1/154. Disorders in cerebellar ocular motor control. II. Macrosaccadic oscillation. An oculographic, control system and clinico-anatomical analysis.A distinctive cerebellar ocular motor disorder, macrosaccadic oscillation, evolved simultaneously with an acute cerebellar syndrome in 4 patients, 2 with haemorrhagic metastatic melanoma deep in the vermis, a third with a presumed cerebellar haematoma and a fourth with focal demyelinating disease. Ocular oscillations were conjugate, horizontal, symmetrical, occurred in bursts of several seconds duration, had amplitudes of 30 degrees to 50 degrees, and were evoked whenever the patient attempted to shift visual fixation or pursue a moving target. Photo-electric recordings in one patient with tumour defined features of this disorder of saccadic eye movement: (i) oscillation was composed of saccades, (ii) frequency was 2 Hz, (iii) bursts occurred with amplitude first increasing and then decreasing, (iv) intervals between beginnings of saccades averaged 260 ms and (v) eye position did not exhibit systematic drift during the intersaccadic period. These features documented the inreased gain and instability of the visually guided saccadic system. By using increased feed-forward gain in a sampled-data control model we simulated the pattern of macrosaccadic oscillation. We belive that the acute loss of the calibrator function of the cerebellum accounts for the gain abnormality underlying macrosaccadic oscillation.- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
2/154. Acquired convergence-evoked pendular nystagmus in multiple sclerosis.Nystagmus seen only with convergence is unusual. We describe four cases of acquired convergence-evoked pendular nystagmus in patients with multiple sclerosis. The nystagmus was horizontal and asymmetric in all patients. Eye movement recordings in one subject showed a conjugate rather than a convergent-divergent relationship of the phase of movement between the two eyes. All patients had evidence of optic neuropathy and cerebellar dysfunction. Occlusion of either eye during fixation of near targets led to divergent drift of the covered eye and a decrease in nystagmus. Intravenous scopolamine reduced nystagmus in one patient. Base-in prisms alleviated symptoms of oscillopsia at near and improving reading visual acuity. Convergence-evoked pendular nystagmus may be more common than currently appreciated, particularly among patients with multiple sclerosis.- - - - - - - - - - ranking = 0.5keywords = visual (Clic here for more details about this article) |
3/154. Oscillopsia and pseudonystagmus in kidney transplant patients.PURPOSE: Modern immunosuppressants have improved the success of kidney transplantation for renal failure patients. They also may induce neurotoxic effects including tremor. We report two cases of pseudonystagmus and oscillopsia in transplant patients caused by immunosuppressant-induced head tremor and gentamicin-induced vestibulotoxicity. methods: case reports. head tremor, static visual acuity, and dynamic visual acuity were measured. Vestibular function was evaluated with ice water calorics. RESULTS: Both patients had significant head tremor and pseudonystagmus. head stabilization improved static visual acuity. Dynamic visual acuity revealed a 4-line and 10-line loss of visual acuity, respectively. CONCLUSIONS: These findings of pseudonystagmus and oscillopsia are likely to become more prevalent as more renal failure patients receive transplants. Improvement may be seen with reduction of immunosuppressant, reduction of stimulant intake, use of medications to reduce head tremor, and vestibular rehabilitation.- - - - - - - - - - ranking = 2.5keywords = visual (Clic here for more details about this article) |
4/154. Nystagmus mimicking spasmus nutans as the presenting sign of bardet-biedl syndrome.PURPOSE: To investigate the nystagmus of twin brothers presenting with spasmus nutans later diagnosed as bardet-biedl syndrome. methods: The twins presented at the age of 14 months with a presumed diagnosis of spasmus nutans. They were followed clinically and with quantitative electro-oculographic eye movement recordings until the age of 6 years. RESULTS: polydactyly, truncal obesity, mild delay in cognitive development, visual acuity of 20/100, attenuated retinal vessels and pale disks, and bilaterally almost extinguished scotopic and photopic electroretinograms were found in both brothers. They had fine, fast, pendular, disconjugate, intermittent, oblique nystagmus. No head nodding was observed. CONCLUSION: As described in patients with other retinal diseases such as achromatopsia and congenital stationary night blindness, nystagmus of patients with bardet-biedl syndrome can mimic spasmus nutans.- - - - - - - - - - ranking = 0.5keywords = visual (Clic here for more details about this article) |
5/154. Periodic alternating nystagmus and congenital nystagmus: similarities in possibly inherited cases.In this paper, 2 patients, a daughter with periodic alternating nystagmus and a mother with congenital fixation nystagmus, are presented, and the similarities of the two disorders are discussed, not only in the eye movements, but also in their underlying abnormalities. The literature was reviewed, and the link between periodic alternating and congenital fixation nystagmus, which had been suggested based on circumstantial evidence, may be confirmed by our cases. The possible evidence of inheritance suggests that the two disorders share common abnormalities in visual processing.- - - - - - - - - - ranking = 0.5keywords = visual (Clic here for more details about this article) |
6/154. Acquired pendular nystagmus with voluntary inhibition.This report documents a case of voluntary inhibition of acquired pendular nystagmus after head trauma. A 30-year-old male developed oscillopsia and decreased visual acuity, as well as findings of acquired pendular nystagmus with voluntary inhibition after head trauma. The EOG finding was horizontal 18-20 Hz bilateral symmetrical pendular nystagmus in all directions of gaze at near and distant fixation. Nystagmus did not change with 14 Prism Diopter base-out prisms on both eyes, but it was possible to abolish it intentionally. baclofen and clonazepam had no effect in improving the patient's symptoms and EOG finding.- - - - - - - - - - ranking = 0.5keywords = visual (Clic here for more details about this article) |
7/154. Two types of foveation strategy in 'latent' nystagmus: fixation, visual acuity and stability.The authors studied the foveation dynamics of two individuals with latent/manifest latent nystagmus (LMLN) to test the hypothesis that oscillopsia suppression and good visual acuity require periods of accurate target foveation at low slip velocities. Congenital nystagmus (CN) waveforms contain post-saccadic foveation periods; the LMLN waveform does not and yet allows for both oscillopsia suppression and good acuity. During fixation with both eyes open, there were intervals when the eyes were still and correctly aligned; at other times, there was esotropia and nystagmus with slow-phase velocities less than /- 4 deg/sec and each fast phase pointed the fovea of the fixating eye at the target. However, cover of either eye produced LN and a different strategy was employed: the fast phases carried the fixating eye past the target and the fovea subsequently reacquired it during the slowest parts of the slow phases. The authors confirmed this in both subjects, whose high acuities were made possible by foveation occuring during the low-velocity portions of their slow phases. A nystagmus foveation function (NFF), originally developed for CN, was calculated for both LN and MLN intervals of fixation and it was found to track visual acuity less accurately for individuals with high acuity. Individuals with LMLN exhibit two different foveation strategies: during low-amplitude LMLN, the target is foveated immediately after the fast phases; and during high-amplitude LMLN, target foveation occurs towards the end of the slow phases. Therefore, the saccadic system can be used to create retinal error rather than eliminate it if this strategy is beneficial. Individuals with LMLN foveated targets with the same eye-position and -velocity accuracy as those with CN and the NFF provides a rough estimate of acuity in both. Current calibration methods for both infrared and search-coil techniques need to be altered for subjects with LMLN.- - - - - - - - - - ranking = 3keywords = visual (Clic here for more details about this article) |
8/154. Epileptic nystagmus: a case study video-EEG correlation.Epileptic nystagmus (EN) is an uncommon phenomenon characterized by repetitive and rapid saccades, in association with epileptic discharges. We present a critical video-EEG recording in a patient with occipital seizures that appeared clinically as EN. The subject, male, 70 years-old, was examined because of generalized tonic-clonic seizures, preceded by left cephalic version. These were controlled using i.v. PHT, but partial seizures persisted, which we recorded using video-EEG. Clinically, we observed episodes of left conjugate deviation of the eyes, accompanied by horizontal nystagmoid movements, with a rapid leftward component and visual hallucinations. The patient did not lose consciousness. Ictal EEG: spike rhythm in the posterior right occipito-temporal region extending to adjacent and contralateral regions, followed by post-discharge of slow waves. The video-EEG was interpreted as partial oculo-clonic status epilepticus of right temporo-occipital origin. Cranial MRI: old, bilateral hemorrhaging occipital contusions associated with previous cranial injury. The picture persisted for two days, and disappeared with administration of CBZ 600 mg/d. Our patient's nystagmus seemed to be related to the critical activity recorded in the right occipito-temporal region. The co-existence of visual hallucinations and the video-EEG correlation support this possibility. This phenomenon is probably due to epileptic activation of the cortical center of saccadic movements, with a rapid phase of nystagmus, contralateral to the focus, and a slow ipsilateral phase in association with a defect in the gaze-fixing system ("leaky neural integrator") [published with videosequences].- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
9/154. Combined pharmacologic and surgical approach to acquired nystagmus due to multiple sclerosis.PURPOSE: To describe a combined pharmacological and surgical approach to treating acquired nystagmus in a patient with multiple sclerosis. DESIGN: Interventional case report. methods: A 40-year-old patient with acquired horizontal and vertical nystagmus and severe oscillopsia secondary to multiple sclerosis had combined treatment with gabapentin and a vertical Kestenbaum-type procedure. RESULTS: After gabapentin treatment (3,000 mg orally daily) the horizontal nystagmus was significantly reduced, and the patient developed a marked chin-up position. The vertical nystagmus remained unchanged, dampening on downgaze. A recession of both inferior rectus muscles reduced the nystagmus significantly in primary position, the abnormal head position disappeared, and oscillopsia completely resolved. Treatment increased visual acuity from 6/24 in the right eye and 6/60 in the left eye to 6/9 in both eyes. CONCLUSIONS: Acquired nystagmus in multiple sclerosis can be significantly improved by using a combined pharmacological and surgical approach.- - - - - - - - - - ranking = 0.5keywords = visual (Clic here for more details about this article) |
10/154. Improvement of acquired pendular nystagmus by gabapentin: case report.Acquired Pendular Nystagmus (APN) may cause distressing visual symptoms in patients who are already suffering a severe general disease. Averbuch-Heller et al. conducted the first double-blind controlled study on treatment for APN. They showed that gabapentin substantially reduces pendular nystagmus and significantly increases visual acuity in the majority of patients. We present a patient with APN due to multiple sclerosis who suffered severe oscillopsy and reduction of visual acuity and who substantially benefited from a trial treatment with this agent.- - - - - - - - - - ranking = 1.5keywords = visual (Clic here for more details about this article) |
| | Next -> |