Two Electrical Engineers, One Problem, and Evolution Produced the Same Solution: A Historical Note.

This note adds historical context into solving the problem of improving the speed of the step response of a low-order plant in two different types of control systems, a chemical mixing system and the human saccadic system. Two electrical engineers studied the above problem: one to understand and model how nature and evolution solved it and the other to design a control system to solve it in a man-made commercial system. David A.

Foveation dynamics in congenital nystagmus IV: vergence.

Purpose: To evaluate foveation dynamics and characteristics of vergence eye movements during fixation of static targets at different distances and while tracking a target moving in depth in a subject with congenital nystagmus (CN).

Method: Eye movements of a well-studied subject with CN were recorded using the magnetic search coil technique and analyzed using the OMtools software, including the eXpanded Nystagmus Acuity Function (NAFX).

Results: Both the phase planes and NAFX values during fixation of targets at various near distances were equivalent to those during fixation of a far target.

Ocular Motor System Control Models and the Cerebellum: Hypothetical Mechanisms.

To review our studies and "top-down" models of saccadic intrusions and infantile nystagmus syndrome with the aim of hypothesizing areas of cerebellar connections controlling parts of the ocular motor subsystems involved in both types of function and dysfunction. The methods of eye-movement recording and modeling are described in detail in the cited references. Saccadic intrusions, such as square-wave jerks and square-wave oscillations, can be simulated by a single malfunction, whereas staircase saccadic intrusions required two independent malfunctions.

Longitudinal Studies and Eye-Movement-Based Treatments of Infantile Nystagmus Syndrome: Estimated and Measured Therapeutic Improvements in Three Complex Cases.

Introduction And Purpose: To demonstrate the utility of using eye-movement data to reveal the diagnostic characteristics of infantile nystagmus syndrome (INS), determine treatment, and both estimate and document therapeutic improvements in three patients with well-developed foveation periods, fairly broad, lateral gaze "nulls," head turns, strabismus, and complex, multiplanar nystagmus.

Patients And Methods: Infrared reflection, magnetic search coil, and high-speed digital video systems were used to record the eye movements of INS patients, pre- and post-Kestenbaum null-point correction surgery (horizontal or vertical). Data were analyzed and estimations made, using the eXpanded Nystagmus Acuity Function (NAFX) that is part of the OMtools toolbox for MATLAB.

Clinical and ocular motor complications of extraocular muscle extirpation for infantile nystagmus syndrome.

Purpose: To describe the effects of extraocular muscle extirpation performed after previous eye muscle surgery in a 20-year-old woman with infantile nystagmus syndrome (INS) for whom we have 19 years of follow-up data.

Methods: Clinical examinations were performed. Eye movement data analysis was carried out using the eXpanded Nystagmus Acuity Function (NAFX) and longest foveation domain (LFD).

Development and surgical removal of an epiretinal membrane in infantile nystagmus syndrome: a new type of oscillopsia.

Purpose: To report and discuss a focal oscillopsia in a small area of the visual field produced by, and after the removal of, an epiretinal membrane (ERM) in an individual with infantile nystagmus syndrome (INS) since birth with no associated afferent visual deficits.

Study Design: A retrospective case report.

Methods: A chart review, including clinical and electrophysiological data.

Effects of augmented tenotomy and reattachment in the infantile nystagmus syndrome.

Purpose: To test the hypothesis that augmented tenotomy and reattachment surgery (AT-R), which involves placing an additional suture in each distal tendon during the 4-muscle tenotomy and reattachment (T-R) or other infantile nystagmus syndrome (INS) procedures, could increase the beneficial effects of many types of extraocular muscle (EOM) surgery to treat INS.

Methods: Both infrared reflection and high-speed digital video systems were used to record the eye movements in 4 patients with INS before and after AT-R surgery. Data were analyzed using the eXpanded Nystagmus Acuity Function (NAFX) that is part of the OMtools software.

Emergency department visits with facial fractures among children and adolescents: an analysis of profile and predictors of causes of injuries.

Purpose: The objectives of this study were to provide nationally representative estimates of hospital-based emergency department (ED) visits for facial fractures in children and adolescents, examine the burden associated with such visits, identify common types of facial fracture, and examine the role of patient-related demographic factors on the causes of facial fractures.

Materials And Methods: The Nationwide Emergency Department Sample for 2008 to 2010 was used. All ED visits with a diagnosis of facial fractures in those no older than 21 years were selected.

The effect of walking on postprandial glycemic excursion in patients with type 1 diabetes and healthy people.

Objective: Physical activity (PA), even at low intensity, promotes health and improves hyperglycemia. However, the effect of low-intensity PA captured with accelerometery on glucose variability in healthy individuals and patients with type 1 diabetes has not been examined. Quantifying the effects of PA on glycemic variability would improve artificial endocrine pancreas (AEP) algorithms.

A decade post WHI, menopausal hormone therapy comes full circle--need for independent commission.

The sudden decision by the National Heart, Lung, and Blood Institute of the National Institutes of Health to terminate the estrogen-progestogen therapy arm of the Women's Health Initiative (WHI) Study a decade ago now begs two questions:--has women's health after menopause been helped or harmed as a result of the findings and the way in which they were presented, and, if harmed, what needs to be done to put things right? Time and multiple reviews of specific publications from the WHI lead to the serious question whether a project designed to be of benefit to women's health has boomeranged, and instead may have resulted in significant impairment to both the quality of life and physical health of postmenopausal women. It is therefore urgent to confirm whether this is so and whether corrective action needs be taken to prevent even more harm. There are two obvious and immediate actions to be called for: (1) The Food and Drug Administration (FDA) needs to revisit the black-box warnings on postmenopausal hormones.

The mechanism of oscillopsia and its suppression.

We studied the mechanisms of oscillopsia suppression in subjects with infantile nystagmus syndrome, fusion maldevelopment nystagmus syndrome, and acquired nystagmus (AN). Hypothetical possibilities for perceptual stability were the following: (1) epochs of clear and stable vision during foveation periods of nystagmus waveforms; (2) cancellation by efference copy of motor output; (3) a combination of the effects of both foveation-period stability and efference-copy cancellation; or (4) elevated motion-detection threshold and vision suppression. Observations, studies, and models of oscillopsia suppression allowed comparison of these possibilities.

The role of traditional healers in community-based HIV care in rural Lesotho.

Traditional healers provide a substantial proportion of health care in resource-poor settings, including countries with high burdens of HIV in sub-Saharan Africa. Traditional healers have played many roles in HIV care, but some biomedical providers view them as obstacles in providing HIV treatment. This is a qualitative study exploring the roles played by traditional healers in a community-based program rolling out antiretroviral therapy (ART) in two rural communities in Lesotho.

Effects of acetazolamide on infantile nystagmus syndrome waveforms: comparisons to contact lenses and convergence in a well-studied subject.

Aim: To determine if acetazolamide, an effective treatment for certain inherited channelopathies, has therapeutic effects on infantile nystagmus syndrome (INS) in a well-studied subject, compare them to other therapies in the same subject and to tenotomy and reattachment (T&R) in other subjects.

Methods: Eye-movement data were taken using a high-speed digital video recording system. Nystagmus waveforms were analyzed by applying an eXpanded Nystagmus Acuity Function (NAFX) at different gaze angles and determining the Longest Foveation Domain (LFD).

Two hypothetical nystagmus procedures: augmented tenotomy and reattachment and augmented tendon suture (Sans tenotomy).

Purpose: To review the hypothetical mechanism and therapeutic benefits of the four-muscle tenotomy and reattachment (T&R) procedure using knowledge accrued over the 10 years since its proposal; to describe an augmented tendon suture (ATS) technique to improve the procedure based on one of the originally suggested alternative methods (mechanical); and to hypothesize a new ATS procedure to achieve the same therapeutic benefits without extraocular muscle tenotomy or reattachment to the globe.

Methods: Standard surgical methods were used.

Results: The T&R procedure damps and improves infantile nystagmus syndrome (INS) waveforms, improves eXtended Nystagmus Acuity Function (NAFX) values, broadens the NAFX peak versus gaze angle, and damps slow eye movements but not saccades.

Infantile nystagmus syndrome: Broadening the high-foveation-quality field with contact lenses.

We investigated the effects of contact lenses in broadening and improving the high-foveation-quality field in a subject with infantile nystagmus syndrome (INS). A high-speed, digitized video system was used for the eye-movement recording. The subject was asked to fixate a far target at different horizontal gaze angles with contact lenses inserted.

Eye-movement-based assessment of visual function in patients with infantile nystagmus syndrome.

Purpose: Infantile Nystagmus Syndrome (INS) is an ocular motor system dysfunction characterized by the rhythmic to-and-fro oscillations of the eyes. Traditionally, the assessment of INS visual function solely focused on null- or primary-position visual acuity. Our purpose is to use the past four decades of INS research to introduce a more complete assessment of visual function in patients with INS.

Extending the eXpanded Nystagmus Acuity Function for vertical and multiplanar data.

We updated and extended the functionality of the eXpanded Nystagmus Acuity Function (NAFX), for application under more diverse circumstances, improving its clinical predictive value. The original NAFX "tau-surface" of minimum-necessary-foveation times had been individually calculated for each combination of position and velocity limits. We have replaced it with an idealized mathematical function that repairs the irregularities in its surface due to idiosyncrasies in the subject data used for the initial calculations.

Factors influencing pursuit ability in infantile nystagmus syndrome: Target timing and foveation capability.

We wished to determine the influential factors for Infantile Nystagmus Syndrome (INS) subjects' ability to acquire and pursue moving targets using predictions from the behavioral Ocular Motor System (OMS) model and data from INS subjects. Ocular motor simulations using a behavioral OMS model were performed in MATLAB Simulink. Eye-movement recordings were performed using a high-speed digital video system.

Extraocular proprioception and new treatments for infantile nystagmus syndrome.

Our goal is to develop the proprioceptive hypothesis for nystagmus damping; and present the resulting therapies for the treatment of infantile nystagmus syndrome (INS) and acquired nystagmus. Contact lenses, cutaneous stimulation, and neck-muscle vibration damped INS. Four-muscle tenotomy and reattachment was hypothesized as a treatment for INS in 1979 and successfully demonstrated to improve foveation in a canine model of INS and seesaw nystagmus in 1998 and in humans with INS (masked-data, NEI Clinical Trial) in 2003.

Computer-assisted neurosurgery.

Computer-assisted neurosurgery has become so successful that it is rapidly becoming indistinguishable from, quite simply, neurosurgery. This trend promises to accelerate over the next several decades, bringing considerable benefit to the patients we care for. From a pragmatic point of view, can we identify specific instances in which clinical practice has been altered by computer assistance? During craniotomies for the resection of brain tumors, this technology has led to a greater standardization within and among practitioners for the expected degree of resection and the risk of morbidity and mortality.

Being "slow to see" is a dynamic visual function consequence of infantile nystagmus syndrome: model predictions and patient data identify stimulus timing as its cause.

The objective of this study was to investigate the dynamic properties of infantile nystagmus syndrome (INS) that affect visual function; i.e., which factors influence latency of the initial reflexive saccade (Ls) and latency to target acquisition (Lt).

Potentially life-threatening sleep apnea is unrecognized without aggressive evaluation.

Background: Many patients undergoing bariatric surgery have severe comorbidities, including obstructive sleep apnea (OSA). We suspected that sleep apnea was underdiagnosed in our study population.

Methods: A retrospective chart review of our bariatric database was conducted comparing OSA evaluation based on clinical parameters (Era 1) with mandatory OSA evaluation for all patients (Era 2).

Combining recessions (nystagmus and strabismus) with tenotomy improved visual function and decreased oscillopsia and diplopia in acquired downbeat nystagmus and in horizontal infantile nystagmus syndrome.

Purpose: To investigate the effects of combined tenotomy and recession procedures on both acquired downbeat nystagmus and horizontal infantile nystagmus.

Methods: Patient 1 had downbeat nystagmus with a chin-down (upgaze) position, oscillopsia, strabismus, and diplopia. Asymmetric superior rectus recessions and inferior rectus tenotomies reduced right hypertropia and rotated both eyes downward.

"Staircase" saccadic intrusions plus transient yoking and neural integrator failure associated with cerebellar hypoplasia: a model simulation.

We present hypothesized ocular motor mechanisms of unique "staircase-like" sequences of saccadic intrusions in one direction that we have named, "staircase saccadic intrusions (SSI)," square-wave jerks/oscillations (SWJ/SWO), and transient failures of yoking and neural integrators in a patient with severe hypotonia, ataxic speech, motor and language developmental delays, and torticollis (Joubert syndrome). Brain magnetic resonance imaging showed hypoplasia of the cerebellar vermis and inferior cerebellar peduncles, abnormal superior cerebellar peduncles with deepening of the interpeduncular fossa, and enlargement of the fourth ventricle. During far and near fixation and smooth pursuit (rightward markedly better than leftward), the subject exhibited conjugate SSI (rightward more than leftward, with intersaccadic intervals equivalent to the normal 250 msec visual latency), SWJ, SWO, and uniocular, convergent and divergent saccades (including double saccades).