Enhancing Performance of SSVEP-Based Visual Acuity via Spatial Filtering

The purpose of this study was to enhance the performance of steady-state visual evoked potential (SSVEP)-based visual acuity assessment with spatial filtering methods. Using the vertical sinusoidal gratings at six spatial frequency steps as the visual stimuli for 11 subjects, SSVEPs were recorded from six occipital electrodes (O1, Oz, O2, PO3, POz, and PO4). Ten commonly used training-free spatial filtering methods, i.e., native combination (single-electrode), bipolar combination, Laplacian combination, average combination, common average reference (CAR), minimum energy combination (MEC), maximum contrast combination (MCC), canonical correlation analysis (CCA), multivariate synchronization index (MSI), and partial least squares (PLS), were compared for multielectrode signals combination in SSVEP visual acuity assessment by statistical analyses, e.g., Bland–Altman analysis and repeated-measures ANOVA. The SSVEP signal characteristics corresponding to each spatial filtering method were compared, determining the chosen spatial filtering methods of CCA and MSI with a higher performance than the native combination for further signal processing. After the visual acuity threshold estimation criterion, the agreement between the subjective Freiburg Visual Acuity and Contrast Test (FrACT) and SSVEP visual acuity for the native combination (0.253 logMAR), CCA (0.202 logMAR), and MSI (0.208 logMAR) was all good, and the difference between FrACT and SSVEP visual acuity was also all acceptable for the native combination (−0.095 logMAR), CCA (0.039 logMAR), and MSI (−0.080 logMAR), where CCA-based SSVEP visual acuity had the best performance and the native combination had the worst. The study proved that the performance of SSVEP-based visual acuity can be enhanced by spatial filtering methods of CCA and MSI and also recommended CCA as the spatial filtering method for multielectrode signals combination in SSVEP visual acuity assessment.

Download Full-text

Does Oblique Effect Affect SSVEP-Based Visual Acuity Assessment?

Frontiers in Neuroscience ◽

10.3389/fnins.2021.784888 ◽

2022 ◽

Vol 15 ◽

Author(s):

Xiaowei Zheng ◽

Guanghua Xu ◽

Yuhui Du ◽

Hui Li ◽

Chengcheng Han ◽

...

Keyword(s):

Visual Acuity ◽

Signal To Noise Ratio ◽

Visual Stimuli ◽

Oblique Effect ◽

Stimulus Orientation ◽

Threshold Estimation ◽

Signal Characteristics ◽

Significant Difference ◽

Sinusoidal Gratings ◽

Reversal Frequency

This study aimed to explore whether there was an effect on steady-state visual evoked potential (SSVEP) visual acuity assessment from the oblique effect or the stimulus orientation. SSVEPs were induced by seven visual stimuli, e.g., the reversal sinusoidal gratings with horizontal, two oblique, and vertical orientations, reversal checkerboards with vertical and oblique orientations, and oscillating expansion-contraction concentric-rings, at six spatial frequency steps. Ten subjects participated in the experiment. Subsequently, a threshold estimation criterion was used to determine the objective SSVEP visual acuity corresponding to each visual stimulus. Taking the SSVEP amplitude and signal-to-noise-ratio (SNR) of the fundamental reversal frequency as signal characteristics, both the SSVEP amplitude and SNR induced by the reversal sinusoidal gratings at 3.0 cpd among four stimulus orientations had no significant difference, and the same finding was also shown in the checkerboards between vertical and oblique orientation. In addition, the SSVEP visual acuity obtained by the threshold estimation criterion for all seven visual stimuli showed no significant difference. This study demonstrated that the SSVEPs induced by all these seven visual stimuli had a similarly good performance in evaluating visual acuity, and the oblique effect or the stimulus orientation had little effect on SSVEP response as well as the SSVEP visual acuity.

Download Full-text

Force Generation on the Hallux Is More Affected by the Ankle Joint Angle than the Lesser Toes: An In Vivo Human Study

Biology ◽

10.3390/biology10010048 ◽

2021 ◽

Vol 10 (1) ◽

pp. 48

Author(s):

Junya Saeki ◽

Soichiro Iwanuma ◽

Suguru Torii

Keyword(s):

Repeated Measures ◽

Joint Angle ◽

Plantar Flexion ◽

Human Study ◽

Force Generation ◽

Functional Difference ◽

Multiple Comparison Test ◽

The Difference ◽

Metatarsophalangeal Joints

The structure of the first toe is independent of that of the other toes, while the functional difference remains unclear. The purpose of this study was to investigate the difference in the force generation characteristics between the plantar-flexion of the first and second–fifth metatarsophalangeal joints (MTPJs) by comparing the maximal voluntary plantar-flexion torques (MVC torque) at different MTPJs and ankle positions. The MVC torques of the first and second–fifth MTPJs were measured at 0°, 15°, 30°, and 45° dorsiflexed positions of the MTPJs, and at 20° plantar-flexed, neutral, and 20° dorsiflexed positions of the ankle. Two-way repeated measures analyses of variance with Holm’s multiple comparison test (MTPJ position × ankle position) were performed. When the MTPJ was dorsiflexed at 0°, 15°, and 30°, the MVC torque of the first MTPJ when the ankle was dorsiflexed at 20° was higher than that when the ankle was plantar-flexed at 20°. However, the ankle position had no significant effect on the MVC torque of the second–fifth MTPJ. Thus, the MVC torque of the first MTPJ was more affected by the ankle position than the second–fifth MTPJs.

Download Full-text

Estimating and reporting treatment effects in clinical trials for weight management: using estimands to interpret effects of intercurrent events and missing data

International Journal of Obesity ◽

10.1038/s41366-020-00733-x ◽

2021 ◽

Cited By ~ 1

Author(s):

Sean Wharton ◽

Arne Astrup ◽

Lars Endahl ◽

Michael E. J. Lean ◽

Altynai Satylganova ◽

...

Keyword(s):

Clinical Trials ◽

Missing Data ◽

Weight Management ◽

Treatment Effect ◽

Repeated Measures ◽

Treatment Effects ◽

Randomized Clinical Trials ◽

Weight Losses ◽

The Difference ◽

Treatment Of Obesity

AbstractIn the approval process for new weight management therapies, regulators typically require estimates of effect size. Usually, as with other drug evaluations, the placebo-adjusted treatment effect (i.e., the difference between weight losses with pharmacotherapy and placebo, when given as an adjunct to lifestyle intervention) is provided from data in randomized clinical trials (RCTs). At first glance, this may seem appropriate and straightforward. However, weight loss is not a simple direct drug effect, but is also mediated by other factors such as changes in diet and physical activity. Interpreting observed differences between treatment arms in weight management RCTs can be challenging; intercurrent events that occur after treatment initiation may affect the interpretation of results at the end of treatment. Utilizing estimands helps to address these uncertainties and improve transparency in clinical trial reporting by better matching the treatment-effect estimates to the scientific and/or clinical questions of interest. Estimands aim to provide an indication of trial outcomes that might be expected in the same patients under different conditions. This article reviews how intercurrent events during weight management trials can influence placebo-adjusted treatment effects, depending on how they are accounted for and how missing data are handled. The most appropriate method for statistical analysis is also discussed, including assessment of the last observation carried forward approach, and more recent methods, such as multiple imputation and mixed models for repeated measures. The use of each of these approaches, and that of estimands, is discussed in the context of the SCALE phase 3a and 3b RCTs evaluating the effect of liraglutide 3.0 mg for the treatment of obesity.

Download Full-text

Comparison of the Effectiveness of Intravitreal Ranibizumab for Diabetic Macular Edema in Vitrectomized and Nonvitrectomized Eyes

Ophthalmologica ◽

10.1159/000446992 ◽

2016 ◽

Vol 236 (2) ◽

pp. 67-73 ◽

Cited By ~ 5

Author(s):

Yoshito Koyanagi ◽

Shigeo Yoshida ◽

Yoshiyuki Kobayashi ◽

Yuki Kubo ◽

Muneo Yamaguchi ◽

...

Keyword(s):

Visual Acuity ◽

Macular Edema ◽

Diabetic Macular Edema ◽

Treatment Option ◽

Central Macular Thickness ◽

Intravitreal Ranibizumab ◽

Corrected Visual Acuity ◽

The Mean ◽

The Difference ◽

Best Corrected Visual Acuity

Purpose: To compare the effectiveness of intravitreal ranibizumab (IVR) for diabetic macular edema (DME) between eyes with and without previous vitrectomy. Procedures: We prospectively assessed the best-corrected visual acuity (BCVA) and central macular thickness (CMT) after IVR for 6 months. Results: There were no significant differences in the baseline BCVA and CMT between both groups. In the nonvitrectomized group (n = 15), the mean changes of BCVA and CMT from baseline to month 6 were significant (p < 0.01). In the vitrectomized group (n = 10), the improvement appeared to be slower, and the mean BCVA improvement was not significant (p = 0.5), although the mean CMT decrease was significant (p < 0.05). There were no significant differences in the mean changes of BCVA and CMT between both groups at 6 months. Conclusions: The difference in the effectiveness of IVR between both groups was not significant. IVR can be a treatment option even for vitrectomized DME eyes.

Download Full-text

Outcomes of Femtosecond Laser Assisted Cataract Surgery Performed by Resident and Attending Surgeons

Journal of Academic Ophthalmology ◽

10.1055/s-0041-1725582 ◽

2021 ◽

Vol 13 (01) ◽

pp. e26-e31

Author(s):

Spencer C. Cleland ◽

Daniel W. Knoch ◽

Jennifer C. Larson

Keyword(s):

Visual Acuity ◽

Femtosecond Laser ◽

Cataract Surgery ◽

Retrospective Chart Review ◽

Dissipated Energy ◽

Independent Practice ◽

Postoperative Visual Acuity ◽

Included Patient ◽

Duration Of Surgery ◽

The Difference

Abstract Objective The study aimed to evaluate the safety and efficacy of resident surgeons performing femtosecond laser assisted cataract surgery (FLACS). Methods A retrospective chart review was conducted at the University of Wisconsin-Madison from postgraduate year four residents performing FLACS between 2017 and 2019. Data were also collected from residents performing manual cataract surgery, and attending surgeons performing FLACS for comparison. Recorded data included patient demographics, pre- and postoperative visual acuity, pre- and postoperative spherical equivalent, nuclear sclerotic cataract grade, ocular and systemic comorbidities, intraocular lens, duration of surgery, cumulative dissipated energy (CDE), and intraoperative and postoperative complications. Results A total of 90 cases were reviewed with 30 resident manual cases, 30 resident FLACS cases, and 30 attending FLACS cases. Resident manual (25.5 ± 6.8 minutes) and resident FLACS (17.5 ± 7.1 minutes) cases took a significantly longer time to complete compared with attending FLACS cases (13.6 ± 4.4 minutes; p < 0.001). There was higher CDE in resident FLACS and resident manual cases compared with attending FLACS cases, but the difference was not statistically significant (p = 0.06). Postoperative visual acuity was not statistically different at 1-day and 1-month after surgery among the three groups. Resident FLACS complications, which included one case requiring an intraoperative suture to close the wound, two cases with intraoperative corneal abrasions, two cases with postoperative ocular hypertension, and one case with cystoid macular edema, were not significantly greater than attending FLACS complications (p = 0.30). Conclusion The FLACS performed by resident surgeons had comparable visual acuity outcomes to FLACS performed by attending surgeons, and to manual cataract surgery performed by resident surgeons. However, resident FLACS cases took significantly longer time to complete, and they were associated with a higher CDE and minor complication rate compared with attending FLACS cases. Introducing advanced technologies into surgical training curricula improves resident preparedness for independent practice, and this study suggests FLACS can be incorporated safely and effectively into resident education.

Download Full-text

The Effect of Exercise on Respiratory Resistance in Athletes With and Without Paradoxical Vocal Fold Motion Disorder

American Journal of Speech-Language Pathology ◽

10.1044/2015_ajslp-14-0110 ◽

2015 ◽

Vol 24 (3) ◽

pp. 470-479 ◽

Cited By ~ 4

Author(s):

Sally J. K. Gallena ◽

Nancy Pearl Solomon ◽

Arthur T. Johnson ◽

Jafar Vossoughi ◽

Wei Tian

Keyword(s):

Repeated Measures ◽

Vocal Fold ◽

Female Athletes ◽

Exercise Duration ◽

Treadmill Running ◽

Respiratory Resistance ◽

The Difference ◽

Airflow Perturbation Device ◽

Vocal Fold Motion ◽

Paradoxical Vocal Fold Motion

Purpose An investigational, portable instrument was used to assess inspiratory (R i ) and expiratory (R e ) resistances during resting tidal breathing (RTB), postexercise breathing (PEB), and recovery breathing (RB) in athletes with and without paradoxical vocal fold motion disorder (PVFMD). Method Prospective, controlled, repeated measures within-subject and between-groups design. Twenty-four teenage female athletes, 12 with and 12 without PVFMD, breathed into the Airflow Perturbation Device for baseline measures of respiratory resistance and for two successive 1-min trials after treadmill running for up to 12 min. Exercise duration and dyspnea ratings were collected and compared across groups. Results Athletes with PVFMD had lower than control R i and R e values during RTB that significantly increased at PEB and decreased during RB. Control athletes' R e decreased significantly from RTB to PEB but not from PEB to RB, whereas R i did not change from RTB to PEB but decreased from PEB to RB. Athletes without PVFMD ran longer, providing lower dyspnea ratings. Conclusion Immediately following exercise, athletes with PVFMD experienced increased respiratory resistance that affected their exercise performance. The difference in resting respiratory resistances between groups is intriguing and could point to anatomical differences or neural adaptation in teenagers with PVFMD. The Airflow Perturbation Device appears to be a clinically feasible tool that can provide insight into PVFMD and objective data for tracking treatment progress.

Download Full-text

Attention Deficit Hyperactivity Disorder, Creativity, and the Effects of Methylphenidate

PEDIATRICS ◽

10.1542/peds.91.4.816 ◽

1993 ◽

Vol 91 (4) ◽

pp. 816-819

Author(s):

Jeanne B. Funk ◽

John B. Chessare ◽

Michael T. Weaver ◽

Anita R. Exley

Keyword(s):

Attention Deficit Hyperactivity Disorder ◽

Attention Deficit ◽

Repeated Measures ◽

Creative Thinking ◽

Adhd Group ◽

Hyperactivity Disorder ◽

Significant Difference ◽

Quasi Experimental ◽

The Difference ◽

Clinically Significant

Given that children with attention deficit hyperactivity disorder (ADHD) are more impulsive than peers, this study explored whether they are correspondingly more creative, and whether creativity declines when impulsivity is decreased through methylphenidate (Ritalin) therapy. A repeated-measures quasi-experimental design was used to compare the performance of 19 boys with previously diagnosed ADHD and 21 comparison boys aged 8 through 11 on two administrations of alternate forms of the Torrance Tests of Creative Thinking-Figural (nonverbal). Boys with ADHD received prescribed methylphenidate only for the first session. Overall, mean Torrance summary scores for comparison boys (mean = 115.1, SD = 16.1) were higher than for boys with ADHD (mean = 107.6, SD = 12.7). However, the difference between means was small (7%) and did not meet the 25% criterion for a clinically significant difference. No changes in performance over time (comparison group) or medication state (ADHD group) were observed. These data suggest that, when measured nonverbally, the creative thinking performance of boys with ADHD is not superior to that of peers who do not have ADHD. Regarding the effects of methylphenidate, prescribed therapy did not influence performance on this measure of creative thinking.

Download Full-text

Comparison of the Remineralizing Effect of Brushing with Aloe vera versus Fluoride Toothpaste

European Journal of Dentistry ◽

10.1055/s-0040-1716597 ◽

2020 ◽

Author(s):

Teresa Al Haddad ◽

Elie Khoury ◽

Nada Farhat Mchayleh

Keyword(s):

Repeated Measures ◽

Aloe Vera ◽

In Vitro Study ◽

P Value ◽

Fluoride Toothpaste ◽

Before And After ◽

The Difference ◽

Group B ◽

Ca:P Ratio

Abstract Objectives The aim of the present in vitro study is to compare the remineralization brushing effect of three toothpastes and Aloe vera (AV) gel. Materials and Methods Forty sound extracted teeth were placed in a demineralizing solution for 4 days and randomly assigned to four groups: group A: 1,450-ppm fluoride toothpaste; group B: AV nonfluoridated toothpaste; group C: AV 1,000-ppm fluoridated toothpaste; and group D: AV gel. A 3-minute pH cycling was performed twice a day for each group for 12 days. Specimens were analyzed before and after by scanning electron microscope—energy dispersive X-ray. Statistical analysis The outcomes were analyzed by Kolmogorov–Smirnov’s tests, repeated-measures analyses of variance followed by univariate analyses, and Bonferroni’s multiple comparisons tests to compare the calcium-to-phosphorus (Ca:P) ratio within time among toothpaste groups. Results Following remineralization, the Ca:P ratio increased in all groups. The difference of the Ca:P ratio was not significant between groups C, D, and A. The mean ratio was significantly lower in group B (p-value = 0.026). Conclusions The AV gel demonstrated a remineralization capacity equal to that of the 1,450-ppm fluoride toothpaste. In contrast, fluoride-free AV toothpaste showed a lower remineralization efficiency. Further studies are required to understand its mechanism.

Download Full-text