Different types of intra-saccadic slowing in congenital (RAPSN-mutation) and acquired myasthenic syndromes.
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Adult↗
Biomedical subjects
W Heide
Publications and source records attributed to W Heide.
Three-dimensional cytoarchitectonic analysis of the posterior bank of the human precentral sulcus.
Studies employing functional magnetic resonance imaging have identified the human frontal eye field as being in the anterior and partly in the posterior wall, as well as at the base of the precentral sulcus. Moreover, it is known that the frontal eye field extends rostrally to the superior frontal sulcus. According to Brodmann's cytoarchitectonic map, this region belongs to the dysgranular Brodmann area 6 of the premotor cortex. However, the frontal eye field in non-human primates has been located within the arcuate sulcus in Brodmann area 8, generating considerable debate about where to locate exactly the frontal eye field in humans. Functional studies of the primate frontal eye field have revealed a principal homology of voluntary saccadic control systems in human and old-world monkeys, especially the macaque. But these homologies seem to be contradicted by the reported topographic localization at the cytoarchitectonic level. Therefore, we studied the cytoarchitectonic structure of the posterior bank of the precentral sulcus of a human brain, employing newly developed spatial mapping techniques to provide data about whether or not this region should be considered cytoarchitecturally homogeneous or heterogeneous. We used functional magnetic resonance imaging results, as an initial guide in localizing a region which is activated by saccadic tasks. A maximum of activation was detected around the junction of the superior frontal sulcus and the precentral sulcus extending 1.5 cm along the precentral sulcus in direction of the lateral sulcus. Here, one human brain has been analyzed to obtain preliminary data about the cytoarchitectonical changes of a part of area 6. Statistical analysis of the three-dimensional architectonic data from this region allowed us to identify a zone at the posterior bank, which in other studies has been associated with a functional region that controls pursuit eye movements and performs sensory-to-motor transformations. We found two significant sectors along the ventral part of the posterior bank of the precentral sulcus. The caudal transition region coincides partly with a region that integrates retinal and eye position signals for target location, arm, and axial movements. The second more ventrally located region is attributed to process oral-facial movements. The caudal transition region coincides with our functional magnetic resonance imaging investigation. It was revealed that this region lies at the inferior frontal eye field, where a pronounced activation over a larger region can be stimulated. Currently, more studies are needed to combine functional magnetic resonance imaging data of maximal activation with data from whole histologic brain sections of more individuals and to quantify the variability of this region and its sub-regions by means of a standardized brain atlas.
Aged↗
The cerebellum in the cerebro-cerebellar network for the control of eye and hand movements--an fMRI study.
The coordination of optical information and manipulation of objects in space by eye and hand movements is controlled by a cerebro-cerebellar network. The differential influence of prefrontal, motor, or parietal areas in combination with cerebellar areas, especially within the posterior hemispheres, on the control of eye and hand movements is not very well defined. Using fMRI we investigated the functional representation of isolated or combined eye and hand movements within the cerebellum and the impact of differential cognitive preload on the activation patterns. Each task consisted of the performance of saccades or hand movements triggered by a cue presented on a screen in front of the scanner. Saccades were tested for visually guided saccades, triple step saccades, and for visuospatial memory. Sequential finger opposition movements were tested for predictive and nonpredictive movements. Combined and isolated eye-hand reaching movements were tested toward a target presented in 5 different horizontal positions. Visually guided saccades activated the cerebellar vermis lobuli VI-VII, triple step saccades, including visuospatial memorization, in addition the cerebellar hemispheres lobuli VII-VIII. Sequential finger movements and reaching movements activated a cerebellar network consisting of the lobuli IV-VI, the vermis, and the lobuli VII-VIII with broader areas and additional regions especially within the lobus VII for more complex movements. The combined in contrast to the isolated performance of eye and hand movements demonstrated specialized activation foci within the cerebellar vermis and posterior hemispheres. We could demonstrate a differential representation of eye and hand movements within the cerebellum. Additional "cognitive" preload within a given task leads to additional activation of the posterior cerebellar hemispheres, with a subspecialization corresponding to premotor and parietal area connections.
Cerebellum↗
[Spatial neglect].
Unilateral spatial (hemi-)neglect or (hemi-)inattention are clinical terms used to describe a number of different clinical symptoms which have in common the patient's failure to attend to, respond adequately to, or orient voluntarily to people or objects in the contralesional space. Unilateral spatial neglect is most often observed following brain lesions affecting the right hemisphere, and in particular the right inferior parietal cortex (angular and supramarginal gyrus) and right temporoparietal junction. Importantly, the term hemineglect cannot be meaningfully used if the target behavior is explained by primary sensory or motor deficits only. Typically the patient's deficit is supramodal: patients with hemineglect fail to respond to novel or meaningful stimuli irrespective of whether they are presented in the visual, auditory, and somesthetic (somatosensory) domain. As adequate perception and spatial representation of both the body and the outside world are mandatory for almost all activities of daily living, hemineglect is known to limit the degree of active participation in rehabilitation programs and is thus commonly associated with poor functional recovery and less successful social reintegration. A number of new promising behavioral and pharmacological treatments may help to ameliorate neglect in the future.
Attention↗
Smooth pursuit deficits in schizophrenia, affective disorder and obsessive-compulsive disorder.
BACKGROUND: In schizophrenia, affective disorders, and obsessive-compulsive disorder (OCD) dysfunction of frontal neuronal circuits has been suggested. Such impairments imply corresponding oculomotor deficits. METHOD: Eye movement response to foveofugal and foveopetal step-ramp stimuli was recorded within the same study design in patients with schizophrenia (N= 16), affective disorder (N= 15), and OCD (N= 18) and compared with controls (N=23) using infra-red reflection oculography. RESULTS: In the foveofugal task steady-state velocity was lower in all patient groups compared with controls. Post-saccadic eye velocity was also decreased in patients with schizophrenia and affective disorder. In the foveopetal stimulus steady-state velocity was reduced in schizophrenic patients, only. Changes of saccadic latencies or position errors were not found in any of the patient groups. Also, pursuit latency was unchanged and initial eye acceleration was not decreased. CONCLUSIONS: Unaltered saccadic parameters indicate intact motion perception in cortical visual area V5. Therefore, the observed deficit of pursuit maintenance implies a dysfunction of frontal networks in all patient groups including the pursuit region of the frontal eye field (FEF). In patients with schizophrenia and affective disorder reduced post-saccadic pursuit initiation may indicate an impaired interaction between the pursuit and the saccadic system.
Adult↗
Horizontal canal benign paroxysmal positioning vertigo with ipsilateral hearing loss.
The etiology of benign paroxysmal positioning vertigo (h-BPPV) of the horizontal semicircular is unknown. Insight was obtained from two patients with h-BPPV and associated hearing impairment. Based on the different inner ear lesion patterns in neurolabyrinthitis contrary to ischemic labyrinthine infarction we assessed multiple vestibulo-cochlear functions for the first time in two patients who suffered from h-BPPV with sudden unilateral hearing loss. While in patient no. 1 the lesion pattern (posterior canal paresis in addition to the sudden hearing loss) could possibly be caused by ischemia of the common cochlear artery, the lesion pattern of patient no. 2 (hearing loss and ipsilateral paresis of the posterior and horizontal semicircular canal) exceeds the typical vascular labyrinthine territories and may indicate viral neurolabyrinthitis.
Adult↗
EFNS task force--therapy of nystagmus and oscillopsia.
An overview of possible treatment options for oculomotor disorders that prevent clear vision is given. Downbeat nystagmus, upbeat nystagmus, seesaw nystagmus, periodic alternating nystagmus, acquired pendular nystagmus, and saccadic oscillations such as opsoclonus/ocular flutter are discussed. In addition, superior oblique myokymia and vestibular paroxysmia are reviewed. All treatment recommendations available in the literature are classified as class C only. In general, only some of the patients benefit from the treatment.
Advisory Committees↗
Eye movement abnormalities in essential tremor may indicate cerebellar dysfunction.
Experimental and clinical data indicate that the cerebellum is involved in the pathophysiology of advanced stages of essential tremor (ET). The aim of this study was to determine whether a dysfunction also affects cerebellar structures involved in eye movement control. Eye movements of 14 patients with ET and 11 age-matched control subjects were recorded using the scleral search-coil technique. Vestibular function was assessed by electro-oculography. Eight ET patients had clinical evidence of intention tremor (ET(IT)); six had a predominantly postural tremor (ET(PT)) without intention tremor. ET patients showed two major deficits that may indicate cerebellar dysfunction: (i) an impaired smooth pursuit initiation; and (ii) pathological suppression of the vestibulo-ocular reflex (VOR) time constant by head tilts ('otolith dumping'). In the step ramp smooth pursuit paradigm, the initial eye acceleration in the first 60 ms of pursuit generation was significantly reduced in ET patients, particularly in ET(IT) patients, by approximately 44% (mean 23.4 degrees/s(2)) compared with that of control subjects (mean 41.3 degrees/s(2)). Subsequent steady-state pursuit velocity and sinusoidal pursuit gain (e.g. 0.4 Hz: 0.90 versus 0.78) were also significantly decreased in ET patients, whereas pursuit latency was unaffected. The intention tremor score correlated with the pursuit deficit, e.g. ET(IT) patients were significantly more affected than ET(PT) patients. Gain and time constant (tau) of horizontal VOR were normal, but suppression of the VOR time constant by head tilt ('otolith dumping') was pathological in 41% of ET patients, particularly in ET(IT) patients. Saccades and gaze-holding function were not impaired. The deficit of pursuit initiation, its correlation with the intensity of intention tremor, and the pathological VOR dumping provide additional evidence of a cerebellar dysfunction in the advanced stage of ET, when intention tremor becomes part of the clinical symptoms, and point to a common pathomechanism. The oculomotor deficits may indicate an impairment of the caudal vermis in ET.
Adult↗
Visual search in patients with left visual hemineglect.
In patients with hemi-spatial neglect eye movement patterns during visual search reflect not only inattention for the contralesional hemi-field, but interacting deficits of multiple visuo-spatial and cognitive functions, even in the ipsilesional hemi-field. Evidence for these deficits is presented from the literature and from saccadic scan-path analysis during feature and conjunction search in 10 healthy subjects and in 10 patients with manifest or recovered left visual neglect due to right-hemispheric stroke. Deficits include (1) a rightward shift of spatial representation, (2) deficient spatial working memory and failure of systematic search strategies, leading to multiple re-fixations, more after frontal lesions, and (3) a reduced spotlight of attention and a deficient pop-out effect of color, more after temporo-parietal lesions.
Adult↗
Perilymph fistula associated with pulse-synchronous eye oscillations.
Three-dimensional eye movements (scleral search coil system) were recorded in a patient with a surgically acquired perilymph fistula of the left horizontal semicircular canal. Spontaneous horizontal pendular nystagmus was found to be related to the heart rate and may be caused by pressure transfer of blood pulses to the labyrinth. In addition, a contralesional horizontal jerk nystagmus was elicited by Valsalva maneuver, indicating that Ewald's first law may not only be valid for excitation but also for inhibition.
Aged↗
Activation of frontoparietal cortices during memorized triple-step sequences of saccadic eye movements: an fMRI study.
To determine the cortical areas controlling memory-guided sequences of saccadic eye movements, we performed functional magnetic resonance imaging (fMRI) in six healthy adults. Subjects had to perform a memorized sequence of three saccades in darkness, after a triple-step stimulus of successively flashed laser targets. To assess the differential contribution of saccadic subfunctions, we applied several control conditions, such as central fixation with or without triple-step visual stimulation, self-paced saccades in darkness, visually guided saccades and single memory-guided saccades. Triple-step saccades strongly activated the regions of the frontal eye fields, the adjacent ventral premotor cortex, the supplementary eye fields, the anterior cingulate cortex and several posterior parietal foci in the superior parietal lobule, the precuneus, and the middle and posterior portion of the intraparietal sulcus, the probable location of the human parietal eye field. Comparison with the control conditions showed that the right intraparietal sulcus and parts of the frontal and supplementary eye fields are more involved in the execution of triple-step saccades than in the other saccade tasks. In accordance with evidence from clinical lesion studies, we propose that the supplementary eye field essentially controls the triggering of memorized saccadic sequences, whereas activation near the middle portion of the right intraparietal sulcus appears to reflect the necessary spatial computations, including the use of extraretinal information (efference copy) about a saccadic eye displacement for updating the spatial representation of the second or third target of the triple-step sequence.
Adult↗
Deficits of smooth pursuit initiation in patients with degenerative cerebellar lesions.
It is well known that cerebellar dysfunction can lead to an impairment of eye velocity during sustained pursuit tracking of continuously moving visual target. We have now studied the initiation of smooth pursuit eye movements towards predictable and randomized visual step-ramp stimuli in six patients with degenerative cerebellar lesions and six age-matched healthy controls using the magnetic scleral search-coil technique. In comparison with the control subjects, the cerebellar patients showed a significant delay of pursuit onset, and their initial eye acceleration was significantly decreased. These cerebellar deficits of pursuit initiation were similarly found in response to both randomized and predictable step-ramps, suggesting that predictive input does not compensate for cerebellar deficits in the initiation period of smooth pursuit. When we compared initial saccades during smooth tracking of foveofugal and foveopetal step-ramps, the absolute position error of these saccades did not significantly differ between patients and controls. In fact, none of the patients showed any bias of the saccadic position error that was related to the direction or velocity of the ongoing target motion. This work presents further evidence that the effect of cerebellar degeneration is not limited to the impaired velocity gain of steady-state smooth pursuit. Instead, it prolongs the processing time required to initiate smooth pursuit and impairs the initial eye acceleration. These two deficits were not associated with an abnormal assessment of target velocity and they were not modified by predictive control mechanisms, suggesting that cerebellar deficits of smooth initiation are not primarily caused by abnormal information on target motion being relayed to the cerebellum.
Adult↗
Electrooculography: technical standards and applications. The International Federation of Clinical Neurophysiology.
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Electromagnetic Phenomena↗
Exclusion of chromosome regions 6p12 and 15q11, but not chromosome region 7p11, in a German family with autosomal dominant congenital nystagmus.
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Chromosomes, Human, Pair 15↗
Distinguishing schizophrenic patients from healthy controls by quantitative measurement of eye movement parameters.
BACKGROUND: Eye tracking dysfunction is a putative trait marker for susceptibility to schizophrenia; however, it cannot be recommended as an additional tool for the diagnosis of schizophrenia, due to low sensitivity and specificity. METHODS: To assess the diagnostic potentials of combinations of eye movement paradigms, four smooth pursuit experiments (1: constant velocity of 15 degrees/sec; 2 and 3: combination with either visual or auditory distractors; 4: constant velocity of 30 degrees/sec) and two saccadic eye movement experiments (1: reflexive saccades; 2: voluntary saccades) were conducted. Fourteen patients with residual schizophrenia and 17 healthy controls were studied. Two sets of discriminant analyses (each with the resubstitution and with the "leaving one out" method) were calculated. RESULTS: In the first set, all 10 characteristic variables were included, whereas for the second set, the three most powerful parameters were selected (two from smooth pursuit tasks and one from a voluntary saccade experiment). This procedure provided the best classification results, regarding concordance between clinical diagnoses and eye movement dysfunction (kappa = .67-.80). CONCLUSIONS: Schizophrenic patients of the residual subtype can be differentiated from healthy individuals with considerable criterion validity on the basis of paradigms from two different ocular motor systems.
Adult↗
[Sensorimotor polyneuropathy and systemic amyloidosis as paraneoplastic symptoms of a carcinoid-like well differentiated carcinoma of the breast].
HISTORY AND ADMISSION FINDINGS: A 75-year-old woman was admitted because of weakness and paraesthesias in both legs. 15 years earlier a chest radiogram had shown numerous round foci of uncertain cause. Physical examination confirmed muscular weakness in all limbs, especially the legs, as well as abnormal superficial and deep sensory perception. INVESTIGATIONS: Electromyography registered a patchy pattern of intentional muscular activity and marked denervation activity but largely normal nerve conduction. There was no evidence of inflammatory disease in the laboratory tests, including the CNS. DIAGNOSIS, COURSE AND TREATMENT: The neurological findings indicated progressive axonal sensorimotor polyneuropathy. A paraneoplastic cause was suspected, but search for a primary tumour was unsuccessful. The patient developed a urinary infection from which she died in septic shock. A carcinoid-like well-differentiated carcinoma of the breast with hematogenous metastases to liver, spleen and lung was discovered at autopsy. It also revealed severe systemic AA-type amyloidosis, involving liver, spleen heart and kidneys. In addition there was a severe progressive axonal neuropathy and marked neurogenic atrophy of the peripheral skeletal musculature. No amyloid deposition was seen. CONCLUSION: In case of amyloidosis and polyneuropathy of uncertain cause a paraneoplastic pathogenesis should be considered in the differential diagnosis, even in the absence of proven malignancy.
Aged↗
Oculomotor testing in the differential diagnosis of degenerative ataxic disorders.
BACKGROUND: Oculomotor abnormalities have been reported in patients with degenerative ataxic disorders. OBJECTIVE: To assess the diagnostic sensitivity and specificity of oculomotor deficits in patients with Friedreich ataxia (FA), cerebellar atrophy (CA), and olivopontocerebellar atrophy (OPCA). SETTING: Neurology clinic at a university hospital in Lübeck, Germany. PATIENTS: Seven patients with FA, 9 with CA, and 10 with OPCA were studied. These patients were selected from an ongoing follow-up study. MAIN OUTCOME MEASURES: Eye movements were recorded by electro-oculography; an extensive battery of quantitative tests was used. RESULTS: A proven CAG repeat expansion on chromosome 6 or 14 was significantly associated with reduced saccadic eye velocity and vertical gaze palsy (P<.001, Mann-Whitney U test). All 6 patients with OPCA and slow saccades had an autosomal-dominant inheritance; 4 of them were proved to have spinocerebellar atrophy type 1. In 9 of these patients (4 with FA, 1 with CA, and 4 with OPCA), the genetic defect could not be identified. Saccadic dysmetria, impairment of smooth pursuit and optokinetic nystagmus, deficient suppression of the vestibulo-ocular reflex by either visual or otolith input, and pathological nystagmus were attributed to degenerative lesions in different parts of the cerebellum. However, these symptoms failed to clearly distinguish between the different groups of patients, whereas decreased vestibulo-ocular reflex gain, slow saccades, and vertical gaze palsy pointed to an extracerebellar manifestation of the degenerative disease, occurring only in patients with OPCA and FA. CONCLUSIONS: In this prospective study, oculomotor disturbances were mainly related to cerebellar dysfunction. Only a few of them were caused by extracerebellar manifestations of the disease, such as slowing of saccades, which was characteristic for patients with OPCA of autosomal-dominant inheritance.
Adult↗
Target anticipation and impairment of smooth pursuit eye movements in schizophrenia.
A reduced gain of smooth pursuit eye velocity has frequently been reported in schizophrenic patients. With respect to predictable stimuli, this could be due to a deficit in predicting the target path. To determine this contribution to smooth pursuit eye movement performance, we analyzed the ocular smooth pursuit response to a sinusoidally moving target that was suddenly stopped after some cycles of regular movement. Horizontal eye movements were recorded with infrared reflection oculography in a group of 17 schizophrenic in-patients and 16 age-matched healthy subjects for controls. The patients exhibited a reduced gain of smooth pursuit velocity, but phase lag was not different from the control group. After the unpredictable stop of target movement, predictive sinusoidal smooth pursuit was maintained for 150 to 200 ms in both groups. The resulting maximal position and velocity error was larger in the patient group. In conclusion, schizophrenic patients were able to generate a normal anticipatory component of smooth pursuit and to switch it off in response to external demands. They showed, however, an increased velocity of anticipatory pursuit, which might be used to compensate for the primary deficit of smooth pursuit velocity frequently found in schizophrenics.
Adaptation, Physiological↗