Lightning eye movements.

Physiologic studies were performed on a patient who demonstrated lightning eye movements, palatal myoclonus and myoclonic jerks of the left platysma and sternocleidomastoid muscles. The myoclonus and lightning eye movements were separate phenomena with no defined relationship to each other. Analysis of this ocular dyskinesia identified strictly horizontal saccadic oscillations, 2 to 5 Hz in frequency, with amplitudes varying greatly but often reaching 25 degrees. A brief stationary period between each saccadic oscillation was frequently observed. They were particularly induced by vertical or horizontal ocular pursuit as well as sustained upward or downward ocular deviation. Caloric nystagmus abolished the oscillations but they persisted, irregularly, during optokinetic nystagmus. Thus a faulty visual fixation mechanism is postulated to precipitate lightning eye movements. Constrast studies revealed a mass lesion arising from the right dorsolateral portion of the medulla. These results indicate that lightning eye movements occur with caudal as well as rostral brain-stem lesions. From the clinical findings cerebellar pathway involvement is likely.     

Ocular motor function in motor neuron disease.

We studied ocular motor function in 34 patients with motor neuron disease (MND) and in 18 age-matched controls. This included the latency, accuracy, and amplitude-velocity relationships of saccades. We also examined ocular pursuit, the slow phases of optokinetic nystagmus, and the ability to suppress the vestibulo-ocular reflex (VOR) with visual fixation of a head-mounted target. Five of the subjects with MND had pronounced parkinsonian features on neurologic examination. The nonparkinsonian MND subjects had normal ocular motor function for all measures. Most subjects suppressed the VOR completely. The parkinsonian-MND patients had impairment of both saccadic and pursuit eye movements, and one parkinsonian-MND patient with poor pursuit was unable to suppress the VOR. We conclude that ocular motor function is generally spared in MND. The occasional appearance of ocular motor dysfunction probably reflects the incidence of secondary abnormalities such as parkinsonism.     

A Variation in FGF14 Is Associated with Downbeat Nystagmus in a Genome-Wide Association Study

The Cerebellum - Downbeat nystagmus (DBN) is a frequent form of acquired persisting central fixation nystagmus, often associated with other cerebellar ocular signs, such as saccadic smooth pursuit...     

Ataxia telangiectasia: a reappraisal of the ocular motor features and their value in the diagnosis of atypical cases

The eye movements of four patients with ataxia telangiectasia (AT), three of whom had an unusual neurological presentation, were studied. All had striking abnormalities of saccadic generation with markedly hypometric saccades, increased saccadic latency, but normal saccadic velocity. Three patients used head thrusts to aid refixation. In addition, there was absence of smooth pursuit and optokinetic nystagmus, and hyperactive vestibular responses. Two of the four patients had, in addition, periodic alternating nystagmus. This combination of an ocular motor apraxia with superadded cerebellar ocular motor abnormalities, and possibly periodic alternating nystagmus, should strongly suggest the diagnosis of AT, even if the clinical syndrome is otherwise atypical.     

Supranuclear disturbances of ocular motility in Lytico-Bodig

We found abnormal supranuclear ocular or lid motility in all of 37 patients with Lytico-Bodig (amyotrophic lateral sclerosis/parkinsonism-dementia complex). Twenty-one patients had pursuit paresis, 18 abnormal vestibulo-ocular reflex (VOR) cancellation, 15 abnormal convergence, 13 abnormal optokinetic nystagmus (OKN), 12 conjugate gaze limitation, nine nystagmus, nine saccadic paresis, and six abnormal fixation. Lid abnormalities included glabellar hyperreflexia in 21, involuntary levator inhibition in three, and blepharospasm in two. Earlier reports have indicated infrequent ocular disturbances in Lytico-Bodig, but we now find supranuclear eye and lid deficits are universal and sometimes very prominent.     

Failure of fixation suppression of caloric nystagmus and ocular motor abnormalities

Caloric nystagmus is substantially suppressed by visual fixation. The degree of suppression of caloric nystagmus is influenced by the condition of visual fixation. We studied the percent reduction in slow-phase velocity of caloric nystagmus by visual fixation and certain abnormalities in optokinetic nystagmus, smooth pursuit, and maintenance of ocular position of gaze in 38 patients with disorders of the CNS. The inability to suppress caloric nystagmus by visual fixation correlated with reduction in optokinetic nystagmus, deficit in smooth pursuit eye movements, and presence of gaze nystagmus. It seems probable that modulation of the vestibulo-ocular reflex is influenced by the same mechanisms that are concerned with optokinetic nystagmus, maintenance of ocular position of gaze, and smooth pursuit eye movements.     

Familial vestibulocerebellar dysfunction: a new syndrome?

Three members of a single family with the symptom of "motion sickness" showed rebound nystagmus, saccadic pursuit eye movements, defective optokinetic slow phase velocity and lack of fixation suppression of vestibularly induced nystagmus. One of them showed vestibular hyperreactivity and a gradual build-up of the optokinetic response. In absence of other abnormalities, these findings can be localized to the vestibulocerebellum (flocculo-nodular lobe).     

Multiple system atrophy with macro square wave jerks and pendular nystagmus]

A 51-year-old woman was admitted to our hospital because of gait disturbance and dysuria. Neurological examination revealed limb and truncal ataxia, orthostatic hypotension, cogwheel rigidity in all limbs, generalized hyperreflexia without pathological reflex, and horizontal gaze nystagmus. She became progressively worse and bedridden at age 52. Then she developed abnormal eye movements. Electrooculogram revealed vertical, horizontal or oblique macro square wave jerks and pendular nystagmus. Macro square wave jerks appeared during fixation and disappeared with eye closure or in the dark room. Macro square wave jerks were characterized by a duration of about 200 msec and an amplitude of 10 to 15 degrees. Pendular nystagmus with a duration of several seconds and amplitude of 5 to 15 degrees appeared when she changed her fixation or the point of fixation disappeared. Macro square wave jerks and pendular nystagmus were mildly suppressed after the intramuscular injection of 100 mg of phenobarbital, the oral intake of sodium valproate of 600 mg/day or baclofen of 60 mg/day. They were almost completely depressed after the intravenous injection of 3 mg of diazepam or the oral intake of clonazepam of 1.5 mg/day. We suggested that both macro square wave jerks and pendular nystagmus in this patient might be caused by the dysfunction of GABAergic system in the saccadic eye movement system.     

Increased saccadic distractibility in tardive dyskinesia: functional evidence for subcortical GABA dysfunction

In mammals, GABAergic projections from the substantia nigra reticulata to the superior colliculus provide tonic inhibition to tectal neurons involved in the generation of saccades. Dysfunction of this pathway has been shown to produce saccadic "distractibility" in the experimental monkey. In two oculomotor paradigms, control of saccadic eye movements was tested in chronic schizophrenic patients with (n = 18) and without (n = 16) tardive dyskinesia (TD) and normal controls (n = 8). The three groups were matched by mean age; the TD and non-TD patient groups had similar duration of illness, benztropine and chlorpromazine equivalent doses and educational levels. A twofold increase in saccadic distractibility was observed in TD compared to non-TD schizophrenic patients, and both patient groups demonstrated a greater saccadic distractibility than normals. Furthermore, schizophrenic patients (both with and without TD) showed significantly increased latency for "volitional" saccades compared to the normal controls. These findings may provide further evidence for basal ganglia GABA dysfunction in tardive dyskinesia, as well as demonstrate oculomotor abnormalities in schizophrenic individuals.     

Oculomotor abnormalities in Friedreich's ataxia.

A clinical neuro-ophthalmological and electro-oculographic study was made on fourteen patients with Friedreich's ataxia. None had evidence of optic nerve dysfunction. No patient complained of oscillopsia although all had ocular motor deficits of varying degrees, which appeared to be related to the severity of the general manifestations of the disease. The defects comprised square wave jerks, jerky pursuit with inability to maintain eccentric gaze resulting in gaze paretic nystagmus and rebound nystagmus. There was failure to suppress by fixation the vestibulo-ocular reflex. The slow phase velocity of caloric nystagmus was always of reduced velocity. There was inability to augment the slow phase velocity of optokinetic nystagmus with increasing stimulus velocity. Abnormalities of the saccadic system were manifest particularly as hypermetria. These signs in combination are suggestive of disease involving the cerebellar flocculus and vermis or their brain stem connections. No abnormalities were found in 17 parents or siblings.     

Oculomotor and vestibular findings in autosomal recessive spastic ataxia of Charlevoix-Saguenay.

Electronystagmographic recordings were made of oculomotor and vestibular function in 11 patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay. All had horizontal gaze nystagmus, marked impairment of smooth ocular pursuit and optokinetic nystagmus, and defective fixation suppression of caloric nystagmus. Many had saccadic dysmetria, but saccade velocity was probably unaffected. Abnormalities pointing to brainstem disturbance were sparse. The findings are thought to indicate mainly diffuse cerebellar disease, with particular involvement of vermis and vestibulo-cerebellum.     

Ocular motor abnormalities in progressive supranuclear palsy

Eleven patients, 7 males and 4 females, of progressive supranuclear palsy (PSP) were examined neuro-otologically for the purpose of elucidating the characteristics of ocular motor abnormalities. All cases were admitted to our hospital and age at onset was from 52 to 71 years old, duration of illness was 2 to 11 years. Range of voluntary eye movements and abnormal eye movements including nystagmus were examined on naked eyes and with electronystagmography (ENG). Smooth pursuit movements and saccadic eye movements were tested both horizontally and vertically by using visual tracking method with ENG recordings. Optokinetic nystagmus test and caloric test with visual suppression test were also performed. These neurotological examinations were made repetitively in 5 cases and their progressions were observed. Vertical gaze palsy and convergence palsy were observed in all cases as the initial symptom. In this study downward gaze was more severely disturbed than upward gaze. Using ENG, saccadic eye movements (saccades) were disturbed earlier than smooth pursuit movements. Hypometric saccades and decreased saccadic velocity were common abnormalities. In the later stage of the disease, horizontal eye movements were also disturbed. In four cases bilateral adduction palsy was added to vertical gaze paralysis so that the lesion of the MLF to oculomotor nucleus was suggested to exist. These voluntary eye movements were worsened gradually as the disease progressed. By using ENG we could find so called abnormal eye movements more frequently than the previous reports. Eight patients demonstrated horizontal gaze nystagmus, and rebound nystagmus were observed in four cases.(ABSTRACT TRUNCATED AT 250 WORDS)     

A rare saccade velocity profile in Stiff-Person Syndrome with cerebellar degeneration

Stiff-Person Syndrome (SPS) is an immune-mediated disorder of the central nervous system characterized by muscle rigidity, episodic muscle spasms, and high titers of antibodies against glutamic acid decarboxylase (GAD). The presence of cerebellar ataxia in SPS is extremely rare, but occurs. Clinical observations of ocular motor abnormalities have been noted in a few SPS patients. The purpose of this study is to provide a detailed quantitative documentation of ocular motor abnormalities in a patient with SPS and progressive cerebellar signs. Detailed clinical assessment of a woman with SPS and precise eye movement recordings using the magnetic search coil technique was performed. In addition to other ocular motor abnormalities that included longer latencies for saccades, downbeat nystagmus, and loss of downward smooth pursuit, a rare saccade velocity profile consisting of multi-component saccades was observed. We postulate that these ocular motor findings are related to impairment of GABAergic neurotransmission because antibodies to glutamic acid decarboxylase (GAD-Abs) have been implicated in the pathogenesis of both SPS and some cases of cerebellar ataxia. In addition, this unusual saccadic velocity profile may have important implications for modeling the saccadic system and furthering a complete understanding of saccade generation.     

A hypothetical explanation of saccadic oscillations.

Eye movements in a patient with saccadic oscillations (ocular flutter) were recorded and analyzed. Findings were related to recent microelectrode studies in the monkey pontine reticular formation which have identified three types of premotor neurons related to saccadic eye movements: burst, tonic, and pause cells. We incorporated these cell types into a hypothetical circuit that generates saccades by rapidly driving the eye to a designated orbital position rather than preprogramming a distance for movement. Physiological measurements suggest that this neural network is unstable and that the burst neurons must be tonically inhibited to prevent saccadic oscillations during periods of fixation. Pause cells, which discharge tonically except during saccades, when they pause, appear to inhibit burst cells and prevent such saccadic oscillations. Analysis of our patient's behavior indicates that many types of saccadic oscillations can be explained and classified by assuming an abnormality of pause cell control over saccadic burst neurons.     

Vertical and horizontal epileptic gaze deviation and nystagmus

Periods of epileptic nystagmus consisting of rightward eye deviation and right-beating nystagmus, alternating with upward eye deviation and upbeating nystagmus, occurred in a comatose patient with a left hemisphere subdural hematoma and seizures. The periods of upbeating nystagmus were associated with symmetric, low-voltage 3 to 4 Hz bifrontal spikes. Rightward eye deviation and right-beating nystagmus occurred with diffuse, predominantly left hemispheric 4 to 6 Hz sharp waves. No eye movements occurred in the absence of spike and wave activity. These correlations agree with current concepts of the cortical control of saccadic eye movements in monkeys studied by electrical stimulation.     

Multi-system signs and symptoms in X-linked ataxia carriers

Neurological, auditory, vestibular and ocular motor examinations were performed on 3 definite and 3 possible heterozygous carriers of a previously described X-linked multi-system disorder with early childhood onset, rapid progression and a fatal outcome (Arts et al., 1993). The symptoms i.e., delayed motor development, ataxia, hearing loss and subnormal intelligence, were so evident in 2 of the possible carriers that they could be redesignated as probable carriers. Other symptoms in the definite and probable carriers were clubfeet, dysarthria, intention tremor and abnormal gait, while their signs included dysdiadochokinesia, ataxic paraplegia, abnormal muscle tendon reflexes and extensor plantar responses. All the symptomatic carriers developed moderate-to-severe sensorineural hearing loss with normal stapedial reflexes and brain stem auditory evoked potentials (BAEPs) in those in whom this could be evaluated. Speech discrimination was disproportionally poor unilaterally in one case from whom no BAEPs could be obtained because of her degree of hearing loss. Various combinations were found of high gain of the vestibulo-ocular reflex, spontaneous nystagmus and directional preponderance of vestibularly evoked nystagmus, slowing, hypometria or multi-stepping of saccades, saccadic intrusions of eye movements (macro square wave jerks, double saccadic pulses), impairment of smooth pursuit eye movements and optokinetic nystagmus, and failure of visual fixation suppression of vestibularly evoked nystagmus. Such findings indicate major involvement of the (vestibulo)cerebellum and the vermis. MRI in one carrier showed mild cerebellar atrophy.     

Convergence-initiated voluntary flutter: A normal intrinsic capability in man

The proposal that there is an inherent capability in humans to produce bursts of fluttering saccades was tested by comparing Purkinje image eye movement recordings in subjects with voluntary nystagmus and control subjects. Voluntary nystagmus is composed of recurrent saccades without an intersaccade interval and has been proposed to be an inherited event. No difference in saccade peak velocity-amplitude curves or microsaccades during visual fixation was found between the two groups. With training control subjects learned to produce runs of saccadic flutter identical to voluntary nystagmus. This learned flutter was composed of recurrent complete saccades rather than saccades interrupted in midflight. Voluntary flutter is thus not a genetic trait but a learned event that is usually undeveloped in man. These observations can be explained by the Robinson model of saccade generation and indicate that similar models must have an inherent ability to produce saccadic flutter.     

Primary position upbeat nystagmus. A clinicopathologic study

Eye movements were studied with electro-oculography in a patient with primary position, large amplitude, upbeat nystagmus. The upbeat nystagmus increased in amplitude on upward gaze, decreased on downward gaze, and was not altered by loss of fixation. The patient could not produce smooth pursuit movements upward or to the left, but had normal saccadic and vestibular induced eye movements in all directions. At necropsy, a low grade glioma was found involving primarily the medulla and caudal pons. The inferior olives and prepositus hypoglossal nuclei were diffusely infiltrated with tumor. These results suggest (1) primary position upbeat nystagmus is due to a defect in the upward smooth pursuit system, (2) the lower brain stem at the level of the inferior olives and nucleus prepositus hypoglossi is important in the mediation of vertical pursuit, and (3) primary position upbeat nystagmus can result from damage to several nuclei and interconnecting pathways in the caudal brain stem and midline cerebellum involved in control of vertical smooth pursuit.     

Ocular oscillations induced by shifts of the direction and depth of visual fixation

Shifts of the point of fixation between two targets aligned on one eye that are located near and far (Müller paradigm) stimulates a combined saccadic-vergence movement. In normal subjects, this test paradigm often induces saccadic oscillations of about 0.3 degrees at 20 to 30 Hz. We measured eye movements using the magnetic search coil technique in 2 patients recovering from viral opsoclonus-myoclonus syndrome, comparing saccadic-vergence responses to the Müller paradigm with conjugate saccades between distant targets. Both patients exhibited intermittent conjugate ocular oscillations of about 4 to 5 degrees amplitude at about 10 Hz. Combined saccadic-vergence movements induced these oscillations twice as often as did conjugate saccades. One patient also exhibited disjunctive ocular oscillations at 10 Hz while sustaining fixation on the near target. The Müller paradigm provides a useful clinical and experimental technique for inducing saccadic oscillations. The probable mechanism is that pontine omnipause neurons, which normally gate saccades, are inhibited during the sustained vergence movement that follows the saccadic component of the response to the Müller paradigm.     

Ocular motor characteristics of different subtypes of spinocerebellar ataxia: Distinguishing features

Because of frequent involvement of the cerebellum and brainstem, ocular motor abnormalities are key features of spinocerebellar ataxias and may aid in differential diagnosis. Our objective for this study was to distinguish the subtypes by ophthalmologic features after head‐shaking and positional maneuvers, which are not yet recognized as differential diagnostic tools in most common forms of spinocerebellar ataxias. Of the 302 patients with a diagnosis of cerebellar ataxia in 3 Korean University Hospitals from June 2011 to June 2012, 48 patients with spinocerebellar ataxia types 1, 2, 3, 6, 7, or 8 or with undetermined spinocerebellar ataxias were enrolled. All patients underwent a video‐oculographic recording of fixation abnormalities, gaze‐evoked nystagmus, positional and head‐shaking nystagmus, and dysmetric saccades. Logistic regression analysis controlling for disease duration revealed that spontaneous and positional downbeat nystagmus and perverted head‐shaking nystagmus were strong predictors for spinocerebellar ataxia 6, whereas saccadic intrusions and oscillations were identified as positive indicators of spinocerebellar ataxia 3. In contrast, the presence of gaze‐evoked nystagmus and dysmetric saccades was a negative predictor of spinocerebellar ataxia 2. Positional maneuvers and horizontal head shaking occasionally induced or augmented saccadic intrusions/oscillations in patients with spinocerebellar ataxia types 1, 2, and 3 and undetermined spinocerebellar ataxia. The results indicated that perverted head‐shaking nystagmus may be the most sensitive parameter for SCA6, whereas saccadic intrusions/oscillations are the most sensitive for spinocerebellar ataxia 3. In contrast, a paucity of gaze‐evoked nystagmus and dysmetric saccades is more indicative of spinocerebellar ataxia 2. Head‐shaking and positional maneuvers aid in defining ocular motor characteristics in spinocerebellar ataxias. © 2013 Movement Disorder Society