The vertical computerized rotational head impulse test.

The computerized rotational head impulse test (crHIT) uses a computer-controlled rotational chair to deliver whole-body rotational impulses to assess the semicircular canals. The crHIT has only been described for horizontal head plane rotations. The purpose of this study was to describe the crHIT for vertical head plane rotations. In this preliminary study, we assessed four patients with surgically confirmed unilateral peripheral vestibular abnormalities and two control subjects. Results indicated that the crHIT was well-tolerated for both horizontal head plane and vertical head plane stimuli. The crHIT successfully assessed each of the six semicircular canals. This study suggests that the crHIT has the potential to become a new laboratory-based vestibular test for both the horizontal and vertical semicircular canals.

Frequency dependence of coordinated pupil and eye movements for binocular disparity tracking.

Introduction: Coordinated alignment of the eyes during gaze fixation and eye movements are an important component of normal visual function. We have previously described the coordinated behavior of convergence eye movements and pupillary responses using a 0.1 Hz binocular disparity-driven sine profile and a step profile. The goal of this publication is to further characterize ocular vergence-pupil size coordination over a wider range of frequencies of ocular disparity stimulation in normal subjects. Methods: Binocular disparity stimulation is generated by presentation of independent targets to each eye on a virtual reality display, while eye movements and pupil size are measured by an embedded video-oculography system. This design allows us to study two complimentary analyses of this motion relationship. First, a macroscale analysis describes the vergence angle of the eyes in response to binocular disparity target movement and pupil area as a function of the observed vergence response. Second, a microscale analysis performs a piecewise linear decomposition of the vergence angle and pupil relationship to permit more nuanced findings. Results: These analyses identified three main features of controlled coupling of pupil and convergence eye movements. First, a near response relationship operates with increasing prevalence during convergence (relative to the "baseline" angle); the coupling is higher with increased convergence in this range. Second, the prevalence of "near response"-type coupling decreases monotonically in the diverging direction; the decrease persists after the targets move (converge back) from maximum divergence toward the baseline positions, with a minimum prevalence of near response segments near the baseline target position. Third, an opposite polarity pupil response is infrequent, but tends to be more prevalent when the vergence angles are at maximum convergence or divergence for a sinusoidal binocular disparity task. Discussion: We suggest that the latter response is an exploratory "range-validation" when binocular disparity is relatively constant. In a broader sense, these findings describe operating characteristics of the near response in normal subjects and form a basis for quantitative assessments of function in conditions such as convergence insufficiency and mild traumatic brain injury.

Statistical Considerations for Subjective Visual Vertical and Subjective Visual Horizontal Assessment in Normal Subjects.

Objectives: Judgments of the subjective visual vertical (SVV) and subjective visual horizontal (SVH) while seated upright are commonly included in standard clinical test batteries for vestibular function. We examined SVV and SVH data from retrospective control to assess their statistical distributions and normative values for magnitudes of the preset effect, sex differences, and fixed-head versus head-free device platforms for assessment. Methods: Retrospective clinical SVV and SVH data from 2 test platforms, Neuro-otologic Test Center (NOTC) and the Neurolign Dx 100 (I-Portal Portable Assessment System Nystagmograph) were analyzed statistically (SPSS and MATLAB software) for 408 healthy male and female civilians and military service members, aged 18-50 years. Results: No prominent age-related effects were observed. The preset angle effects for both SVV and SVH, and their deviations from orthogonality, agree in magnitude with previous reports. Differences attributable to interactions with device type and sex are of small magnitude. Analyses confirmed that common clinical measure for SVV and SVH, the average of equal numbers of clockwise and counterclockwise preset trials, was not significantly affected by the test device or sex of the subject. Finally, distributional analyses failed to reject the hypothesis of underlying Gaussian distributions for the clinical metrics. Conclusions: z scores based on these normative findings can be used for objective detection of outliers from normal functional limits in the clinic.

The landscape of medical care consumption in Israel: a nationwide population cross-sectional study.

BACKGROUND: The Ecology of medical care was first published in 1961. The graphical square model showed that 75% of the population in the US and England experience a feeling of illness during a given month, 25% seek medical help and only one percent are hospitalized. In 2001, Green and colleagues found the same findings despite the many changes that occurred over the past decades. The frequency of illness, the desire for assistance and the frequency of seeking and getting medical assistance may differ in different populations due to cultural, economic, social, demographic background and local Health policy. This work describes the ecology of medical care consumption in Israel for the first time and examines the socio-demographic effects on consumption. METHODS: This is a Nationwide cross-sectional study. A telephone survey was conducted among a representative sample of the adult population (> 15 years) in Israel. Subjective morbidity rate in the preceding month, the rate of those considering medical assistance and those who got assistance were calculated. Correlation between socio-demographic variables and patterns of morbidity and medical care consumption was examined using a t-test and chi square for continuous quantitative and categorical variables. Logistic regression was used for multivariate analysis. RESULTS: A total of 1862 people participated; 49.5% reported having symptoms in the previous month, 45% considered seeking medical advice, 35.2% sought out medical assistance and only 1.5% were hospitalized. The vast majority chose to contact their family physician (58%) and the primary care setting provided their needs in 80% of the cases; Subjective morbidity and medical care consumption differed significantly between Israeli Jews and Arabs. Gaps in the availability of medical services were observed as residents of the periphery forewent medical services significantly more than others (OR = 1.42, p = 0.026). CONCLUSIONS: Subjective morbidity is less common in Israel than in other countries, but paradoxically consumption of medical services is higher. An Israeli who feels ill will usually consider receiving assistance and will indeed receive assistance in most cases. However, a greater tendency to forego medical services in the periphery indicates barriers and inequality in the provision of health services. Different cultural perceptions, lack of knowledge and low accessibility to medical services in the periphery probably contribute to the contrast shown between low consumption of medical services and high prevalence of chronic illness in Arab society. The prevailing preference for family medicine and its ability to deal with most requests for assistance suggest that strengthening family medicine in the periphery may reduce those barriers and inequalities.

Portable eye-tracking as a reliable assessment of oculomotor, cognitive and reaction time function: Normative data for 18-45 year old.

Eye movements measured by high precision eye-tracking technology represent a sensitive, objective, and non-invasive method to probe functional neural pathways. Oculomotor tests (e.g., saccades and smooth pursuit), tests that involve cognitive processing (e.g., antisaccade and predictive saccade), and reaction time tests have increasingly been showing utility in the diagnosis and monitoring of mild traumatic brain injury (mTBI) in research settings. Currently, the adoption of these tests into clinical practice is hampered by a lack of a normative data set. The goal of this study was to construct a normative database to be used as a reference for comparing patients' results. Oculomotor, cognitive, and reaction time tests were administered to male and female volunteers, aged 18-45, who were free of any neurological, vestibular disorders, or other head injuries. Tests were delivered using either a rotatory chair equipped with video-oculography goggles (VOG) or a portable virtual reality-like VOG goggle device with incorporated infrared eye-tracking technology. Statistical analysis revealed no effects of age on test metrics when participant data were divided into pediatric (i.e.,18-21 years, following FDA criteria) and adult (i.e., 21-45 years) groups. Gender (self-reported) had an effect on auditory reaction time, with males being faster than females. Pooled data were used to construct a normative database using 95% reference intervals (RI) with 90% confidence intervals on the upper and lower limits of the RI. The availability of these RIs readily allows clinicians to identify specific metrics that are deficient, therefore aiding in rapid triage, informing and monitoring treatment and/or rehabilitation protocols, and aiding in the return to duty/activity decision. This database is FDA cleared for use in clinical practice (K192186).

Normative data for ages 18-45 for ocular motor and vestibular testing using eye tracking.

OBJECTIVE: Eye tracking technology has been employed in assessing ocular motor and vestibular function following vestibular and neurologic conditions, including traumatic brain injury (TBI). Assessments include tests that provide visual and motion (rotation) stimuli while recording horizontal, vertical, and torsional eye movements. While some of these tests have shown diagnostic promise in previous studies, their use in clinical practice is limited by the lack of normative data. The goal of this study was to construct normative reference ranges to be used when comparing patients' results. METHODS: Optokinetic response, subjective visual horizontal and vertical, and rotation tests were administered to male and female volunteers, ages 18-45, who were free from neurological, vestibular disorders, or other head injuries. Tests were administered using either a rotatory chair or a portable virtual reality-like goggle equipped with video-oculography. RESULTS: Reference values for eye movements in response to different patterns of stimuli were analyzed from 290 to 449 participants. Analysis of gender (self-reported) or age when grouped as pediatric (late adolescent; 18-21 years of age) and adult (21-45 years of age) revealed no effects on the test metrics. Data were pooled and presented for each test metric as the 95% reference interval (RI) with 90% confidence intervals (CI) on upper and lower limits of the RI. CONCLUSIONS: This normative database can serve as a tool to aid in diagnosis, treatment, and/or rehabilitation protocols for vestibular and neurological conditions, including mild TBI (mTBI). This database has been cleared by the FDA for use in clinical practice (K192186). LEVEL OF EVIDENCE: 2b.

Distinctive Convergence Eye Movements in an Acquired Neurosensory Dysfunction.

In late 2016, diplomats in Havana, Cuba, began presenting with a unique symptom complex after perceiving a strange noise and/or feeling a pressure field in their domicile. This report is a retrospective, quantitative analysis of video-oculography data of pupillary light reflex performance and binocular disparity-driven eye and pupil movements during the acute time period after the reported exposure. The patterns of response in these 19 individuals are markedly different than those seen in a group of individuals with the usual acute mild traumatic brain injury (17 subjects) and from 62 control subjects (21-60 years old) with no injury. Non-linear least squares regression was used to estimate the model parameters from the eye movement and the pupil measurements (1). Linear discriminant analysis was then used to identify a classifier for an objective discrimination of the groups with >91% accuracy and no confusion between the acute neurosensory findings among the members of the Havana diplomatic community and the subjects with acute mild traumatic brain injury. This pattern difference in eye and pupil behavior may be a useful screen to help objectively distinguish blunt trauma from Havana-type effects in the future and to guide the affected individuals to appropriate care.

Does Physician's Training Induce Overconfidence That Hampers Disclosing Errors?

PURPOSE: Although transparency is critical for reducing medical errors, physicians feel discomfort with disclosure. We explored whether overconfidence relates to physician's reluctance to admit that an error may have occurred. METHOD: At 3 university medical centers, a survey presented a clinical vignette of a girl with urinary infection and penicillin allergy to medical students and physicians, asking them to rate their level of confidence for each step of the diagnosis and management. After anaphylaxis develops after cephalosporin administration, respondents were asked about their willingness to admit that an error might have occurred and to rate their level of discomfort in doing so. We analyzed levels of confidence, accuracy, willingness to admit mistake, and discomfort. RESULTS: Respondents reported high levels of confidence for their answers to the questions of diagnosis and management, even when wrong-indicating miscalibration of confidence and accuracy. Compared with students, physicians had significantly higher levels of confidence, lower accuracy, and lower willingness to admit mistake. Although most respondents agreed in principle that errors should be disclosed, in the presented case, significantly less agreed to admit that a mistake might have occurred or to say so explicitly to the family. An association was found between overconfidence and discomfort with disclosure. CONCLUSIONS: Our study shows overconfidence associated with clinician's training and with reluctance to admit mistake, suggesting a contributing role to the difficulty in leveraging safety events into quality improvement. Training physicians to have both knowledge and adequate self-doubt is an educational challenge.

Neurosensory Symptom Complexes after Acute Mild Traumatic Brain Injury.

Mild Traumatic Brain Injury (mTBI) is a prominent public health issue. To date, subjective symptom complaints primarily dictate diagnostic and treatment approaches. As such, the description and qualification of these symptoms in the mTBI patient population is of great value. This manuscript describes the symptoms of mTBI patients as compared to controls in a larger study designed to examine the use of vestibular testing to diagnose mTBI. Five symptom clusters were identified: Post-Traumatic Headache/Migraine, Nausea, Emotional/Affective, Fatigue/Malaise, and Dizziness/Mild Cognitive Impairment. Our analysis indicates that individuals with mTBI have headache, dizziness, and cognitive dysfunction far out of proportion to those without mTBI. In addition, sleep disorders and emotional issues were significantly more common amongst mTBI patients than non-injured individuals. A simple set of questions inquiring about dizziness, headache, and cognitive issues may provide diagnostic accuracy. The consideration of other symptoms may be critical for providing prognostic value and treatment for best short-term outcomes or prevention of long-term complications.

The horizontal computerized rotational impulse test.

Whole-body impulsive rotations were used to overcome several limitations associated with manual head impulse testing. A computer-controlled rotational chair delivered brief, whole-body, earth-vertical axis yaw impulsive rotations while eye movements were measured using video-oculography. Results from an unselected group of 20 patients with dizziness and a group of 22 control subjects indicated that the horizontal computerized rotational head impulse test (crHIT) is well-tolerated and provides an estimate of unidirectional vestibulo-ocular reflex gain comparable to results from caloric testing. This study demonstrates that the horizontal crHIT is a new assessment tool that overcomes many of the limitations of manual head impulse testing and provides a reliable laboratory-based measure of unilateral horizontal semicircular canal function.

Subjective visual vertical (SVV) patterns obtained using different translation times during unilateral centrifugation (UC) testing.

BACKGROUND: Unilateral centrifugation (UC) is a test of utricular function that involves the eccentric displacement of a patient while undergoing high velocity rotation. These off-center placements permit evaluation of utricles as only one organ is subjected to linear stimulation. Currently, several different protocols are used for translation times between positions (e.g., Clarke et al, 1996; Wuyts et al, 2003). PURPOSE: This study examined the effects of different translation times between eccentric and centric positions during UC on an individual's perceived subjective visual vertical (SVV). RESEARCH DESIGN: A prospective repeated measures design was used in this study. STUDY SAMPLE: Forty-three young adults with no history or complaints of vestibular or neurological disorders participated in this study. DATA COLLECTION: All testing was performed on a Neuro Kinetics Inc. (Pittsburgh, PA) Neuro-Otologic Test Center (NOTC) rotational chair at the Bloomsburg University of Pennsylvania Vestibular Clinic. Each participant completed six SVV trials in the static condition (sSVV) as a baseline of function. In addition, each participant completed UC trials using a rotational velocity of 300°/sec with 4 cm eccentric lateral displacements that were maintained for 60 sec per position. Translations of 5, 10, 15, 20, 25, and 30 sec were randomized. The maximum velocity was maintained for 90 sec prior to the eccentric placement. Multiple estimations of dynamic subjective visual vertical (dSVV) were performed for each position. RESULTS: dSVV data yielded several trends. At 5 sec translations, dSVV values had greater variability and required longer for participant responses to stabilize. Regardless of UC translation time, initial trial values were often quite different from the remaining trials. Shorter UC translation times were associated with more eccentric dSVV values outside of the clinical norms. While not statistically significant, more variance was associated with the shortest UC translation times, while 15 and 25 sec translation data demonstrated the best correlations and lowest variances. DISCUSSION: Findings suggest that incorporating sSVV data to normalize dSVV data should be considered to reduce the influence of the underlying baseline static otolithic function on the UC results. The presence of a clear tendency for shorter UC translation times to be associated with larger numbers of clinically abnormal findings may indicate that very short UC translation times may not be ideal for clinical applications. This is supported by our finding that longer UC translation times elicited more consistent SVV results and less response variability. While some of these findings were not statistically significant, the results do suggest that clinical UC testing may benefit from optimization of translation time as well as inclusion of sSVV in response interpretation.

Unexplained complaints in primary care: evidence of action bias.

PURPOSE: Primary care physicians sometimes encounter patients with clinical complaints that do not fit into a recognized diagnostic pattern. This study was undertaken to assess the way physicians respond to patients whose symptoms are unusual or unexplained that is, what approach they take in the absence of a working hypothesis. METHODS: We surveyed 130 primary care physicians affiliated with 3 academic centers in Israel, presenting 5 clinical vignettes describing patients who had unusual complaints, no clear diagnosis, and no apparent need for urgent care. We asked physicians to provide the most likely diagnosis for each case and to rate their level of confidence in that diagnosis;respondents were also asked to provide a management strategy for each case and their level of confidence in the chosen approach. Finally, we asked the physicians to estimate how many of their own patients have presentations similar to the individuals in the clinical vignettes. RESULTS: Physicians proposed, on average, 22 diagnoses for each case. Most indicated that they would choose action (testing, consulting, sending the patient to the emergency department, or prescribing) rather than follow-up only (87% vs 13%; P<.01). Respondents' confidence in the management approach they had chosen for all the cases was higher than their confidence in the diagnoses (5.6 vs 4.3, respectively, on a scale of1-10; P<.001). Physicians estimated that 10% to 20% of the patients they see in their practice have unusual or unexplained symptoms that are difficult to diagnose. CONCLUSION: Uncertain diagnosis is a regular challenge for primary care physicians. In such cases, we found that physicians prefer a workup to follow-up, an inclination consistent with"action bias."

An eye for a tooth.

OBJECTIVE: To propose a possible link between dental extraction and intra-ocular complications. BACKGROUND: Several publications in medical literature describe intra-ocular complications after different dental procedures. RESULTS: Retinal detachment and vitreous hemorrhage following dental extraction with an appropriate anesthesia. CONCLUSION: Systemic complications following dental treatments should not be neglected and proper medical treatment must be provided as soon as possible.

Comparative regional pupillography as a noninvasive biosensor screening method for diabetic retinopathy.

PURPOSE: We describe infrared regional pupillometry as an objective comparative assessment of midperipheral to central retinal sensitivity and to correlate with midperipheral retinal ischemia in diabetic subjects. METHODS: We tested 12 normal and 17 diabetic subjects using bilateral infrared pupillometry. The diabetic cohort included seven subjects without, five with mild, three with moderate, and two with severe non-proliferative diabetic retinopathy (NPDR). Central and annular stimuli of varying intensity were presented to one eye, and pupillary amplitude and constriction velocity were measured from both eyes. Light stimulus of increasing intensity was presented as 20 consecutive trials (stimulus duration of 300 ms with 3000 ms intervals). The ratio of central to peripheral responses (Q values) was calculated for each stimulus configuration. Average responses with respect to the stimulus strength were regressed with Gompertz sigmoid function. RESULTS: Control and moderate/severe NPDR cases comparison showed statistically significant differences in amplitude (Q(A)) and constriction velocity (Q(CV)) (Wilcoxon rank sum test P = 0.002, respectively). Age difference for these groups was not statistically significant (Wilcoxon rank sum test P = 0.15). The comparison of control and diabetic subjects without NPDR/mild NPDR was statistically significant for Q(A) and Q(CV) (Wilcoxon rank sum test P = 0.0002 and P = 0.001, respectively). Q(A) and Q(CV) differences were statistically significant between moderate/severe NPDR cases and subjects without or mild NPDR cases (Wilcoxon rank sum test P = 0.013). CONCLUSIONS: Q(A) and Q(CV) values correlated highly with the severity of diabetic retinopathy, but not with the duration of diabetes.

The effect of brushing on hair loss in women.

BACKGROUND: Hair loss is a common, bothersome problem among women. OBJECTIVE: To evaluate the effect of different brushing frequencies on hair loss in women. METHODS: This was a non-randomized crossover study. During a 4-week period, 14 women were asked to brush their hair with different frequencies during each of the 4 weeks. The amount of hairs lost during each week was counted and the average hairs lost during each week was compared with that of a week with a different brushing frequency. RESULTS: In all comparisons analyzed, hair loss was reduced by reducing brushing frequency. A subgroup analysis found strong association (p < 0.05) between brushing frequencies and the magnitude of hair loss. A limitation of the study was that the majority of the subgroup analyses did not find a statistically significant association between brushing frequency and amount of hair lost. CONCLUSION: Brushing is associated with hair loss. Reducing the brushing frequencies may reduce the amount of hair shed.

Declining frequency of liver enzyme abnormalities with statins: experience from general practice in Jerusalem.

OBJECTIVE: Safety data of statins have been collected from diverse ethnic populations. Drug effects, including adverse reactions, may depend on genetics and environment. We investigated liver enzymes in relation to statin treatment in a northeast Jerusalem Jewish community. METHODS: A long-term laboratory follow-up of liver enzymes prestatin and poststatin introduction was conducted. Records of participants who received statins were reviewed. Prestatin and poststatin liver enzymes were compared by various statistical models. RESULTS: Two-hundred and sixty participants had mean follow-up of 25 months prestatin, and 26 months poststatin introduction. Sixty-six percent had hypertension, and 48% were diabetic. The frequency of liver enzyme abnormalities varied widely with time. Altogether, during pretreatment and posttreatment follow-up, 18.4 and 13.4% of measurements revealed abnormal (either cholestatic and/or hepatocellular) liver enzymes, respectively (P<0.01). Hyperlipidemia (positive correlation) and administration of renin-angiotensin antagonists (inverse correlation) predicted on-treatment liver enzyme abnormalities in men, whereas diabetes predicted abnormalities in women. CONCLUSION: A substantial proportion of patients who need statins had elevated 'background' liver enzymes. The profile of elevated liver enzymes was not augmented by statin therapy; moreover, statin administration was associated with a decreasing frequency of liver enzyme abnormalities. Physicians should not refrain from prescribing statins solely on the basis of liver enzyme abnormalities.

Sigh syndrome: is it a sign of trouble?

OBJECTIVE: The goal of this study was to identify the characteristics and clinical course of patients presenting with considerable stress regarding irrepressible persistent sighing, and to determine whether any association exists between this syndrome and respiratory or other organic disease, during the acute or follow-up period. STUDY DESIGN: We conducted a case series review of patients diagnosed with a defined symptom complex and gathered relevant data. POPULATION: Forty patients who presented to 3 family practice clinics in Israel met our 10 criteria for sigh syndrome: recurrent sighing; shallow respiration; conviction that deep breaths are obstructed; intensity of episodes provokes stress leading to consultation; no obvious trigger; episodes last a few days to several weeks; no interference with speech; sighing absent during sleep; no correlation with physical activity or rest; self-limited. OUTCOMES MEASURED: We assessed demographic and health status information, as well as recent circumstances that could have served as triggers for the symptoms. We also performed systematic diagnoses of acute or chronic organic disease. RESULTS: Physicians diagnosed "sigh syndrome" in 40 subjects (19 men [47.5%], 21 women [52.5%]), mean age 31.8 years, during the 3-year study period. All patients conformed to 10 sigh syndrome criteria. In 13 patients (32.5%), a significant traumatic event preceded onset of symptoms. Ten (25%) had previous anxiety or somatoform-related disorders. For 23 patients (57.5%), the episode repeated itself after the initial event. We found no association in any of the cases with any form of organic disease. Likewise, during the follow-up period (on average, 18 months), we did not observe the development of a specific organic disorder in any case. CONCLUSIONS: The "sigh syndrome" runs a benign course; it mainly demands the support and understanding of the treating physician to allay any patient concerns.

Preventive adolescent health care in family practice: a program summary.

The AMA Guidelines for Adolescent Preventive Services (GAPS) has been the cornerstone of preventive care for teenagers since its publication in 1994. Despite this, there has been little documentation of their implementation in the family medicine literature. This article gives an overview of a family practice-based adolescent preventive health program based on GAPS recommendations, and reports on compliance, feasibility and health issues. A Community-Oriented Primary Care (COPC) program targeted all adolescent patients aged 12-18 years in two Israeli family practices. 321 teenagers were invited to participate. Every 7th and 10th grader was invited for a preventive health visit with the family physician and nurse. The visits included a medical evaluation, screening and counseling regarding health issues recommended by GAPS, and counseling regarding personal health concerns. Parents were also invited to meet with the staff. 184 (57%) of the adolescents invited for health visits attended. The overall visit time was 47 minutes, including 12 minutes for a questionnaire and 35 minutes with providers. Common biomedical problems included overweight, acne and dysmenorrhea. Health risk behaviors and psychosocial problems included cigarette or alcohol use, dieting, infrequent/never seat belt use, and feeling depressed. 78% wanted to discuss at least one personal health issue. 27% were invited for follow-up visits. Only 3% of the parents came for visits. A community-oriented approach facilitates bringing adolescents for preventive health visits. Many previously undetected health issues, particularly psychosocial and behavioral, are revealed during these visits. A concerns checklist aids in addressing personal health concerns.