Decomposing the Response Time in Amblyopia: A Drift Diffusion Model Analysis.

Purpose: Amblyopes are known to have delayed response times (RT) in various visual tasks. We aim to investigate whether any factor other than the sensory deficit contributes to the delayed RT in amblyopia. Method: Fifteen amblyopic (26.0 ± 4.50 years) and 15 normal (25.6 ± 2.90 years) participants took part in this study. The responses and RTs in an orientation identification task were collected for each participant with stimulus contrast adjusted to the multiples of individual's threshold. A drift diffusion model was used to fit to the response and RT data and to estimate the RT components. Result: There was a significant difference in the RT between the amblyopic and normal groups (F(1, 28) = 6.75, P = 0.015) but no difference in the accuracy (F(1, 28) = 0.028, P = 0.868). The drift rate function in the amblyopic eye had a larger threshold (P = 0.001) and shallower slope (P = 0.006) than that of the fellow eye. The amblyopic group has a longer non-decision time than the normal group (F(1, 28) = 8.02, P = 0.008). The drift rate threshold correlated with the contrast sensitivity (P = 1.71 × 10-18) but the non-decision time did not (P = 0.393). Conclusions: Both sensory and post-sensory factors contributed to the delayed RT in amblyopia. The effect of the sensory loss in V1 on RT can be compensated by increasing stimulus contrast, and the post-sensory delay provides evidence for higher-level deficits in amblyopia.

Development and validation of a predictive model for patients with post-extubation dysphagia.

BACKGROUND: Swallowing disorder is a common clinical symptom that can lead to a series of complications, including aspiration, aspiration pneumonia, and malnutrition. This study aimed to investigate risk factors of post-extubation dysphagia (PED) in intensive care unit (ICU) patients with endotracheal intubation, and to develop a risk-predictive model for PED, which could serve as an assessment tool for the prevention and control of PED. METHODS: Patients retrospectively selected from June to December 2021 in a tertiary hospital served as the derivation cohort. Patients recruited from the same hospital from March to June 2022 served as the external validation cohort for the predictive model. We used a combination of variable screening and least absolute shrinkage and selection operator (LASSO) regression to select the most useful candidate predictors and checked the multicollinearity of independent variables using the variance inflation factor method. Multivariate logistic regression analysis was performed to calculate the odds ratio (OR; 95% confidence interval [95% CI]) and P-value for each variable to predict diagnosis. The screened risk factors were introduced into R software to build a nomogram model. The performance of the model, including discrimination ability, calibration, and clinical benefit, was evaluated by plotting the receiver operating characteristic (ROC), calibration, and decision curves. RESULTS: A total of 305 patients were included in this study. Among them, 235 patients (53 PED vs. 182 non-PED) were enrolled in the derivation cohort, while 70 patients (17 PED vs. 53 non-PED) were enrolled in the validation cohort. The independent predictors included age, pause of sedatives, level of consciousness, activities of daily living (ADL) score, nasogastric tube, sore throat, and voice disorder. These predictors were used to establish the predictive nomogram model. The model demonstrated good discriminative ability, and the area under the ROC curve (AUC) was 0.945 (95% CI 0.904-0.970). Applying the predictive model to the validation cohort demonstrated good discrimination with an AUC of 0.907 (95% CI 0.831-0.983) and good calibration. The decision-curve analysis of this nomogram showed a net benefit of the model. CONCLUSION: A predictive model that incorporates age, pause of sedatives, level of consciousness, ADL score, nasogastric tube, sore throat, and voice disorder may have the potential to predict PED in ICU patients.

Contrast Sensitivity Is Associated With Chorioretinal Thickness and Vascular Density of Eyes in Simple Early-Stage High Myopia.

Objective: To evaluate the contrast sensitivity function (CSF), chorioretinal thickness and vascular density as well as their relationships in subjects with simple early-stage high myopia. Methods: Eighty-one young subjects were enrolled in this study. They were categorized into the simple high myopia group (sHM, n = 51) and the low-moderate myopia group (control group, n = 30). Monocular CSF under best correction was measured with the qCSF method. Retinal superficial and deep vascular density, inner and outer retinal thickness and choroidal thickness were measured using optical coherence tomography angiography. Results: The area under log CSF (AULCSF) and cutoff spatial frequency (Cutoff SF) of the sHM group were significantly reduced compared to those of the control group (P = 0.003 and P < 0.001, respectively). The parafoveal and perifoveal retinal thickness, deep vascular density and choroidal thickness were also significantly reduced in the sHM group (all P < 0.05). Multiple regression analysis revealed that AULCSF was significantly correlated with retinal deep vascular density, outer retinal thickness in the parafoveal and perifoveal areas (all P < 0.05). Conclusion: Compared to low to moderate myopic eyes, patients with simple high myopia have thinner retinal and choroidal thickness, lower retinal vascular density, and reduced contrast sensitivity. Moreover, the CSF was correlated with the measures of chorioretinal structure and vasculature. The results suggest that the CSF is a sensitive functional endpoint in simple early-stage high myopia.

Defective Temporal Window of the Foveal Visual Processing in High Myopia.

Purpose: To investigate the temporal characteristics of visual processing at the fovea and the periphery in high myopia. Methods: Eighteen low (LM, ≤ -0.50 and > -6.00 D) and 18 high myopic (HM, ≤ -6.00 D) participants took part in this study. The contrast thresholds in an orientation discrimination task under various stimulus onset asynchrony (SOA) masking conditions were measured at the fovea and a more peripheral area (7°) for the two groups. An elaborated perceptual template model (ePTM) was fit to the behavioral data for each participant. Results: An analysis of variance with three factors (SOA, degree of myopia and eccentricity) was performed on the threshold data. The interaction between SOA and degree of myopia in the fovea was significant (F (4, 128) = 2.66, P = 0.036), suggesting that the masking effect had different temporal patterns between the two groups. The temporal profiles for the two groups were derived based on the ePTM model. The peak and the spread of the temporal window in the fovea were much lower and wider, respectively, in the HM group than that in the LM group (both Ps < 0.05). There was no significant difference in the peripheral temporal window between the two groups. Conclusions: High myopia is associated with defective temporal processing in the fovea, captured by a flattened temporal window.

Temporal Characteristics of Visual Processing in Amblyopia.

PURPOSE: Amblyopia affects not only spatial vision but also temporal vision. In this study, we aim to investigate temporal processing deficits in amblyopia. METHODS: Twenty amblyopic patients (age: 27.0 ± 5.53 years, 15 males), and 25 normal observers (age: 25.6 ± 4.03 years, 15 males) were recruited in this study. Contrast thresholds in an orientation discrimination task in five target-mask stimulus onset asynchronies (SOA) conditions (16.7 ms, 33.4 ms, 50.0 ms, 83.4 ms, and ∞/no noise) were measured. An elaborated perceptual template model (ePTM) was fit to the behavioral data to derive the temporal profile of visual processing for each participant. RESULTS: There were significant threshold differences between the amblyopic and normal eyes [F(1,43) = 10.6, p = 0.002] and a significant group × SOA interaction [F(2.75,118) = 4.98, p = 0.004], suggesting different temporal processing between the two groups. The ePTM fitted the data well (χ 2 test, all ps > 0.50). Compared to the normal eye, the amblyopic eye had a lower template gain (p = 0.046), and a temporal window with lower peak and broader width (all ps < 0.05). No significant correlation was found between the observed temporal deficits and visual acuity in amblyopia (ps > 0.50). Similar results were found in the anisometropic amblyopia subgroup. No significant difference was found between the fellow eyes of the monocular amblyopia and the normal eyes. CONCLUSION: Amblyopia is less efficient in processing dynamic visual stimuli. The temporal deficits in amblyopia, represented by a flattened temporal window, are likely independent of spatial vision deficits.