Category: Statistics

J Breath Res. 2022 Feb 4. doi: 10.1088/1752-7163/ac522f. Online ahead of print.

ABSTRACT

Cystic fibrosis (CF) is characterized by chronic respiratory infections which progressively decrease lung function over time. Affected individuals experience episodes of intensified respiratory symptoms called pulmonary exacerbations (PEx) which accelerate pulmonary function decline and decrease survival. There is no standard classification for PEx, which results in treatments that are heterogeneous. Improving PEx classification and management is a significant priority for people with CF. Previous studies have shown volatile organic compounds (VOCs) in exhaled breath can be used as biomarkers because they are products of metabolic pathways dysregulated by different diseases. To provide insights on PEx classification and other clinical factors, exhaled breath was collected from subjects with CF, with some experiencing PEx and others at baseline. Exhaled breath was collected in Tedlar bags during tidal breathing for VOC analysis by solid phase microextraction coupled to gas chromatography-mass spectrometry. Statistical significance testing between quantitative and categorical clinical variables displayed percent-predicted forced expiratory volume in one second (FEV1pp) was decreased in subjects experiencing PEx. VOCs correlating with other clinical variables (body mass index, age, use of highly effective modulator therapies, and need for antibiotics) were also explored. VOCs correlating to potential confounding variables were removed and analyzed by regression for correlations with FEV1pp measurements. The VOC with the highest correlation with FEV1pp (3,7-dimethyldecane) also gave the lowest p-value when comparing subjects at baseline and during PEx. Receiver operator characteristic curves showed 3,7-dimethyldecane had a higher ability to classify PEx (area under the curve (AUC) = 0.91) relative to FEV1pp values at collection (AUC = 0.83). However, normalized ΔFEV1pp values had the highest capability to distinguish PEx (AUC = 0.93). These results show that exhaled VOCs may be a source of biomarkers for various clinical traits of CF, including PEx, that should be explored in larger sample cohorts and validation studies.

PMID:35120338 | DOI:10.1088/1752-7163/ac522f

J Neurosurg. 2022 Feb 4:1-8. doi: 10.3171/2021.12.JNS212416. Online ahead of print.

ABSTRACT

OBJECTIVE: The object of this study was to evaluate the safety, efficacy, and long-term outcomes of stereotactic radiosurgery (SRS) in the management of intracranial chordomas.

METHODS: This retrospective multicenter study involved consecutive patients managed with single-session SRS for an intracranial chordoma at 10 participating centers. Radiological and neurological outcomes were assessed after SRS, and predictive factors were evaluated via statistical methodology.

RESULTS: A total of 93 patients (56 males [60.2%], mean age 44.8 years [SD 16.6]) underwent single-session SRS for intracranial chordoma. SRS was utilized as adjuvant treatment in 77 (82.8%) cases, at recurrence in 13 (14.0%) cases, and as primary treatment in 3 (3.2%) cases. The mean tumor volume was 8 cm3 (SD 7.3), and the mean prescription volume was 9.1 cm3 (SD 8.7). The mean margin and maximum radiosurgical doses utilized were 17 Gy (SD 3.6) and 34.2 Gy (SD 6.4), respectively. On multivariate analysis, treatment failure due to tumor progression (p = 0.001) was associated with an increased risk for post-SRS neurological deterioration, and a maximum dose > 29 Gy (p = 0.006) was associated with a decreased risk. A maximum dose > 29 Gy was also associated with improved local tumor control (p = 0.02), whereas the presence of neurological deficits prior to SRS (p = 0.04) and an age > 65 years at SRS (p = 0.03) were associated with worse local tumor control. The 5- and 10-year tumor progression-free survival rates were 54.7% and 34.7%, respectively. An age > 65 years at SRS (p = 0.01) was associated with decreased overall survival. The 5- and 10-year overall survival rates were 83% and 70%, respectively.

CONCLUSIONS: SRS appears to be a safe and relatively effective adjuvant management option for intracranial chordomas. The best outcomes were obtained in younger patients without significant neurological deficits. Further well-designed studies are necessary to define the best timing for the use of SRS in the multidisciplinary management of intracranial chordomas.

PMID:35120328 | DOI:10.3171/2021.12.JNS212416

Altern Ther Health Med. 2022 Jan;28(1):8-10.

ABSTRACT

CONTEXT: Rice Bran Arabinoxylan Compound (RBAC) is a trusted and proven immunomodulator made from a rice bran extract that has been enzymatically modified with an enzyme complex from the shiitake mushroom.

OBJECTIVE: The study’s primary objective was to identify the role of RBAC in supporting cancer therapies.

DESIGN: The author designed an open study.

PARTICIPANTS: Participants were 14 patients who are suffering from various type of malignancies.

INTERVENTION: BRM4 capsules-a commercially available, proprietary RBAC supplement-were administered.

OUTCOME MEASURES: The study measured circulating tumor cells (CTC) and tumor markers-the prostate-specific antigen (PSA) and cancer antigens 125 (CA125) 15-3 (CA15-3), and 27-29 (CA27-29) for the relevant malignancy.

RESULTS: Twelve out of 14 participants completed the protocol, and two participants died during the study. Of the 12 participants completing the study, the CTC levels were reduced in 10, with a statistically significant difference between the testing at baseline and postintervention (P = .0047). The tumor markers of various malignancies decreased for nine out the 12 participants, and one participant experienced remission.

CONCLUSIONS: The results suggest that the product can be an effective immunomodulator that can complement conventional cancer treatment.

PMID:35120333

J Neurosurg Spine. 2022 Feb 4:1-9. doi: 10.3171/2021.12.SPINE211090. Online ahead of print.

ABSTRACT

OBJECTIVE: Long posterior cervical decompression and fusion (PCF) is commonly performed to surgically treat patients with multilevel cervical pathology. In cases in which constructs may necessitate crossing the cervicothoracic junction (CTJ), recommendations for appropriate caudal fusion level vary in the literature. The aim of this study was to report the clinical and radiological outcomes of multilevel PCFs ending at C7 versus those crossing the CTJ.

METHODS: A systematic search of PubMed, CINAHL Plus, and Scopus was conducted to identify articles that evaluated clinical and radiological outcomes of long PCFs that ended at C7 (cervical group) or crossed the CTJ (thoracic group). Based on heterogeneity, random-effects models of a meta-analysis were used to estimate the pooled estimates and the 95% confidence intervals.

RESULTS: PCF outcome data of 1120 patients from 10 published studies were included. Compared with the cervical group, the thoracic group experienced greater mean blood loss (453.0 ml [95% CI 333.6-572.5 ml] vs 303.5 ml [95% CI 203.4-403.6 ml]), longer operative times (235.5 minutes [95% CI 187.7-283.3 minutes] vs 198.5 minutes [95% CI 157.9-239.0 minutes]), and a longer length of stay (6.7 days [95% CI 3.3-10.2 days] vs 6.2 days [95% CI 3.8-8.7 days]); however, these differences were not statistically significant. None of the included studies specifically investigated factors that led to the decision of whether to cross the CTJ. The cervical group had a mean fusion rate of 86% (95% CI 71%-94%) compared with the thoracic group with a rate of 90% (95% CI 81%-95%). Of patients in the cervical group, 17% (95% CI 10%-28%) required revision surgery compared with 7% (95% CI 4%-13%) of those in the thoracic group, but this difference was not statistically significant. The proportion of patients who experienced complications in the cervical group was found to be 28% (95% CI 12%-52%) versus 14% (95% CI 7%-26%) in the thoracic group; however, this difference was not statistically significant. There was no significant difference (no overlap of 95% CIs) in the incidence of adjacent-segment disease, pseudarthrosis, or wound-related complications between groups.

CONCLUSIONS: This meta-analysis suggests similar clinical and radiographic outcomes in multilevel PCF, regardless of inclusion of the CTJ. The lowest instrumented level did not significantly affect revision rates or complications. The ideal stopping point must be tailored to each patient on an individualized basis.

PMID:35120314 | DOI:10.3171/2021.12.SPINE211090

Psychol Res Behav Manag. 2022 Jan 25;15:183-192. doi: 10.2147/PRBM.S346658. eCollection 2022.

ABSTRACT

PURPOSE: Adolescent bullying has varying degrees of negative impact on both bullies and victims. Bullying in adolescents is complex, and the influence of individual factors and social factors should not be underestimated. Normative beliefs about aggression play an important role in adolescents’ bullying. However, the mediating and moderating mechanisms underlying this association remain largely unknown. The current study investigated the mediating role of moral disengagement between normative beliefs about aggression and bullying, as well as the moderating role of self-control in this relationship from the perspective of individual cognition.

METHODS: A sample of 491 Chinese adolescents (female = 38.9%; mean age = 13.05 years) were study participants. They completed questionnaires about normative beliefs about aggression, bullying, moral disengagement and self-control. SPSS21.0 statistical software was used to collate the obtained data, analyze descriptive statistics, and carry out reliability analysis and correlation analysis.

RESULTS: Moral disengagement mediated the relationship between normative beliefs about aggression and bullying (ab=0.13, 95% CI=[0.07, 0.21]). The association between normative beliefs about aggression and moral disengagement was moderated by self-control (β=-0.08, t=-2.25, p<0.05). The association between moral disengagement and bullying was moderated by self-control (β=-0.09, t=-2.42, p<0.05).

CONCLUSION: Results revealed that moral disengagement mediates the link between normative beliefs about aggression and bullying. Self-control moderated the relationship between normative beliefs about aggression and moral disengagement, and between moral disengagement and bullying.

PMID:35115850 | PMC:PMC8800860 | DOI:10.2147/PRBM.S346658

J Vis. 2022 Feb 1;22(3):7. doi: 10.1167/jov.22.3.7.

ABSTRACT

PURPOSE: The optical testing requirements of plano-protective eyewear in numerous national standards rely on subjective evaluation methods that are negatively impacted by factors such as accommodation, depth of focus, field of view and optical system resolving power differences. The aim of this study was to develop an objective method for testing the optical requirements of plano-protective eyewear.

METHOD: A Shack-Hartmann wavefront sensor and 542 nm collimated laser setup was used to build a Wavefront Analysis Optical Tester (WFAOT). The WFAOT was used to measure the refractive power of 9 calibration lenses and the left oculars of 36 military plano-protective eyewear. Subjective testing of the same samples was done using the telescope method described by American National Standard Institute (ANSI) Z87.1. A dependent t-test was used to evaluate the relationship between protective eyewear refractive powers before and after a two-week interval.SPSS 16 for Windows was used for all statistical analysis.

RESULTS: The spherical powers of the verification lenses measured with WFAOT and ANSI Z87.1 telescope approach are shown in Table 1. There was no difference in refractive powers of the same protective eyewear measured before (M=-0.010, SD=0.018) and after (M=-0.009, SD=0.019) a two-week interval; t(35)= -0.466, p = 0.644.

CONCLUSION: WFAOT is a refractive power measurement method comparable to the telescope approach proposed by ANSI Z87.1.

PMID:35120253 | DOI:10.1167/jov.22.3.7

J Vis. 2022 Feb 1;22(3):3. doi: 10.1167/jov.22.3.3.

ABSTRACT

Certain ocular imaging procedures such as fluoresceine angiography (FA) are invasive with potential for adverse side effects, while others such as funduscopy are non-invasive and safe for the patient. However, effective diagnosis of ophthalmic conditions requires multiple modalities of data and a potential need for invasive procedures. In this study, we propose a novel conditional generative adversarial network (GAN) capable of simultaneously synthesizing FA images from fundus photographs while predicting retinal degeneration. The proposed system addresses the problem of imaging retinal vasculature in a non-invasive manner while utilizing the cross-modality images to predict the existence of retinal abnormalities. One of the major contributions of the proposed work is the introduction of a semi-supervised approach in training the network to overcome the problem of data dependency from which traditional deep learning architectures suffer. Our experiments confirm that the proposed architecture outperforms state-of-the-art generative networks for image synthesis across imaging modalities. In particular, we show that there is a statistically significant difference (p&lt;.0001) between our method and the state-of-the-art in structural accuracy of the translated images. Moreover, our results confirm that the proposed vision transformers generalize quite well on out-of-distribution data sets for retinal disease prediction, a problem faced by many traditional deep networks.

PMID:35120257 | DOI:10.1167/jov.22.3.3

J Vis. 2022 Feb 1;22(3):24. doi: 10.1167/jov.22.3.24.

ABSTRACT

Visual inputs are often highly structured, and statistical regularities of these signals can be used to guide future visuomotor associations and thus optimize behavior. Through a recurrent neural network (RNN) model, human psychophysics, and electroencephalography (EEG), we probed the neural mechanisms for processing probabilistic structures of visual signals to guide behavior. We first constructed and trained a biophysically constrained RNN model to perform a series of probabilistic visual discrimination tasks similar to paradigms designed for humans. Specifically, the training environment was probabilistic such that one stimulus was more probable than the others. We showed that both humans and RNNs successfully learned the stimulus probability and integrated this knowledge into their decisions and task strategy in a new environment. Performance of both humans and RNNs varied with the degree to which the stimulus probability of the new environment matched the formed expectation. In both cases, this expectation effect was more prominent when the strength of sensory evidence was low, suggesting that like humans, the RNNs placed more emphasis on prior expectation (top-down signals) when the available sensory information (bottom-up signals) was limited, thereby optimizing task performance. By dissecting the trained RNNs, we demonstrated how competitive inhibition and recurrent excitation form the basis for neural circuitry optimized to perform probabilistic visual processing.

PMID:35120236 | DOI:10.1167/jov.22.3.24

J Vis. 2022 Feb 1;22(3):60. doi: 10.1167/jov.22.3.60.

ABSTRACT

I will describe evidence for a theory of covert visual search developed within the framework of natural scene statistics and Bayesian statistical decision theory. The theory is unique in several ways: (1) it directly takes into account the statistical properties of natural images, (2) it takes into account the variation in neural processing with retinal location, as well as other known properties of the visual system, and hence contains almost no free parameters, and (3) it includes a principled attentional mechanism that efficiently allocates sensitivity gain across the visual field. This latter mechanism was discovered in experiments measuring covert search in white-noise backgrounds, where the target could appear anywhere within a large search area. In a separate experiment, target detectability (d’) was measured across the visual field when the target location was cued/known. The shape of this “d’ map” was consistent with the theory. The overall performance in the covert search task was also predicted quite well from this d’ map, with no free parameters, assuming parallel unlimited-capacity processing. However, paradoxically, detection accuracy was low in the foveal region, even though it was predicted to be very high. We show that this “foveal neglect” is the expected consequence of efficiently allocating a fixed total attentional sensitivity gain across neurons in visual cortex, rather than across locations in visual space (the traditional assumption). Furthermore, the theory predicts the detailed pattern of covert search performance in the white-noise backgrounds. Finally, I will describe predictions of the theory for search in natural images.

PMID:35120200 | DOI:10.1167/jov.22.3.60

J Vis. 2022 Feb 1;22(3):37. doi: 10.1167/jov.22.3.37.

ABSTRACT

Research has shown that disentangling surface and illuminant colors was possible based on various scene statistics. This study investigates the statistical cues induced by the chromatic effects of interreflections. We present a numerical analysis of ambiguous spectral pairs, in which the spectral power distribution of the illuminant in one scene matched the surface reflectance function in the other scene and vice versa. If the scenes are flat or convex and perfectly matte (Lambertian), the reflected light spectra of both cases are identical. However, the incident light undergoes interreflections for concave scenes. The spectral power of interreflections will be absorbed spectrally in an exponential way, dependent on the number of interreflections. We found that this causes systematic shifts towards the spectral reflectance peaks, resulting in brightness, saturation and hue shifts. Those paired cases’ color differences (CIEDE2000) are so large that humans would be able to observe them if viewed simultaneously. In addition, we find that the color shifts cause qualitatively different gradients for chromatic materials and achromatic light and vice versa. Further psychophysical testing is necessary to see whether the different color shifts for the two cases can be recognized in isolation due to material or light properties. Moreover, the light densities and light vectors are spectrally different for these cases, creating different appearances of 3D objects in non-empty rooms.

PMID:35120223 | DOI:10.1167/jov.22.3.37