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Objective: This study assessed the feasibility of administering a multidimensional, self-report pain assessment protocol to children in an inpatient, acute pain context, and sought insight into the interrelationships between sensory, affective, and evaluative pain dimensions., Methods: A total of 132 children (5 to 16 y) experiencing acute pain were recruited from acute pain ward rounds or the short-stay surgical unit. A multidimensional self-report assessment protocol was administered, assessing pain intensity, pain-related affect, bother, perceived unfairness, and pain expectations (for tomorrow and in 1 wk). Duration of protocol administration was assessed and ease of administration was rated. Pain-related behaviors were rated using the Face, Legs, Activity, Cry, and Consolability (FLACC) Scale., Results: The duration of protocol administration was <2.5 minutes, on average, for all age groups. Median ease of protocol administration was 7/10 for 5- to 7-year-olds and 8/10 for older age groups. Pain-related bother was higher for 14- to 16-year-olds, relative to younger age groups, and significantly correlated with perceived unfairness (r=0.59, P<0.01), intensity (r=0.76, P<0.01), and affect (r=0.33, P<0.05). For younger age groups, bother was significantly positively correlated only with pain intensity (rs=0.59 to 0.79, Ps<0.01) and affect (rs=0.4 to 0.71, Ps <0.05). A stepwise multiple regression analysis found multidimensional self-reported information (especially pain intensity and perceived unfairness), accounted for significant additional amount of variance, beyond that explained by age, pain duration, and observed pain behavior., Discussion: Sensory, affective, and evaluative aspects of children's clinical, acute pain experience may be assessed using self-report tools, which provide unique and valuable information about their pain experience., Competing Interests: T.J. position is supported by the Sydney Children’s Hospital Foundation, Randwick, NSW, Australia. The remaining authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Although pain is widely recognized to be a multidimensional experience and defined as such, unidimensional pain measurement focusing on pain intensity prevails in the pediatric acute pain context. Unidimensional assessments fail to provide a comprehensive picture of a child's pain experience and commonly do little to shape clinical interventions. The current review paper overviews the theoretical and empirical literature supporting the multidimensional nature of pediatric acute pain. Literature reporting concordance data for children's self-reported sensory, affective and evaluative pain scores in the acute pain context has been reviewed and supports the distinct nature of these dimensions. Multidimensional acute pain measurement holds particular promise for identifying predictive markers of chronicity and may provide the basis for tailoring clinical management. The current paper has described key reasons contributing to the widespread use of unidimensional, rather than multidimensional, acute pediatric pain assessment protocols. Implications for clinical practice, education and future research are considered.

Purpose: Abnormalities in saccades appear to be sensitive and specific biomarkers in the prediagnostic stages of Huntington disease (HD). The goal of this study was to evaluate test-retest reliability of saccadic measures in prediagnostic carriers of the HD gene expansion (PDHD) and normal controls (NC)., Methods: The study sample included 9 PDHD and 12 NC who completed two study visits within an approximate 1-month interval. At the first visit, all participants completed a uniform clinical evaluation. A high-resolution, video-based system was used to record eye movements during completion of a battery of visually guided, antisaccade, and memory-guided tasks. Latency, velocity, gain, and percentage of errors were quantified. Test-retest reliability was estimated by calculating the intraclass correlation (ICC) of the saccade measures collected at the first and second visits. In addition, an equality test based on Fisher's z-transformation was used to evaluate the effects of group (PDHD and NC) and the subject's sex on ICC., Results: The percentage of errors showed moderate to high reliability in the antisaccade and memory-guided tasks (ICC = 0.64-0.93). The latency of the saccades also demonstrated moderate to high reliability (ICC = 0.55-0.87) across all tasks. The velocity and gain of the saccades showed moderate reliability. The ICC was similar in the PDHD and NC groups. There was no significant effect of sex on the ICC., Conclusions: Good reliability of saccadic latency and percentage of errors in both antisaccade and memory-guided tasks suggests that these measures could serve as biomarkers to evaluate progression in HD.

Objective: To evaluate quantitative measures of saccades as possible biomarkers in early stages of Parkinson disease (PD) and in a population at-risk for PD., Methods: The study sample (n=68) included mildly to moderately affected PD patients, their unaffected siblings, and control individuals. All participants completed a clinical evaluation by a movement disorder neurologist. Genotyping of the G2019S mutation in the LRRK2 gene was performed in the PD patients and their unaffected siblings. A high resolution, video-based eye tracking system was employed to record eye positions during a battery of visually guided, anti-saccadic (AS), and two memory-guided (MG) tasks. Saccade measures (latency, velocity, gain, error rate, and multiple step pattern) were quantified., Results: PD patients and a subgroup of their unaffected siblings had an abnormally high incidence of multiple step patterns (MSP) and reduced gain of saccades as compared with controls. The abnormalities were most pronounced in the more challenging version of the MG task. For this task, the MSP measure demonstrated good sensitivity (87%) and excellent specificity (96%) in the ability to discriminate PD patients from controls. PD patients and their siblings also made more errors in the AS task., Conclusions: Abnormalities in eye movement measures appear to be sensitive and specific measures in PD patients as well as a subset of those at-risk for PD. The inclusion of quantitative laboratory testing of saccadic movements may increase the sensitivity of the neurological examination to identify individuals who are at greater risk for PD.

The objective of this study was to evaluate visual scanning strategies in carriers of the Huntington disease (HD) gene expansion and to test whether there is an association between measures of visual scanning and cognitive performance. The study sample included control (NC, n = 23), prediagnostic (PDHD, n = 21), and subjects recently diagnosed with HD (HD, n = 19). All participants completed a uniform clinical evaluation that included examination by neurologist and molecular testing. Eye movements were recorded during completion of the Digit Symbol Subscale (DS) test. Quantitative measures of the subject's visual scanning were evaluated using joint analysis of eye movements and performance on the DS test. All participants employed a simple visual scanning strategy when completing the DS test. There was a significant group effect and a linear trend of decreasing frequency and regularity of visual scanning from NC to PDHD to HD. The performance of all groups improved slightly and in a parallel fashion across the duration of the DS test. There was a strong correlation between visual scanning measures and the DS cognitive scores. While all individuals employed a similar visual scanning strategy, the visual scanning measures grew progressively worse from NC to PDHD to HD. The deficits in visual scanning accounted, at least in part, for the decrease in the DS score.

Eye-head gaze pursuit-related activity was recorded in rostral portions of the nucleus reticularis tegmenti pontis (rNRTP) in alert macaques. The head was unrestrained in the horizontal plane, and macaques were trained to pursue a moving target either with their head, with the eyes stationary in the orbits, or with their eyes, with their head voluntarily held stationary in space. Head-pursuit-related modulations in rNRTP activity were observed with some cells exhibiting increases in firing rate with increases in head-pursuit frequency. For many units, this head-pursuit response appeared to saturate at higher frequencies (>0.6 Hz). The response phase re:peak head-pursuit velocity formed a continuum, containing cells that could encode head-pursuit velocity and those encoding head-pursuit acceleration. The latter cells did not exhibit head position-related activity. Sensitivities were calculated with respect to peak head-pursuit velocity and averaged 1.8 spikes/s/deg/s. Of the cells that were tested for both head- and eye-pursuit-related activity, 86% exhibited responses to both head- and eye-pursuit and therefore carried a putative gaze-pursuit signal. For these gaze-pursuit units, the ratio of head to eye response sensitivities averaged approximately 1.4. Pursuit eccentricity seemed to affect head-pursuit response amplitude even in the absence of a head position response per se. The results indicated that rNRTP is a strong candidate for the source of an active head-pursuit signal that projects to the cerebellum, specifically to the target-velocity and gaze-velocity Purkinje cells that have been observed in vermal lobules VI and VII.

Purpose: To describe an unusual form of acquired ocular motor apraxia., Methods: Case reports with electronic eye movement recordings., Results: Three patients had surgery to repair aortic root or arch dissections or aneurysms. A few days after surgery, all had ophthalmoplegia. Neuro-ophthalmic examination found complete absence of horizontal and vertical volitional and reflex saccades in 1 patient and slow, hypometric saccades in 2 others. However, smooth pursuit, slow phases of optokinetic nystagmus, and the vestibulo-ocular response (VOR) were intact. Fast phases of the VOR were absent in 2 patients but were intact in the other. Video and electronic eye movement recordings documented the findings. Magnetic resonance imaging (MRI) in 1 patient showed small infarcts in a cerebellar hemisphere, pons, and cerebral hemispheres. The other patients' MRIs showed no significant lesions., Conclusions: Acquired ocular motor apraxia with profoundly impaired volitional saccades after aortic surgery is a distinctive syndrome, but its pathophysiology is unclear. Studies of neurologic damage in animals and patients undergoing similar surgical procedures provide conflicting data. However, knowledge about the complex neural pathways generating saccades from animal and human studies, and detailed clinical observations, as in the patients described here, can help to determine the location of lesions. Based on the 3 cases reported here, we propose that this syndrome might be due to damage to excitatory burst and/or omnipause neurons in the brainstem or by damage to pathways from the frontal eye fields to the brainstem.

We compared oculomotor control among individuals in the early stages of Huntington's disease (HD), with that of individuals who are presymptomatic HD gene carriers (PSGC) and nongene carriers (NGC). The oculomotor testing paradigm included both traditional tests and a novel experimental procedure to assess visual scanning. Traditional tests elicited saccades, pursuit and optokinetic nystagmus (OKN). HD patients demonstrated marked delay in the initiation of volitional saccades (anti-saccade and memory-guided saccades), a reduced number of correct volitional saccades, reduced velocity of saccades, and a decreased OKN gain. We also studied visual scanning while the participants completed the Digit Symbol Subscale of the Wechsler Adult Intelligence Survey-Revised (WAIS-R). The HD participants demonstrated an abnormal gaze strategy, which may be associated with attention and/or planning deficits. Differences between the PSGC and NGC groups were only observed for two measures: PSGC had a decreased number of memory-guided saccades and a subtle delay in the initiation of volitional saccades. Our results suggest that oculomotor measures are a sensitive biomarker in the early stage of HD and demonstrate that the combination of more traditional oculomotor tests with visual scanning tests is useful in the evaluation of visual performance.

Surgery on the eye is performed using topical anesthesia, retrobulbar anesthesia, peribulbar anesthesia, and general anesthesia. Retrobulbar anesthesia is associated with a number of complications that include apnea (respiratory arrest), seizures, or both. Although these complications are transient and self-limiting, they can be life-threatening if not recognized and treated early. We report two patients who developed apnea, one of whom had cardiorespiratory arrest; and two other patients who presented with seizures. We provided ventilation with 100% oxygen, treated the hypertension with nicardipine, and the tachycardia with esmolol. The patients did not have any residual complications.

Neuronal responses that were observed during smooth-pursuit eye movements were recorded from cells in rostral portions of the nucleus reticularis tegmenti pontis (rNRTP). The responses were categorized as smooth-pursuit eye velocity (78%) or eye acceleration (22%). A separate population of rNRTP cells encoded static eye position. The sensitivity to pursuit eye velocity averaged 0.81 spikes/s per degrees /s, whereas the average sensitivity to pursuit eye acceleration was 0.20 spikes/s per degrees /s(2). Of the eye-velocity cells with horizontal preferences for pursuit responses, 56% were optimally responsive to contraversive smooth-pursuit eye movements and 44% preferred ipsiversive pursuit. For cells with vertical pursuit preferences, 61% preferred upward pursuit and 39% preferred downward pursuit. The direction selectivity was broad with 50% of the maximal response amplitude observed for directions of smooth pursuit up to +/-85 degrees away from the optimal direction. The activities of some rNRTP cells were linearly related to eye position with an average sensitivity of 2.1 spikes/s per deg. In some cells, the magnitude of the response during smooth-pursuit eye movements was affected by the position of the eyes even though these cells did not encode eye position. On average, pursuit centered to one side of screen center elicited a response that was 73% of the response amplitude obtained with tracking centered at screen center. For pursuit centered on the opposite side, the average response was 127% of the response obtained at screen center. The results provide a neuronal rationale for the slow, pursuit-like eye movements evoked with rNRTP microstimulation and for the deficits in smooth-pursuit eye movements observed with ibotenic acid injection into rNRTP. More globally, the results support the notion of a frontal and supplementary eye field-rNRTP-cerebellum pathway involved with controlling smooth-pursuit eye movements.

Objective: To evaluate the influence of family history of alcoholism (FHA) on the response of saccadic eye movements to alcohol., Method: Saccadic performance was evaluated in 54 healthy adult subjects with a FHA (family history-positive) and 49 controls (family history-negative). Alcohol and placebo sessions were presented in counterbalanced order. Alcohol was administered intravenously to achieve and maintain a target breath alcohol concentration of 60 mg/100 ml (60%) for 160 min in each subject. During each session, saccadic eye movement testing was performed at baseline (before infusion of alcohol) and twice during the steady-state target breath alcohol concentration. The saccadic testing elicited visually guided saccades (VGS) and antisaccades (AS). Saccadic latency and velocity and the percentage of AS errors were quantified and analyzed using multivariate analysis of variance., Results: The family history-positive and family history-negative groups showed an overall difference at baseline in AS and VGS latencies and velocities in the alcohol and placebo sessions ( p= 0.006). Alcohol delayed saccades such that AS and VGS latencies increased (p = 0.0001) and slowed the execution of saccades such that peak velocities decreased ( p = 0.0002). The percentage of AS errors decreased after alcohol administration, but no significant effect of alcohol (alcohol versus placebo session) was observed (p = 0.1). Latency of AS saccades demonstrated a significant overall FHA effect (p = 0.02) and a significant interaction between FHA and response to alcohol over time (p = 0.02)., Conclusions: Differences in operational characteristics of the saccadic control system are associated with FHA in adult social drinkers, both at baseline and when the brain is exposed to ethanol at 60 mg/100 ml.

Background: The primary goal of this study was to evaluate how race and sex interact with the effects of a moderate dose of alcohol on different ocular control subsystems in African American (AA) and non-Hispanic white American (WA) college students., Methods: Horizontal visually guided (VG) saccades and antisaccades (AS) of 80 young adult, healthy, AA and WA college students were recorded with an infrared system. Subjects ingested 10 aliquots of ethanol at 3 min intervals, with the aggregate dose precalculated to yield a peak breath alcohol concentration (BrAC) of 80 mg%. Data from the measures performed at baseline and the ascending and descending limbs of the BrAC at approximately 65 mg% were compared across race and sex by multivariate analysis of variance. A no-alcohol control session, performed in 20 of the subjects, documented test-retest reliability of the VG and AS measurements., Results: Both AA and WA groups demonstrated slowing of AS and VG saccades after alcohol administration, but there was no significant effect of 65 mg% alcohol on VG accuracy or AS errors. AS latency recovered toward baseline values, whereas the slowing of VG latency/velocity progressed, during alcohol exposure. There were significant differences between AA and WA groups in the time course of VG latency after alcohol but not in most other dependent measures. No significant effects for sex were observed in any of the saccade measures. The faster disappearance of alcohol in WA compared with AA was replicated, and some measures demonstrated a significant, albeit small, negative correlation between the alcohol disappearance rate and impairing effects of alcohol on saccades., Conclusions: Prolonged latencies and unchanged percentage of errors reflect a differential effect of alcohol on neural function in specific areas (parietal eye field, superior colliculus, and frontal eye areas). Race may interact with the effect of ethanol on saccadic eye movements in a college student population.

Objectives: Studies of saccadic eye movement impairment in Alzheimer's disease (AD) have largely focused on simple reflexive eye movements and the antisaccade task. The effects of manipulating stimulus timing have been little studied., Methods: Fourteen patients with mild to severe AD and 11 age-matched controls were studied on the antisaccade task, while latencies on simultaneous, gap and predictable tasks were recorded from 11 patients and 11 controls. Dementia severity was assessed with the Mini-Mental State Examination., Results: As a group, patients' latencies were significantly higher and more variable on the simultaneous and gap tasks. Predictable task performance was similar in mean but significantly more variable. Grossly anticipatory responses by patients were common on the predictable, simultaneous and gap tasks. Exclusion of these from subject means revealed that AD patients, when making target-driven saccades, demonstrated a gap effect of similar magnitude to normal subjects. Patients made significantly fewer correct antisaccades and significantly more reflexive errors not followed by a corrective antisaccade than did controls., Conclusions: The frequent presence of grossly anticipatory saccades may reflect dysfunction of fixation mechanisms possibly involving projections from frontal lobe to superior colliculus. The less frequently seen, marked prolongation of latency may reflect changes in posterior parietal mechanisms mediating reflexive saccade generation. The presence of the gap effect demonstrates a continued ability to benefit from externally controlled stimulus disengagement. Patients' ability to make appropriately timed saccades to targets of known locations was particularly impaired, but the target sequence itself was at least grossly correctly learned. Larger studies may be able to identify clinically distinct populations of AD patients., (Copyright 2002 S. Karger AG, Basel)

Peter Hispanus, who became Pope John XXI, wrote a book about eye diseases and their treatment in the 13th century. De Oculis was not a scholarly treatise about eye diseases, but a manual intended for general physicians. Nevertheless, Latin copies were made into the 16th century, indicating its influence and importance. We present the first published English translation of De Oculis, based on a synthesis of the medieval Latin manuscripts and a German translation from the 19th century. The sources of Peter's understanding of the causes and treatment of eye diseases were the more scholarly and complete treatises by Greek and Arab writers. Many of the diseases described then cannot be correlated precisely with ophthalmic disorders known to us today because of the limited understanding of anatomy, function and pathophysiology that existed. However, De Oculis provides us with a glimpse of the practice of medicine in the Middle Ages.

Objectives: To characterize the pathogenesis and clinical features of optic disc edema associated with obstructive sleep apnea syndrome (SAS)., Methods: A series of 4 patients with SAS and papilledema (PE) underwent complete neuro-ophthalmologic evaluation and lumbar puncture. In 1 patient, continuous 24-hour intracranial pressure (ICP) monitoring was also performed., Results: All 4 patients had bilateral PE that was asymmetric in 2. Three patients had optic nerve dysfunction, asymmetric in 1, unilateral in 2. Daytime cerebrospinal fluid pressure measurements were within normal range. Nocturnal monitoring performed in one patient, however, demonstrated repeated episodes of marked ICP elevation associated with apnea and arterial oxygen desaturation., Conclusions: We propose that PE in SAS is due to episodic nocturnal hypoxemia and hypercarbia resulting in increased ICP secondary to cerebral vasodilation. In these individuals, intermittent ICP elevation is sufficient to cause persistent disc edema. These patients may be at increased risk for developing visual loss secondary to PE compared with patients with obesity-related pseudotumor cerebri because of associated hypoxemia. The diagnosis of SAS PE may not be appreciated because daytime cerebrospinal fluid pressure measurements are normal and because patients tend to present with visual loss rather than with symptoms of increased ICP.

Purpose: To evaluate the effects of unilateral, stereotactic, posteroventral pallidotomy on saccadic eye movements in patients with Parkinson disease (PD)., Methods: Eye movements of 31 patients with moderate to advanced PD were recorded with an infrared system 1 month before and 3 months after pallidotomy. Two kinds of saccade tasks were used: saccade tasks for eliciting visually guided saccades and saccade tasks for eliciting internally mediated saccades (memory-guided, predictive, and anti-saccades). Latency, accuracy, peak velocity, and other parameters of saccades were evaluated., Results: Internally mediated saccades were more impaired in patients with advanced PD compared with those with moderate PD. Pallidotomy did not affect visually guided saccades. After pallidotomy, the peak saccadic velocity of internally mediated saccades decreased., Conclusions: Hence, although pallidotomy has led to improvements in other motor functions, none were observed in saccadic responses. Rather, several modest decrements, below the level of clinical significance and all in internally mediated saccades, were observed.

Anatomic and neuronal recordings suggest that the nucleus reticularis tegmenti pontis (NRTP) of macaques may be a major pontine component of a cortico-ponto-cerebellar pathway that subserves the control of smooth-pursuit eye movements. The existence of such a pathway was implicated by the lack of permanent pursuit impairment after bilateral lesions in the dorsolateral pontine nucleus. To provide more direct evidence that NRTP is involved with regulating smooth-pursuit eye movements, chemical lesions were made in macaque NRTP by injecting either lidocaine or ibotenic acid. Injection sites first were identified by the recording of smooth-pursuit-related modulations in neuronal activity. The resulting lesions caused significant deficits in both the maintenance and the initiation of smooth-pursuit eye movements. After lesion formation, the gain of constant-velocity, maintained smooth-pursuit eye movements decreased, on the average, by 44%. Recovery of the ability to maintain smooth-pursuit eye movements occurred over approximately 3 days when maintained pursuit gains attained normal values. The step-ramp, "Rashbass" task was used to investigate the effects of the lesions on the initiation of smooth-pursuit eye movements. Eye accelerations averaged over the initial 80 ms of pursuit initiation were determined and found to be decremented, on the average, by 48% after the administration of ibotenic acid. Impairments in the initiation and maintenance of smooth-pursuit eye movements were directional in nature. Upward pursuit seemed to be the most vulnerable and was impaired in all cases independent of lesioning agent and type of pursuit investigated. Downward smooth pursuit seemed more resistant to the effects of chemical lesions in NRTP. Impairments in horizontal tracking were observed with examples of deficits in ipsilaterally and contralaterally directed pursuit. The results provide behavioral support for the physiologically and anatomic-based conclusion that NRTP is a component of a cortico-ponto-cerebellar circuit that presumably involves the pursuit area of the frontal eye field (FEF) and projects to ocular motor-related areas of the cerebellum. This FEF-NRTP-cerebellum path would parallel a middle and medial superior temporal cerebral cortical area-dorsolateral pontine nucleus-cerebellum pathway also known to be involved with regulating smooth-pursuit eye movements.

A 61-year-old woman had a 3-year history of imbalance. Eye movement studies revealed square-wave jerks, gaze paretic nystagmus, rebound nystagmus, impaired smooth pursuit, impaired optokinetic nystagmus, and abnormal fixation suppression of vestibular nystagmus. A brain magnetic resonance imaging study showed extensive areas of increased signal from the middle cerebellar peduncles and dentate nuclei, which enhanced with gadolinium. Histopathological analysis of a needle biopsy specimen of the left cerebellar peduncle revealed diffuse gliosis in the presence of symmetrically distributed areas of demyelination. There were associated Rosenthal fibers. Clinicopathologic correlation supported a diagnosis of Alexander disease. An adult patient with a history of progressive imbalance, ocular motility abnormalities consistent with cerebellar and/or brainstem dysfunction, and diffuse, symmetric hyperintense magnetic resonance imaging signals in brainstem and cerebellar white matter should suggest a diagnosis of adult-onset Alexander disease.

Purpose: The influence of genetic and prenatal environmental factors on characteristics of saccadic performance were evaluated in young monozygotic (MZ) twins (8-19 years old) of known chorion type., Methods: Saccadic eye movements were recorded using an infrared system. Saccadic latency, accuracy, and parameters of amplitude-peak velocity exponential equation (main sequence) were quantified., Results: Intraclass correlations of saccadic parameters differed significantly from zero for monochorionic and dichorionic MZ twins. The within-pair mean squares were significantly less, and intraclass correlations were significantly higher in monochorionic than in dichorionic twins for latency and were similar for other saccadic parameters (accuracy, slope of main sequence, and peak velocity for 15 degrees saccades)., Conclusions: These findings confirmed previous reports that saccadic parameters of MZ twins are significantly correlated and indicated that similarity of these parameters seen in MZ twins may be driven both by genetic and by prenatal environmental factors.

The objective of this article was to evaluate the etiologies, findings, and treatment of ocular neuromyotonia (ONM) in three case reports. The etiologies of ONM were determined by the histories, neuroradiologic tests, or biopsies. Clinical observations, videotaping, and electronic eye movement recordings documented the eye movement abnormalities. Intermittent diplopia developed several years after myelography with thorium dioxide (Thorotrast), radiation treatment for a pituitary tumor, and radiotherapy for medulloblastoma of the posterior fossa. All of the patients had intermittent, variable tropias that occurred spontaneously or were induced by eccentric gaze. One patient had a partial third nerve palsy, and another had a unilateral internuclear ophthalmoplegia (INO). ONM involved the paretic third nerve, extraocular muscles, and ipsilateral lateral rectus muscle in one patient, the paretic medial rectus muscle (INO) in one patient, a lateral rectus muscle (INO) in one patient, and a lateral rectus muscle in the last patient. Eye movement recordings were consistent with spasms of the involved muscles. Carbamazepine (Tegretol) abolished the ONM in two patients. The other patient had been taking carbamazepine for seizures and developed ONM when the dose was decreased. Increasing the dose abolished the ONM. ONM is an unusual cause of intermittent diplopia and strabismus, but its distinctive history and signs identify it easily. Damage to the peripheral cranial nerves might produce segmental demyelination, axonal hyperexcitability, and a self-perpetuating, reverberating circuit that causes spasms of the extraocular muscles.

Aims/background: To examine the effects of acupuncture at the sternocleidomastoid muscles on foveation characteristics in congenital nystagmus., Methods: Six patients with congenital nystagmus (CN) received a series of treatments consisting of two needles inserted into each sternocleidomastoid, stimulated by tapping gently every 5 minutes, for 20 minutes per session. Their eye movements were recorded using scleral search coils and changes in their CN waveforms analysed at each point in the treatment. Changes in the stability and duration of foveation periods were examined., Results: Four of the six patients showed improved foveation at the commencement of treatment; three maintained this response throughout the treatment period and after the needles were removed. In two, the CN waveform itself was modified., Conclusion: This study and others involving afferent stimulation to the neck and face suggest that projections from these areas to the reticular formation and vestibular nucleus may alter the behaviour of the pathophysiological mechanism underlying congenital nystagmus.

Purpose: The influence of genetic factors on characteristics of smooth pursuit were evaluated in young adult monozygotic (MZ) and dizygotic (DZ) twins before and after the administration of a single dose of ethanol., Methods: Sinusoidal pursuit was recorded using a scleral search coil at frequencies of 0.25 and 0.5 Hz before and after alcohol consumption. Pursuit gain, interval between saccades, saccadic accuracy, and saccadic amplitude were quantified., Results: Alcohol consumption reduced pursuit gain and saccadic accuracy and increased the rate and amplitude of saccades. Before and after alcohol consumption, the intraclass correlations for MZ twins (rMZ) were highly significant for pursuit gain, interval between saccades, and saccade amplitude. Corresponding correlations for DZ twins (rDZ) were not significant. Heritability values were similar before and after alcohol ingestion., Conclusions: The disparity between rMZ and rDZ suggests either multiple gene interactions or common environmental influences for MZ twins, greater than those for DZ twins.

1. Smooth pursuitlike eye movements were evoked with low current microstimulation delivered to rostral portions of the nucleus reticularis tegmenti pontis (rNRTP) in alert macaques. Microstimulation sites were selected by the observation of modulations in single-cell firing rates that were correlated with periodic smoothpursuit eye movements. Current intensities ranged from 10 to 120 microA and were routinely < 40 microA. Microstimulation was delivered either in the dark with no fixation, 100 ms after a fixation target was extinguished, or during maintained fixation of a stationary or moving target. Evoked eye movements also were studied under open-loop conditions with the target image stabilized on the retina. 2. Eye movements evoked in the absence of a target rapidly accelerated to a constant velocity that was maintained for the duration of the microstimulation. Evoked eye speeds ranged from 3.7 to 23 deg/s and averaged 11 deg/s. Evoked eye speed appeared to be linearly related to initial eye position with a sensitivity to initial eye position that averaged 0.23 deg.s-1.deg-1. While some horizontal and oblique smooth eye movements were elicited, microstimulation resulted in upward eye movements in 89% of the sites. 3. Evoked eye speed was found to be dependent on microstimulation pulse frequency and current intensity. Within limits, evoked eye speed increased with increases in stimulation frequency or current intensity. For stimulation frequencies < 300-400 Hz, only smooth pursuit-like eye movements were evoked. At higher stimulation frequencies, accompanying saccades consistently were elicited. 4. Feedback of retinal image motion interacted with the evoked eye movements to decrease eye speed if the visual motion was in the opposite direction as the evoked, pursuit-like eye movements. 5. The results implicate rNRTP as part of the neuronal substrate that controls smooth-pursuit eye movements. NRTP appears to be divided functionally into a rostral, pursuit-related portion and a caudal, saccade-related area. rNRTP is a component of a corticopontocerebellar circuit that presumably involves the pursuit area of the frontal eye field and that parallels the middle and medial superior temporal cerebral cortical/dorsalateral pontine nucleus (MT/MST-DLPN-cerebellum) pathway known to be involved also with regulating smooth-pursuit eye movements.

Purpose: To evaluate the degree of heritability in the latency, accuracy, and peak velocity of reflexive saccades in young adult monozygotic (MZ) and dizygotic (DZ) twins before and after the administration of a single dose of ethanol., Methods: Saccades were recorded using a scleral search coil before and after alcohol consumption, and data were analyzed offline. Estimates of heritability based in intraclass correlations (ICCs) and using a maximum likelihood estimates of genetic variance were calculated for the saccadic measures made before and after alcohol, as well as for the changes in latency, accuracy, and velocity., Results: Intraclass correlations for MZ twins (rMZ) were highly significant; those for DZ twins (rDZ) were not significantly different from zero. This disparity between rMZ and rDZ suggests either multiple gene interactions or in utero environmental differences in the MZ twins. Alcohol significantly prolonged latency, reduced accuracy, and lowered peak velocity. Although the changes after alcohol were not significant, heritability values increased in all three measures after alcohol administration., Conclusions: Latency, accuracy, and peak velocity appear to be controlled by multiple genes or to depend on prenatal environmental factors. Even a single low dose of alcohol appeared to enhance heritability measures. Differences seen between ICCs for latency, accuracy, and velocity after alcohol administration suggest that developmental control of the neural mechanisms underlying each measure may vary.

Purpose: Two cases illustrate the symptoms, signs, etiologies, and treatment of ocular neuromyotonia (ONM)., Methods: The histories, neuroradiologic tests, and/or biopsy revealed the etiologies of ONM in both patients. Clinical observations, videotaping, and electronic eye movement recordings documented the eye movements., Results: A 72-year-old man with chronic arachnoiditis following myelography with thorium dioxide (Thorotrast) developed intermittent diplopia and a partial right third nerve palsy. Left gaze induced spasm of the right medial rectus. Right gaze produced right lateral rectus spasm. A 66-year-old woman, who had radiation treatment for a pituitary tumor and acromegaly, had intermittent spasm of the left medial rectus muscle and left esotropia. The episodes occurred spontaneously and were induced by right gaze. A left internuclear ophthalmoplegia was also found. Carbamazepine (Tegretol) abolished the ONM in both patients., Conclusions: Although ONM is an unusual cause of intermittent diplopia and strabismus, its distinctive clinical features identify it. Injury to the peripheral cranial nerves probably leads to segmental demyelination, axonal hyperexcitability, and a self-perpetuating, reverberating circuit, which causes spasms of the extraocular muscles.

Although the range of normal ocular motor performance is broad, little is known about the sources of variability. Genetic transmission of eye movement deficits has been described but such possible control of normal function has been little investigated. Characteristics of smooth pursuit and saccades can be examined for the degree of concordance in related individuals. In this pilot study, we studied saccades and pursuit in eight monozygotic (MZ) twin pairs. The statistical analysis of the data used the intraclass correlation of MZ twins (rMZ) to estimate what fraction the covariance of the twin pairs was of the population variance. All saccadic measures showed significant MZ correlations (p < 0.05). Smooth pursuit gains were even more highly correlated (p < 0.001). These results indicate considerable similarity within pairs of twins, particularly for horizontal smooth pursuit, and suggest that larger studies on monozygotic and dizygotic twins would be desirable, to help separate out the relative contributions of environmental and genetic factors.

Two human subjects, who had no signs of other neurologic disorders, produced large amplitude, to-and-fro saccadic oscillations. One subject generated these oscillations intentionally. Eye movement recordings by DC electro-oculography and/or magnetic scleral search coil showed that the movements were bursts of conjugate saccades in opposing directions with no intersaccadic intervals. They were multidirectional (horizontal, vertical, or oblique), had amplitudes up to 40 degrees and had linear or curvilinear trajectories. These characteristics are similar to those of ocular flutter and opsoclonus in patients with brainstem and/or cerebellar disorders. Our observations show that fixation instabilities resembling ocular flutter and opsoclonus can be produced voluntarily.

Efficacy of optic nerve sheath decompression (ONSD) in treating non-arteritic ischemic optic neuropathy (NAION) is not clear. We retrospectively analyzed the records of 91 patients with NAION, who were examined during a two-year period, and compared the final Snellen visual acuities of eyes treated with ONSD with those of eyes that did not have surgery. Seven of 18 eyes with ONSD (39%) demonstrated increased visual acuity of two or more lines; whereas 23 of 71 eyes without surgery (32%) had increased acuity. The ONSD group and no surgery group were further subdivided into eyes with progressive visual loss and nonprogressive visual loss. No statistically significant differences in visual outcome between groups were found. We did not find the high frequency of visual improvement that has been reported in some studies of ONSD for NAION.

Objective: Growing interest in aggressive early management of rheumatoid arthritis (RA) with hydroxychloroquine (alone or in combination with other immunomodulating drugs) is reason to review current practices for monitoring ocular toxicity in patients who take antimalarial therapy., Methods: We surveyed by mail all ophthalmologists and rheumatologists in the State of Indiana about their practices in this regard., Results: Twenty-nine of 31 rheumatologists (94%) responded. All but one recommended ophthalmologic examinations every 6 months and 41% would leave the choice of testing procedures to the ophthalmologist. Fifty percent had discontinued hydroxychloroquine because of a patient's failure to make and/or keep an appointment with the ophthalmologist. Of 213 ophthalmologists surveyed, 150 (70%) responded. Seventy-nine percent recommended semiannual examinations. Funduscopy, visual acuity, and color vision tests were reported to be performed routinely. Eleven of 13 retina specialists (85%), but only 25% of 127 general ophthalmologists, would obtain macular photographs (p < 0.001). Forty-two percent of general ophthalmologists, compared with 8% of retina specialists, would perform computerized perimetry (p < 0.001). Recognition of retinal hyperpigmentation as a classic sign was surprisingly low in both groups. Concurrent review of the medical records of 24 patients with RA or systemic lupus erythematosus showed extremely variable followup intervals for ophthalmologic examination; 7 of the 24 patients had no record of an ophthalmologic evaluation., Conclusion: As interest in the early, aggressive management of RA continues to grow, significant education needs to be devoted to the monitoring and diagnosis of ocular toxicity of hydroxychloroquine by both rheumatologists and ophthalmologists.

We examined the relationship between visual loss and athletic performance and evaluated the visual classification system used in the 1988 United States Association of Blind Athletes (USABA) Summer Games. Athletes were asked about their age, sex, training, years of participation in organized competition, age at onset of blindness and were given an ophthalmologic exam that included Snellen acuity, contrast sensitivity, and visual fields. In the speed track events, visual class,* sex, age, hours of training, and years participating were found to have a positive correlation with performance. Visual class and sex were significant predictors of performance in the intermediate distance events; visual class was the only significant predictor of performance in the long distance events. Visual class, sex, age, and hours of training were correlated with performance in the track and field (throwing) events. Weightlifting performance was influenced by age and sex. The most consistent predictor of performance in the swimming events was the number of hours training per week. Our results indicate that the current classification system for visual loss is useful for grouping athletes for competition.

Four patients with congenital double elevator palsy were studied who had clinically brisk elevation of the affected eye from downgaze to the midline position of rest, but severely limited or absent elevation above primary position. Forced duction tests were negative and Bell's phenomenon was present preoperatively in all patients. To clarify why upgaze saccades clinically seemed intact below but not above midline, vertical saccadic velocities were measured using the scleral search coil technique. The tracings of three cases suggest sufficient superior rectus function to generate a normal upward saccadic trajectory. A supranuclear lesion is the most likely etiology of the inability to elevate the eye well above primary position in these three patients. In a fourth patient, the reduced ability to elevate the affected eye above primary position is caused by a superior rectus paresis with decreased upward saccadic velocities. We suggest at least three distinct groups of patients present clinically as double elevator palsy: primary inferior rectus restriction, primary superior rectus paresis or palsy, and congenital supranuclear elevation deficiency.

Gerstmann-Sträussler-Scheinker disease is a familial disorder of progressive ataxia and dementia in adulthood with extrapyramidal signs in some families. Neuro-ophthalmic examinations and eye movement recordings were performed in members of a large Indiana kindred. Five affected members and 11 members at risk were studied. Eye movements were recorded with videotape, electro-oculography, and/or magnetic scleral search coil. All affected members had abnormal eye movements characteristic of extrapyramidal diseases and cerebellar disorders. Nine members at risk had normal eye movements, but two others had slightly abnormal eye movements. Neuro-ophthalmic examination and eye movement recordings might be helpful in detecting early signs of Gerstmann-Sträussler-Scheinker disease in persons at risk.

Vertical saccadic velocities in 10 patients who had unilateral superior oblique muscle palsy and 14 normal subjects were measured with the magnetic scleral search coil. The authors sought to determine whether downward saccades in patients who had superior oblique palsy are slow. Peak velocities of 10 degrees and 20 degrees saccades performed in the superior and inferior fields of the orbit, and 10 degrees, 20 degrees, and 30 degrees saccades performed across the center of the orbit were recorded with the eye in center gaze, 30 degrees of adduction, and 30 degrees of abduction. Paired t-tests did not show statistically significant differences between upward and downward saccades in patients with superior oblique palsy; no effects of orbital field or position of horizontal gaze were found (P greater than 0.01). Comparison of similar saccades between normal subjects and patients with superior oblique palsy by two-sample t-tests did not show significant differences between the two groups (P greater than 0.01).

Eye-movement recordings may be helpful in the differentiation of Duane's syndrome from sixth-cranial-nerve palsy. Voluntary horizontal saccades were recorded and quantitated by electrooculography in 18 patients with unilateral type I Duane's syndrome and in 25 patients with sixth-nerve palsy. When ranges of abduction were matched, the peak velocities of abducting saccades in affected eyes were decreased equally in both groups. However, the peak velocities of adducting saccades in sound eyes were slowed in patients with Duane's syndrome. Because the standard deviations in saccadic velocities are large, computer-based, stepwise discriminant analyses were performed to identify the variables that proved to be useful in differentiating the two disorders. By entering these variables into the discriminant functions that were created, we could distinguish Duane's syndrome from sixth-nerve palsy in a statistically significant manner.

The analysis of vertical saccades by electrooculography (EOG) is limited by the presence of waveform artifacts that occur with both upward and downward saccades. The artifacts have been shown to increase the calculated velocities of upward saccades. For better evaluation of the nature of these artifacts, voluntary vertical saccades were recorded by EOG and magnetic search coil in five normal subjects and by EOG only in two patients who had previously undergone enucleation. All subjects demonstrated peaked EOG artifacts during vertical saccades. The amplitude of these artifacts was decreased but not completely eliminated by eyelid or eyeball fixation during the attempted saccade. Peak saccadic velocities were also decreased by eyelid fixation, but EOG measurements were generally less accurate than those obtained by search coil. There is evidence that these artifacts may be the result of a combination of eyelid electrical activity and resistance effects.

We describe 3 cases of Chiari type II malformation presenting with bilateral internuclear ophthalmoplegia (INO). Although prominent, the INO was not an isolated sign in any of the patients; superimposed abduction paresis was present in 2, and deficits in smooth pursuit, optokinetic nystagmus, and vestibulo-ocular responses were present in 3. Two had hydrocephalus: 1 was clinically unchanged without therapy after 5 years; the other did not improve with shunting. Findings in our 3 patients, along with the 4 previously reported, confirm that INO is 1 manifestation of widespread brainstem or cerebellar dysfunction. Its origin is probably multifactorial, related to hydrocephalus, vascular compromise, direct neuronal distortion, or congenital neural malformation.

1. In this study we sought to characterize the visual motion processing that exists in the dorsolateral pontine nucleus (DLPN) and make a comparison with the reported visual responses of the middle temporal (MT) and medial superior temporal (MST) areas of the monkey cerebral cortex. The DLPN is implicated as a component of the visuomotor interface involved with the regulation of smooth-pursuit eye movements, because it is a major terminus for afferents from MT and MST and also the source of efferents to cerebellar regions involved with eye-movement control. 2. Some DLPN cells were preferentially responsive to discrete (spot and bar) visual stimuli, or to large-field, random-dot pattern motion, or to both discrete and large-field visual motion. The results suggest differential input from localized regions of MT and MST. 3. The visual-motion responses of DLPN neurons were direction selective for 86% of the discrete visual responses and 95% of the large-field responses. Direction tuning bandwidths (full-width at 50% maximum response amplitude) averaged 107 degrees and 120 degrees for discrete and large-field visual motion responses, respectively. For the two visual response types, the direction index averaged 0.95 and 1.02, indicating that responses to stimuli moving in preferred directions were, on average, 20 and 50 times greater than responses to discrete or large-field stimulus movement in the opposite directions, respectively. 4. Most of the DLPN visual responses to movements of discrete visual stimuli exhibited increases in amplitude up to preferred retinal image speeds between 20 and 80 degrees/s, with an average preferred speed of 39 degrees/s. At higher speeds, the response amplitude of most units decreased, although a few units exhibited a broad saturation in response amplitude that was maintained up to at least 150 degrees/s before the response decreased. Over the range of speeds up to the preferred speeds, the sensitivity of DLPN neurons to discrete stimulus-related, retinal-image speed averaged 3.0 spikes/s per deg/s. The responses to large-field visual motion were less sensitive to retinal image speed and exhibited an average sensitivity of 1.4 spikes/s per deg/s before the visual response saturated. 5. DLPN and MT were quantitatively comparable with respect to degree of direction selectivity, retinal image speed tuning, and distribution of preferred speeds. Many DLPN receptive fields contained the fovea and were larger than those of MT and more like MST receptive fields in size.(ABSTRACT TRUNCATED AT 400 WORDS)

The clinical and histopathologic findings in two adults with craniopharyngioma emphasized the wide age range and diverse initial manifestations of this tumor. A retrospective clinical review of 49 additional patients substantiated these points and disclosed that over 40% were initially examined by ophthalmologists. The initial manifestations fell into four broad categories: (1) visual system abnormalities (77% of the cases), (2) headache (67%), (3) endocrinologic abnormalities (57%), and (4) mental status abnormalities (19%). The frequency of these manifestations varied slightly among different age groups. The radiologic features in the two patients described (a 75-year-old man and a 38-year-old woman) included a distinct appearance on computed tomographic scans. These craniopharyngioma were not calcified and were isodense without contrast but enhanced densely and uniformly with contrast, simulating an aneurysm of the circle of Willis.

In an attempt to define better the mechanism of impaired optokinetic nystagmus (OKN) caused by parietal lobe lesions, we recorded the eye movements of two patients. One had a slowly enlarging parietal glioma, and the other, an infarction involving the parietal and occipital lobes. In both patients, ipsilateral foveal pursuit and full-field pursuit of a surrounding optokinetic drum were impaired while voluntary and involuntary saccades (fast components) were normal. Foveal pursuit was impaired more than full-field pursuit, suggesting the existence of two separate pathways by which visual signals for OKN slow phases reach the oculomotor centers in the brainstem. We conclude that the ipsilateral slow phase OKN deficit seen in our patients resulted from damage to the foveal pursuit pathway that runs from the occipitoparietal association area to the ipsilateral brainstem horizontal gaze center.

Identical twins with congenital nystagmus were examined and studied with eye movement recordings and videotaping. The nystagmus differed in its location of the null zone, its frequency and amplitude, the degree of persistence in the dark, and the degree of impairment of pursuit and optokinetic nystagmus. As the two boys have the identical genetic constitution, we postulate that the discordant features of the nystagmus represent variable expressivity or, alternatively, the influence of environmental factors.

We studied electro-oculographic and videotape recordings of eye movements in six patients with Wallenberg's syndrome. With fixation, all patients had a spontaneous rotatory nystagmus with the fast phase directed toward the intact side. With loss of fixation, the patients' eyes deviated tonically toward the side of the lesion. Voluntary and involuntary saccades had larger amplitude when directed toward the side of the lesion than away from it. The spontaneous nystagmus predictably interacted with all slow eye movements, producing asymmetric smooth-pursuit, optokinetic, and vestibular responses. In addition, smooth-pursuit and optokinetic responses were decreased significantly in both directions compared to normal subjects. Fixation suppression of vestibular nystagmus also was impaired in both directions. We concluded that two different types of oculomotor bias were present in these patients--a velocity bias and a position bias. The former resulted from damage to the caudal lateral vestibular nuclei, and the latter from interruption of cerebellopontine pathways.