undergoes motor learning. The current study was undertaken to examine the hypothesis that the direction of pursuit initiation can also be adaptively modified. METHODS: Four neurologically and ophthalmologically normal subjects participated in the experiment. A modified step-ramp paradigm was used to induce cross-axis adaptation, in which a ramp target changed its direction orthogonally just after the target crossed the center. Four direction changes were tested in separate experiments: left to up, left to down, down to left, and up to left. During a 30-minute adaptation session, the target moved in one of two randomly chosen directions (right to left or up to down) at one of two randomly chosen speeds (15.6 or 22.3 deg/sec), but the target changed orthogonally in only one direction. A linear regression fit to the initial 100-msec segment of the pursuit trace was used to determine the direction of pursuit initiation. RESULTS: In all cases, an adaptive change in pursuit initiation was gradually induced in the direction called for by the training paradigm. Adaptation was usually completed (90 degrees shift) within the 30-minute training session but declined quickly to an approximate 30 degrees -shift after training. The latency and vectorial amplitude of the initial acceleration remained unchanged. The adaptation was specific for the direction but not the velocity of the target. CONCLUSIONS: This study showed that the direction of pursuit initiation is under adaptive control, as has been shown for saccadic eye movements and the vestibulo-ocular reflex. (+info)
Vestibular dysfunction in familial dysautonomia. The Riley-Day syndrome.
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We report the bilateral absence of response to tests of vestibular function in 5 patients with familial dysautonomia. (+info)
Blast injury of the ear in a confined space explosion: auditory and vestibular evaluation.
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BACKGROUND: The ear is the most frequent organ affected during an explosion. Recognition of possible damage to its auditory and vestibular components, and particularly the recovery time of the incurred damage, may help in planning the optimal treatment strategies for the otologic manifestations of blast injury and preventing deleterious consequences. OBJECTIVE: To report the results of the oto-vestibular initial evaluation and follow-up of 17 survivors of a suicide terrorist attack on a municipal bus. METHODS: These 17 patients underwent periodic ear inspections and pure tone audiometry for 6 months. Balance studies, consisting of electronystagmography and computerized dynamic posturography were performed at the first time possible. RESULTS: Complaints of earache, aural fullness and tinnitus resolved, whereas dizziness persisted in most of the patients. By the end of the follow-up, 15 (55.6%) of the eardrum perforations had healed spontaneously. Hearing impairment was detected in 33 of the 34 tested ears. Recovery of hearing was complete in 6 ears and partial in another 11. ENG and CDP were performed in 13 patients: 5 had abnormal results on CDP while the ENG was normal in all the patients. Of the seven patients who complained of vertigo, only one improved and was free of symptoms 1 month after the explosion. CONCLUSION: Exposure to a high powered explosion in a confined space may result in severe auditory and vestibular damage. Awareness of these possible ear injuries may prevent many of the deleterious consequences of such injuries. (+info)
Motor and sensory characteristics of infantile nystagmus.
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BACKGROUND/AIMS: Past studies have explored some of the associations between particular motor and sensory characteristics and specific categories of non-neurological infantile nystagmus. The purpose of this case study is to extend this body of work significantly by describing the trends and associations found in a database of 224 subjects who have undergone extensive clinical and psychophysical evaluations. METHODS: The records of 224 subjects with infantile nystagmus were examined, where 62% were idiopaths, 28% albinos, and 10% exhibited ocular anomalies. Recorded variables included age, mode of inheritance, birth history, nystagmus presentation, direction of the nystagmus, waveform types, spatial and temporal null zones, head postures and nodding, convergence, foveation, ocular alignment, refractive error, visual acuity, stereoacuity, and oscillopsia. RESULTS: The age distribution of the 224 patients was between 1 month and 71 years, with the mean age and mode being 23 (SD 16) years and 16-20 years respectively. By far the most common pattern of inheritance was found to be autosomal dominant (n = 40), with the nystagmus being observed by the age of 6 months in 87% of the sample (n = 128). 139 (62%) of the 224 subjects were classified as idiopaths, 63 (28%) as albinos, and 22 (10%) exhibited ocular anomalies. Conjugate uniplanar horizontal oscillations were found in 174 (77.7%) of the sample. 32 (14.3%) had a torsional component to their nystagmus. 182 (81.2%) were classed as congenital nystagmus (CN), 32 (14.3%) as manifest latent nystagmus (MLN), and 10 (4.5%) as a CN/MLN hybrid. Neither CN nor MLN waveforms were related to any of the three subject groups (idiopaths, albinos, and ocular anomalies) MLN was found in idiopaths and albinos, but most frequently in the ocular anomaly group. The most common oscillation was a horizontal jerk with extended foveation (n = 49; 27%). The amplitudes and frequencies of the nystagmus ranged between 0.3-15.7 degrees and 0.5-8 Hz, respectively. Periodic alternating nystagmus is commonly found in albinos. Albino subjects did not show a statistically significantly higher nystagmus intensity when compared with the idiopaths (p>0.01). 105 of 143 subjects (73%) had spatial nulls within plus or minus 10 degrees of the primary position although 98 subjects (69%) employed a compensatory head posture. Subjects with spatial null zones at or beyond plus or minus 20 degrees always adopted constant head postures. Head nodding was found in 38 subjects (27% of the sample). Horizontal tropias were very common (133 out of 213; 62.4%) and all but one of the 32 subjects with MLN exhibited a squint. Adult visual acuity is strongly related to the duration and accuracy of the foveation period. Visual acuity and stereoacuity were significantly better (p<0.01) in the idiopaths compared to the albino and ocular anomaly groups. 66 subjects out of a sample of 168 (39%) indicated that they had experienced oscillopsia at some time. CONCLUSIONS: There are strong ocular motor and sensory patterns and associations that can help define an infantile nystagmus. These include the nystagmus being bilateral, conjugate, horizontal uniplanar, and having an accelerating slow phase (that is, CN). Decelerating slow phases (that is, MLN) are frequently associated with strabismus and early form deprivation. Waveform shape (CN or MLN) is not pathognomonic of any of the three subject groups (idiopaths, albinos, or ocular anomalies). There is no one single stand alone ocular motor characteristic that can differentiate a benign form of infantile nystagmus (CN, MLN) from a neurological one. Rather, the clinician must consider a host of clinical features. (+info)
Diagnostic value of nystagmus: spontaneous and induced ocular oscillations.
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Research over the past 20 years has provided a clearer understanding of the pathogenesis of most forms of nystagmus and other ocular oscillations. To the clinician, these advances translate into greater accuracy of nystagmus as a diagnostic sign. However, to capitalise on these advances, it is important to systematically examine eye movements and interpret the findings with reference to pathophysiology. In this review we describe a scheme for examining the patient with nystagmus and interpreting common ocular oscillations; some examples are provided as video clips. (+info)