Optokinetic nystagmus as an assessment of visual attention to divided stimuli (2023)

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Eleven subjects were tested. There were nine male and two female subjects aged from 23–69 years. All subjects had unaided visual acuity of 0.75/5.0 (Snellen) or better. The test was performed with Snellen optotypes placed at a distance of 0.75 m from the subject’s eyes. The distance of the optokinetic curtain from the plane of the spectacle frames holding the infrared sensors of the eye tracker was 75 cm. All subjects had normal colour perception (Ishihara test) and full visual fields to


For the first and third tasks, a continuous, blink-free, 10 sec segment was selected for analysis. This was a minimum of 5 sec after the start and 5 sec before the finish of the task to attempt achieving as close an estimate of steady state as possible. For the second task (fixation and T search), the process of identifying the target itself may have influenced the eye movements, so measurements were made of two 4 sec portions of the trace, each finishing at least 1 sec before the subject


Examples of the sort of eye movements that were recorded during the three tasks are shown in Fig. 2. Plots of gain, amplitude and frequency for the three tasks are found in Fig. 3a,b,c. Means across tasks were found to be significantly different for gain (F=140.8, df=2, p<0.0001), amplitude (F=49.67, df=2, p<0.0001) and frequency (F=48.9, df=2, p<0.0001). All pair-wise comparisons for all tasks were significantly different at p<0.01 or better, except for the difference in amplitude between the


In this study, active fixation suppressed the passive reflexive response to a full field optokinetic stimulus. This ability was intact even in our oldest subjects. When a subject was asked to fixate the central target and simultaneously to pay covert attention to a feature of the full field optokinetic stimulus (task 2), top-down attention now had to be distributed between the fixation target and the moving background. Although suppression of OKN remained the objective, this became more


This study was supported by a grant from the Sunshine Foundation.

  • Effects of age and visual attention demands on optokinetic nystagmus suppression

    2019, Experimental Eye Research

    Citation Excerpt :

    Unfortunately, the ability to vary parameters is very limited for this test. More contemporarily, researchers have used OKN suppression as a means of evaluating the ability to spatially divide attention (Williams et al., 2006). The appeal of using OKN suppression is that one can vary the attentional task without changing the measure by which it is assessed.

    The utility of optokinetic nystagmus suppression as an index of visual attention has been demonstrated; however, a gap exists in our understanding of the effects of aging on attentional division. The purpose of this study was to explore the effect of a subject's age upon their ability to allocate visual attention among multiple salient elements which varied in location and complexity.

    Large-field optokinetic nystagmus (OKN)-inducing animations were presented along with a central flashing fixation point to 27 subjects: 15 younger adults (range 19–23, mean age 21.4); and 12 older adults (range 65–89, mean age 74). Subjects were instructed to fixate on a central point while attending to either moving features of the background or solely to the fixation target. Failure of subjects to accurately divide their attention was quantified by optokinetic gain (eye velocity/background velocity). Gain was analysed in two separate 3-way ANOVAs: one at the central location with the between-subjects variable of age and within-subjects variables of complexity and dynamism; and one using only the dynamic tasks, including a between-subjects variable of age and within-subjects variables of complexity and location.

    A strong effect of age was found between subjects during the more attentionally demanding dynamic tasks, but there was only a marginal effect during the static tasks. All within-subjects variables were highly significant, and there were several significant 2- and 3-way interactions.

    This study provides strong evidence for the compounding effects of senescence and stimulus characteristics on an adult's ability to accurately allocate visual attention. These findings show that OKN suppression may be a useful framework for quantification of attentional resources in older subjects.

  • Divided visual attention: A comparison of patients with multiple sclerosis and controls, assessed with an optokinetic nystagmus suppression task

    2016, Journal of Clinical Neuroscience

    Citation Excerpt :

    Suppression relies on the conscious effort of the subject. In previous studies we examined the degree to which such suppression can be maintained when other visual tasks are added [14,15]. We quantified the effect by measuring OKN gain, the ratio of eye velocity to stimulus velocity.

    Multiple sclerosis (MS) frequently causes impairment of cognitive function. We compared patients with MS with controls on divided visual attention tasks. The MS patients’ and controls’ stare optokinetic nystagmus (OKN) was recorded in response to a 24°/s full field stimulus. Suppression of the OKN response, judged by the gain, was measured during tasks dividing visual attention between the fixation target and a second stimulus, central or peripheral, static or dynamic. All participants completed the Audio Recorded Cognitive Screen. MS patients had lower gain on the baseline stare OKN. OKN suppression in divided attention tasks was the same in MS patients as in controls but in both groups was better maintained in static than in dynamic tasks. In only dynamic tasks, older age was associated with less effective OKN suppression. MS patients had lower scores on a timed attention task and on memory. There was no significant correlation between attention or memory and eye movement parameters. Attention, a complex multifaceted construct, has different neural combinations for each task. Despite impairments on some measures of attention, MS patients completed the divided visual attention tasks normally.

  • Attention in Drosophila

    2011, International Review of Neurobiology

    As bluntly summarized by a psychologist over a century ago, everyone knows what attention is [James (1890). The Principles of Psychology]. Attention describes our capacity to focus perception on one or a group of related stimuli while filtering out irrelevant stimuli. The ease we have in recognizing this astounding capacity in ourselves is matched by a surprising difficulty in identifying it in others, and this is especially the case for measuring attention in other animals. Identifying and measuring attention-like processes in simple animals such as flies requires, to some extent, even more rigor than asking the same question for our closer animal relatives, such as apes and monkeys. This is because flies have completely different brains than humans do, so to study attention in these creatures one must rely purely on operational or behavioral measures rather than comparative neuroanatomy. There is a long history of using sophisticated behavioral paradigms to study visual responses in Drosophila melanogaster, and these studies have often provided early evidence of attention-like processes in flies. More recently, these fly paradigms have been applied to measuring visual attention directly, and the combination of electrophysiology with these preparations has provided insight into how a fly might pay attention. Together with more efficient methods for measuring some aspects of attention, such as stimulus suppression, these approaches should begin to uncover how visual attention might work in a small brain.

  • Elements of exogenous attentional cueing preserved during optokinetic motion of the visual scene

    2022, European Journal of Neuroscience

  • Alertness and visual attention impact different aspects of the optokinetic reflex

    2021, Investigative Ophthalmology and Visual Science

  • Right frontal eye field has perceptual and oculomotor functions during optokinetic stimulation and nystagmus

    2020, Journal of Neurophysiology

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    Experimental Neurology, Volume 261, 2014, pp. 543-550

    Patients with small, non-debilitating strokes often report a reduction in quality of life due to persistent cognitive and emotional alterations. Stroke may directly damage limbic circuitry resulting in an impaired stress response, however the possibility that this may in part explain the prevalence of stroke comorbidity with mood disorders has yet to be determined. Here we systematically examine psychosocial consequences of prefrontal lesions targeting the left anterior cingulate cortex (ACC) using hormone assays and a behavioral test battery in adult rats to probe whether a small stroke could alter stress behavior or response to psychosocial stress (chronic mild stress (CMS) or subordination stress).

    Minor stroke produced chronic hyperactivity in an open field but did not alter fear-related inhibition in the elevated plus maze. Novelty-induced defecation was increased by the combination of CMS, subordination and stroke. Anterior cingulate lesions alone increased distress vocalizations in the water maze. Interestingly, ACC stroke caused hyper-secretion of porphyrin and long-term hormonal alterations that resulted in adrenal hypertrophy and enhanced dexamethasone suppression of the HPA axis. We propose that this behavioral profile is consistent with an animal model of post-stroke distress-like syndrome which could be useful in understanding how stroke affects the capacity to cope with psychological stress.

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    The Design and Assessment of a Multiparametric Model for the Dysphonia Severity Index for Persian-speaking Populations

    Journal of Voice, Volume 33, Issue 2, 2019, pp. 226-231

    In instrumental voice assessment, multiparametric models reflect the multidimensional nature of voice and are therefore better than models that reflect only a single dimension of voice. The Dysphonia Severity Index (DSI) is one of the most common multiparametric models. In voice assessment, race, language, and structural and physiological features affect the acoustic, aerodynamic, and voice range profile measures. Given these differences, this study was conducted to design and evaluate a multiparametric and objective model for assessing the severity of dysphonia in Persian-speaking populations.

    This study examined 300 participants with several types of dysphonia (104 women and 196 men) and 100 healthy individuals (63 women and 37 men). Five acoustic parameters, three aerodynamic parameters, and seven voice range profile parameters were measured for designing the model. Perceptual evaluation was performed using the grade, roughness, breathiness, asthenia, strain scale. The logistic regression analysis was used to determine the factors affecting the DSI and each component's coefficient.

    Of the 15 parameters assessed, shimmer, vital capacity, semitone range, and voice onset time of /pa/ remained in the model with their coefficients. This section presents the DSI model for the examined population. The discriminant analysis showed that this combination corresponds to 47.8 of the perceptual assessment: DSI = 0.289 (shimmer) + 0.0001 (VC) − 0.059 (STR) − 13.278 (VOT_Pa).

    In this study, the DSI corresponded to the physiological, linguistic, and racial characteristics of the Persian-speaking population with or without voice disorder.

  • Research article

    Using Rate of Divergence as an Objective Measure to Differentiate between Voice Signal Types Based on the Amount of Disorder in the Signal

    Journal of Voice, Volume 31, Issue 1, 2017, pp. 16-23

    The purpose of this paper is to introduce the rate of divergence as an objective measure to differentiate between the four voice types based on the amount of disorder present in a signal. We hypothesized that rate of divergence would provide an objective measure that can quantify all four voice types.

    A total of 150 acoustic voice recordings were randomly selected and analyzed using traditional perturbation, nonlinear, and rate of divergence analysis methods.

    We developed a new parameter, rate of divergence, which uses a modified version of Wolf's algorithm for calculating Lyapunov exponents of a system. The outcome of this calculation is not a Lyapunov exponent, but rather a description of the divergence of two nearby data points for the next three points in the time series, followed in three time-delayed embedding dimensions. This measure was compared to currently existing perturbation and nonlinear dynamic methods of distinguishing between voice signals.

    There was a direct relationship between voice type and rate of divergence. This calculation is especially effective at differentiating between type 3 and type 4 voices (P < 0.001) and is equally effective at differentiating type 1, type 2, and type 3 signals as currently existing methods.

    The rate of divergence calculation introduced is an objective measure that can be used to distinguish between all four voice types based on the amount of disorder present, leading to quicker and more accurate voice typing as well as an improved understanding of the nonlinear dynamics involved in phonation.

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    Is intraoperative neural monitoring necessary for exploration of the superior laryngeal nerve?

    Surgery, Volume 161, Issue 4, 2017, pp. 1129-1138

    We aimed to evaluate the contribution of intraoperative neuromonitoring to the visual and functional identification of the external branch of the superior laryngeal nerve and the effect on postoperative voice changes.

    The prospective data of 221 patients (183 women, 38 men) who underwent thyroid operation with intraoperative neuromonitoring for exploration of the external branch of the superior laryngeal nerve were evaluated retrospectively. The surface endotracheal tube–based Medtronic NIM3 (Medtronic, Jacksonville, FL) intraoperative neuromonitoring device was used. The function of the external branch of the superior laryngeal nerve was evaluated by cricothyroid muscle twitch. Additionally, the contribution of the external branch of the superior laryngeal nerve to vocal cord adduction was evaluated using electromyographic records.

    A total of 374 (95.2%) of 393 external branch of the superior laryngeal nerves were identified; 145 (36.9%) external branch of the superior laryngeal nerves were identified visually before being stimulated with a probe, and 130 (33.1%) external branch of the superior laryngeal nerves were identified visually after being identified with a probe. Although 99 (25.2%) external branch of the superior laryngeal nerves were identified with a probe, they were not visualized. Intraoperative neuromonitoring provided meaningful contributions to visual (P = .001) and functional (P = .001) identification of the external branch of the superior laryngeal nerve. Positive electromyographic responses were recorded from 257 external branch of the superior laryngeal nerves (68.7%). After the patients with recurrent laryngeal nerve palsy were excluded, voice changes were detected in 6 (3.3%) of 184 patients with identified external branch of the superior laryngeal nerves and 3 (20%) of 15 patients in whom at least 1 external branch of the superior laryngeal nerve could not be identified with intraoperative neuromonitoring.

    Intraoperative neuromonitoring provided an important contribution to the visual and functional identification of the external branch of the superior laryngeal nerve. Intraoperative neuromonitoring is a helpful adjunct for identifying the external branch of the superior laryngeal nerve.

  • Research article

    Electrocardiographic measurement of infarct size compared to cardiac MRI in reperfused first time ST-segment elevation myocardial infarction

    International Journal of Cardiology, Volume 220, 2016, pp. 389-394

    Myocardial infarct size (IS) following ST-segment elevation myocardial infarction (STEMI) is an important prognostic factor. We assessed the Selvester 32-point QRS score from the 12-lead ECG for measurement of IS in STEMI patients receiving reperfusion therapy compared to cardiac magnetic resonance imaging (CMRI). Furthermore we sought to explore the impact of microvascular obstruction (MVO) on the scoring system, and determine factors contributing to discrepancies between CMRI IS and Selvester score.

    We examined 70 patients (55 men, 15 women), mean age 57±10years with a first time STEMI (46 anterior, 24 non-anterior). QRS scores were calculated early and at follow-up (mean 2±1 and 59±14days post-STEMI). Myocardial core scar size (5SD) was measured at 5.3±3.3 and 57.8±13.5days post-infarction by CMRI. MVO was determined on initial MRI. Logistic regression analysis was performed to determine factors contributing to discordant scores, defined as a difference between CMRI and Selvester IS of >6% myocardium.

    QRS scoring of anterior infarcts correlated with CMRI IS both early (r=0.734, p<0.0001) and at follow-up (r=0.716, p<0.0001); however no correlation was seen among non-anterior infarcts. QRS scoring overestimated IS at all time points. There was better agreement between ECG and CMRI measured IS in patients without MVO at both time points. Anterior infarction was inversely predictive of discordant IS estimation acutely, and larger Selvester scores were predictive of inaccurate scoring at both time periods.

    Selvester QRS score correlates well with CMRI IS for anterior infarcts. MVO did not independently affect the score.

  • Research article

    Top-Down Mechanisms in Dysphonia Perception: The Need for Blind Tests

    Journal of Voice, Volume 27, Issue 4, 2013, pp. 481-485

    The purpose of this study was to determine the extent to which the information a therapist or a physician has about a dysphonic speaker, particularly whether he or she is in the pretreatment or posttreatment period, can influence judgments of the patient's voice. The voices of 53 dysphonic speakers were used in the study. For each speaker, we selected a pair of voice samples recorded under different circumstances. Seven listeners who were speech therapists, ear, nose, and throat surgeons, or voice pathologists took blind-listening tests in which they were asked to compare the two voices in each pair (phase 1: blind listening). A few weeks later, the listeners took the very same test again, except that this time, they were given bogus information about whether the speaker had/had not been treated by laryngeal surgery or speech therapy (phase 2: influenced listening). The information given for each voice sample either reinforced the judgment made in phase 1 (eg, the voice judged to be better on the blind test was said to be posttreatment) or countered thatjudgment (eg, the voice rated as better on the blind test was said to be pretreatment). The influenced-listening results showed that in the reinforced condition, the original ratings were significantly amplified. By contrast, in the countering-influence condition, decision changes were frequent: we found that judgment reversals and the countering-information scores were almost independent of the blind-listening scores. These findings point out the dire need to use a blind protocol in perceptual assessments of dysphonia.

Copyright © 2006 Elsevier Ltd. All rights reserved.


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