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Between-group Comparison (between-group + comparison)
Selected AbstractsOn Distance-Based Permutation Tests for Between-Group ComparisonsBIOMETRICS, Issue 2 2010Philip T. Reiss Summary Permutation tests based on distances among multivariate observations have found many applications in the biological sciences. Two major testing frameworks of this kind are multiresponse permutation procedures and pseudo- F,tests arising from a distance-based extension of multivariate analysis of variance. In this article, we derive conditions under which these two frameworks are equivalent. The methods and equivalence results are illustrated by reanalyzing an ecological data set and by a novel application to functional magnetic resonance imaging data. [source] Effects of physical exercise versus rosiglitazone on endothelial function in coronary artery disease patients with prediabetesDIABETES OBESITY & METABOLISM, Issue 9 2010S. Desch We conducted a three-arm, parallel-group, randomized, controlled trial to compare the effects of rosiglitazone and physical exercise on endothelial function in patients with coronary artery disease and impaired fasting glucose or impaired glucose tolerance over a 6-month period. Group A received rosiglitazone tablets 8 mg daily (n = 16), group B underwent a structured physical exercise programme (n = 15) and group C served as a control group (n = 12). At baseline and after 6 months, brachial artery ultrasound imaging was performed to assess reactive flow-mediated dilation (FMD). Rosiglitazone treatment and exercise both led to significant improvements in insulin resistance at 6 months, whereas no change was observed in control patients. FMD improved significantly in physical exercise patients, whereas no change could be observed in patients receiving rosiglitazone or in the control group. Between-group comparisons also showed a significant relative improvement in FMD in exercise patients compared with rosiglitazone. [source] Efficient Resource Use in Simplified Complete Denture FabricationJOURNAL OF PROSTHODONTICS, Issue 7 2010MMedSci, Yasuhiko Kawai DDS Abstract Purpose: Conventional dentures will remain the only treatment available to most edentulous people for the foreseeable future. In this study, we compared the efficiency of two methods of making complete conventional dentures,the traditional academic standard (T) and a simplified technique (S) used in private practice. We have previously shown that they produce similar levels of patient satisfaction and denture quality. Materials and Methods: Data were gathered during a randomized controlled clinical trial of 122 subjects from initial examination until 6-month follow-up. For this report, the direct costs of providing one set of conventional complete dentures by T or S techniques were estimated. All materials used were recorded and their cost was calculated in Canadian dollars (CAN$). The costs of fabrication in an outside laboratory were added. Clinician's labor time was recorded for every procedure. Between-group comparisons for each clinical procedure were carried out with independent t -tests. The number of patients in each group who needed postdelivery treatment was compared with Chi-square tests. The effect of group assignment and of treatment difficulty on outcomes was analyzed with multiple regression analysis. Results: The mean total cost of the T method was significantly greater than S (CAN$166.3; p < 0.001), and clinicians spent 90 minutes longer (p < 0.001) on clinical care. The difficulty of the case had no significant influence on outcomes. Conclusions: The results indicate that the S method is the more cost-efficient method and that there are no negative consequences that detract from the cost savings. [source] Clinical comparison of two self-directed bleaching systemsJOURNAL OF PROSTHODONTICS, Issue 4 2003Katherine Karpinia DMD Purpose This randomized clinical trial compared the clinical efficacy and tolerability of 2 marketed self-directed vital tooth-whitening systems. Materials and Methods Balancing for baseline tooth color, self-reported coffee/tea use, and age, 57 adult volunteers were randomized to either a whitening strip containing 6% hydrogen peroxide or a tray-based 10% carbamide peroxide/dentifrice/mouth rinse combination system. Following the manufacturer' s directions, the strip group bleached twice daily for 30 minutes, whereas the tray group bleached twice daily for 20,30 minutes, preceded by tooth brushing with a whitening dentifrice and followed by mouth rinsing with a whitening solution. Treatment extended for 14 days, with evaluation at day 7 and again at day 14. Whitening response was measured objectively as L*a*b* from standardized digital images of maxillary anterior teeth. Tolerability was assessed by oral examination and subject interview. Efficacy comparisons were made using analysis of covariance, whereas tolerability was compared using the nonparametric Wilcoxon rank-sum test. Results Both treatments resulted in statistically significant (P < 0.01) improvements from baseline for all color parameters. For between-group comparisons, the 6% hydrogen peroxide strips yielded a nearly 3-fold reduction in yellowness (,b*), a nearly 2-fold improvement in lightness (,L*), 2.6 times greater redness reduction (,a*), and a more than 2-fold change in overall color (,E*) compared to the tray-based combination system. Between-group comparisons were statistically significant for the all color parameters at both the day 7 and day 14 evaluations (P < 0.001). In general, 7-day use of the whitening strips provided significantly greater color improvement relative to the combination dentifrice/gel/rinse system at day 14. In addition, the groups differed significantly (P < 0.05) in bleaching tolerability severity-days, with the strip system demonstrating better overall tolerability compared to the combination system. Conclusions The single-step 6% hydrogen peroxide strips demonstrated better overall clinical response, in terms of both tooth-whitening efficacy and tolerability, than the multiple-step tray-based combination system. [source] Histological effects of tazarotene 0·1% cream vs. vehicle on photodamaged skin: a 6-month, multicentre, double-blind, randomized, vehicle-controlled study in patients with photodamaged facial skinBRITISH JOURNAL OF DERMATOLOGY, Issue 6 2004L.A. Machtinger Summary Background, Topical tazarotene has been shown to offer efficacy in ameliorating multiple effects of photodamage. Objectives, To evaluate the histological effects of tazarotene cream on photodamaged skin. Methods, In this multicentre, double-blind, randomized, vehicle-controlled study, 50 patients with photodamaged facial skin (at least mild fine wrinkling and mottled hyperpigmentation, with at least one of these being moderate) were randomized to apply tazarotene 0·1% cream or vehicle cream to their face, once daily for 24 weeks. Results, Blinded assessments showed that tazarotene was less likely than vehicle to be associated with an increase in keratinocytic and melanocytic atypia, and more likely than vehicle to be associated with a reduction in atypia. Between-group comparisons in distribution of change from baseline categories of severity were in favour of tazarotene (P = 0·055 for keratinocytic atypia, P = 0·034 for melanocytic atypia, and P < 0·001 for the number of granular cell layers). Compared with vehicle, tazarotene was associated with an increase in epidermal polarity (P = 0·008) and epidermal thickness (P = 0·012), and a tendency for stratum corneum compaction. Tazarotene was also associated with widened intercellular spaces (reported as epidermal oedema) relative to vehicle (P < 0·001). Conclusions, Treatment of photodamaged skin with tazarotene is associated with an amelioration of keratinocytic and melanocytic atypia, an improvement in epidermal polarity, and an increase in epidermal thickness. [source] The Chorus Song of Cooperatively Breeding Laughing Kookaburras (Coraciiformes, Halcyonidae: Dacelo novaeguineae): Characterization and Comparison Among GroupsETHOLOGY, Issue 1 2004Myron C. Baker I studied vocalizations of laughing kookaburras in Western Australia by sampling the laugh-song choruses of eight different groups and the isolated vocalizations of four individuals of this cooperatively breeding species. These data provided a description of the acoustic structure of vocal elements of the laugh song and a between-group comparison of laugh choruses. I identified six different categories of syllables: some syllable types appear graded with modal forms predominating. Group choruses were produced by several birds vocalizing simultaneously, usually following initiation by a single bird producing one of two typical introductory sets of syllable repetitions. Statistical analyses of samples of mid-chorus vocalizations of kookaburra groups revealed that the samples from each of the eight groups clustered in principal coordinate space and the group clusters segregated from each other to a significant degree. Linear discriminant analysis assigned 24 of the 25 samples to their correct groups. These results suggest that there is group-specific vocal signature information in the laugh chorus. The within-group similarity and between-group differences may result from heritable variation or from imitation learning. Observations of the contexts of the laugh chorus vocalization supported the interpretations of others that the chorus song is involved in group advertisement of territory occupancy and in defense of the communal borders. [source] Individual differences in socioaffective skills influence the neural bases of fear processing: The case of alexithymiaHUMAN BRAIN MAPPING, Issue 10 2010Lydia Pouga Abstract Being exposed to fear signals makes us feel threatened and prompts us to prepare an adaptive response. In our previous studies, we suggested that amygdala (AMG) and premotor cortex (PM) play a role in the preparation of the observers' motor response required by the situation. The present experiment aimed at assessing how interindividual differences in alexithymia,a personality trait associated with deficits in emotional reactivity and regulation,influence the neural network associated with the perception of fear. Using fMRI, we scanned 34 healthy subjects while they were passively observing fearful body expressions. Applying a dimensional approach, we performed correlation analyses between fear-related brain areas and alexithymia scores among all participants. Using a categorical approach, we conducted a between-group comparison (13 high vs. 12 low-alexithymia subjects). Our results were threefold. First, the right AMG activity in response to fearful stimuli was negatively correlated with the level of difficulty to identify emotions. Second, PM activity was linked to reduced subjective emotional reactivity. Third, the between-group comparison revealed greater activity in anterior cingulate cortex (ACC) for high than low-alexithymia scorers. Moreover, the relationship between ACC and PM was in opposite direction in individuals with high (negative link) and low (positive link) alexithymia. Therefore, compared to our previous findings, we hereby further reveal how ACC interacts with PM to sustain self-regulation of one's own emotional state in response to threatening social signals. Moreover, this neural mechanism could account for the description of the "cold-blooded" personality of individuals with alexithymia. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc. [source] Clinical trial: a nutritional supplement Viusid, in combination with diet and exercise, in patients with nonalcoholic fatty liver diseaseALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 10 2009E. VILAR GOMEZ Summary Background, Nonalcoholic fatty liver disease (NAFLD) is a significant health problem for which there is no universally accepted pharmacological treatment. The combination of weight loss and antioxidant drugs to ameliorate insulin resistance and improve steatosis, inflammation and fibrosis provides the rational for therapeutic trials. Aim, To evaluate the efficacy and safety of a nutritional supplement Viusid in association with diet and exercise for NAFLD. Methods, A randomized, controlled and parallel-group trial was conducted at a tertiary care academic centre (National Institute of Gastroenterology, Havana, Cuba). We randomly assigned 60 patients with liver biopsy-proven NAFLD to 6 months of treatment with a hypocaloric diet plus aerobic exercise daily and three Viusid sachets daily or a hypocaloric diet and exercise. Endpoints were improvement in the NAFLD activity score (NAS), fibrosis and normalization of serum aminotransferase levels. Results, A significant improvement in steatosis, necroinflammation and fibrosis was seen in each group of treatment (P < 0.01 for each feature). The Viusid group, as compared with the control group, significantly reduced the mean of NAS [from 4.18 to 0.54 points in the Viusid group vs. 4.45 to 2.2 points in the control group (P < 0.001)]. On between-group comparison, Viusid was found to be associated with a significantly greater improvement in steatosis (P < 0.001), ballooning (P = 0.002) and lobular inflammation (P = 0.025), but not in fibrosis (P = 0.07). Viusid was well tolerated. Conclusions, Our results indicate that treatment with diet and exercise leads to a notable improvement in the histological features of NAFLD; however, the administration of Viusid intensifies the improvements of histological findings, especially of steatosis and inflammation. [source] Hyperfrontality in patients with schizophrenia during saccade and antisaccade tasks: A study with fMRIPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 2 2009Mai Fukumoto-Motoshita mms Aims:, Antisaccadic eye movements, requiring inhibition of a saccade toward a briefly appearing peripheral target, are known to be impaired in schizophrenia. Previous neuroimaging studies have indicated that patients with schizophrenia show diminished activations in the frontal cortex and basal ganglia. These studies used target fixation as a baseline condition. However, if the levels of brain activities at baseline are not compatible between patients and healthy subjects, between-group comparison on antisaccade-related activations is consequently invalidated. One possibility is that patients with schizophrenia may present with greater activation during fixation than healthy subjects. In order to examine this possibility, here we investigated brain activities associated with antisaccade in the two groups without using target fixation at baseline. Methods:, Functional brain images were acquired during prosaccades and antisaccades in 18 healthy subjects and 18 schizophrenia patients using a box-car functional magnetic resonance imaging design. Eye movements were measured during scanning. Results:, In the patient group, the elevated activities in the dorsolateral prefrontal cortex (DLPFC) and thalamus, normally seen in antisaccade tasks relative to saccade tasks, were no longer observed. Moreover, in normal subjects, activities in the DLPFC and thalamus were greater during the antisaccade task than during the saccade task. In patients, no such difference was observed between the two tasks, suggesting that these brain regions are likely to be highly activated even by a simple task such as fixation. In particular, the DLPFC and thalamus in patients were not activated at a level commensurate with the difficulty of the tasks presented. Conclusions:, From these results, it is suggested that schizophrenia entails dysfunctions in the fronto-striato-thalamo-cortical network associated with motor function control. [source] A randomized, single-blind comparison of topical clindamycin + benzoyl peroxide and adapalene in the treatment of mild to moderate facial acne vulgarisBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2008A. Langner Summary Background, Antibiotics are often combined with other agents to provide topical acne treatments that are effective against both inflammatory and noninflammatory lesions and minimize the development of antibiotic resistance. Retinoids and associated treatments also have anti-inflammatory activity and decrease microcomedo formation. To date, few direct comparisons of these different acne treatments have been conducted. Objectives, To compare the clinical effectiveness of two treatments for facial acne: a ready-mixed once-daily gel containing clindamycin phosphate 10 mg mL,1 + benzoyl peroxide 50 mg mL,1 (CDP + BPO; Duac®; Stiefel, High Wycombe, U.K.) and a once-daily gel containing adapalene 0·1% (ADA; Differin®; Galderma, Watford, U.K.). Methods, In this assessor-blind, randomized study; 65 patients were treated with CDP + BPO once daily and 65 patients with ADA once daily. The treatment period was 12 weeks and lesion counts, acne grade and global improvement were assessed at weeks 1, 2, 4, 8 and 12. Results, CDP + BPO showed an earlier onset of action with a faster significant reduction in inflammatory and total lesion counts than ADA. A between-group comparison of the percentage change from baseline showed that CDP + BPO was statistically significantly superior to ADA from week 1 onwards both for inflammatory lesions (P , 0·001) and for total lesions (P , 0·004). While 76% of inflammatory lesions remained at week 2 for patients using ADA, in contrast, only 55% of inflammatory lesions remained at week 2 in the CDP + BPO group, resulting in a treatment effect of 1·38. Thus CDP + BPO removed 38% more inflammatory lesions than ADA at this timepoint. The trend in favour of CDP + BPO, although less marked, continued to the end of the study. CDP + BPO was better tolerated than ADA, with a greater proportion of ADA-treated patients experiencing treatment-related adverse events. Adjunctive topical or oral agents and their impact on acne were not studied in this trial. Due to product differences, this study could not be double blinded but was only single (assessor) blinded. Conclusions, CDP + BPO and ADA are both effective treatments for acne, but CDP + BPO has a significantly earlier onset of action, is significantly more effective against inflamed and total lesions and is better tolerated, which should improve patient compliance. [source] Uses and Gratifications of the Web among StudentsJOURNAL OF COMPUTER-MEDIATED COMMUNICATION, Issue 1 2000Samuel Ebersole This study was designed to explore how some students in ten public schools view the WWW and how their attitudes and opinions affect their use of this new medium in an educational context. An exploratory principal components analysis of forty use statements resulted in an eight factor solution. Additionally, student responses to a computer-administered survey instrument were collected and analyzed revealing significant differences in the way that students describe their use of the WWW. Gender, grade level, and amount of time spent using the WWW were used to create between-group comparisons of the WWW use categories that made up the computer-administered survey instrument. The final phase of data analysis was a content analysis of sites visited by students. A total of 123,071 URLs were collected from the computers used to administer the computer survey instrument. These were reduced to a total of 500 sites that were reviewed by media specialists. Students were found to be visiting commercial sites at a much higher proportion than those in other domains. Also, the commercial sites received the lowest rating for "suitability for academic research" of all the domain names. And while students reported their purpose for using the WWW as "research and learning" fifty-two percent of the time, the coders found only twenty-seven percent of the sampled sites to be "suitable" for that purpose. [source] Clinical comparison of two self-directed bleaching systemsJOURNAL OF PROSTHODONTICS, Issue 4 2003Katherine Karpinia DMD Purpose This randomized clinical trial compared the clinical efficacy and tolerability of 2 marketed self-directed vital tooth-whitening systems. Materials and Methods Balancing for baseline tooth color, self-reported coffee/tea use, and age, 57 adult volunteers were randomized to either a whitening strip containing 6% hydrogen peroxide or a tray-based 10% carbamide peroxide/dentifrice/mouth rinse combination system. Following the manufacturer' s directions, the strip group bleached twice daily for 30 minutes, whereas the tray group bleached twice daily for 20,30 minutes, preceded by tooth brushing with a whitening dentifrice and followed by mouth rinsing with a whitening solution. Treatment extended for 14 days, with evaluation at day 7 and again at day 14. Whitening response was measured objectively as L*a*b* from standardized digital images of maxillary anterior teeth. Tolerability was assessed by oral examination and subject interview. Efficacy comparisons were made using analysis of covariance, whereas tolerability was compared using the nonparametric Wilcoxon rank-sum test. Results Both treatments resulted in statistically significant (P < 0.01) improvements from baseline for all color parameters. For between-group comparisons, the 6% hydrogen peroxide strips yielded a nearly 3-fold reduction in yellowness (,b*), a nearly 2-fold improvement in lightness (,L*), 2.6 times greater redness reduction (,a*), and a more than 2-fold change in overall color (,E*) compared to the tray-based combination system. Between-group comparisons were statistically significant for the all color parameters at both the day 7 and day 14 evaluations (P < 0.001). In general, 7-day use of the whitening strips provided significantly greater color improvement relative to the combination dentifrice/gel/rinse system at day 14. In addition, the groups differed significantly (P < 0.05) in bleaching tolerability severity-days, with the strip system demonstrating better overall tolerability compared to the combination system. Conclusions The single-step 6% hydrogen peroxide strips demonstrated better overall clinical response, in terms of both tooth-whitening efficacy and tolerability, than the multiple-step tray-based combination system. [source] Symptoms and quality of life in obese children and adolescents with non-alcoholic fatty liver diseaseALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2010K. D. KISTLER Aliment Pharmacol Ther,31, 396,406 Summary Background, Data on the quality of life (QOL) of children with non-alcoholic fatty liver disease (NAFLD) are needed to estimate the true burden of illness in children with NAFLD. Aim, To characterize QOL and symptoms of children with NAFLD and to compare QOL in children with NAFLD with that in a sample of healthy children. Methods, Quality of life and symptoms were assessed in children with biopsy-proven NAFLD enrolled in the NASH Clinical Research Network. PedsQL scores were compared with scores from healthy children. For children with NAFLD, between-group comparisons were made to test associations of demography, histological severity, symptoms and QOL. Results, A total of 239 children (mean age 12.6 years) were studied. Children with NAFLD had worse total (72.8 vs. 83.8, P < 0.01), physical (77.2 vs. 87.5, P < 0.01) and psychosocial health (70.4 vs. 81.9, P < 0.01) scores compared with healthy children. QOL scores did not significantly differ by histological severity of NAFLD. Fatigue, trouble sleeping and sadness accounted for almost half of the variance in QOL scores. Impaired QOL was present in 39% of children with NAFLD. Conclusions, Children with NAFLD have a decrement in QOL. Symptoms were a major determinant of this impairment. Interventions are needed to restore and optimize QOL in children with NAFLD. [source] Sorting out successful failures: Exploratory analyses of factors associated with academic and behavioral outcomes of retained studentsPSYCHOLOGY IN THE SCHOOLS, Issue 4 2001Phillip Ferguson This prospective longitudinal study followed a sample of 106 kindergarten students through 11th grade examining the effects of family characteristics, school readiness, socialization, and student demographics on academic achievement and behavioral adjustment outcomes. These educational outcomes were contrasted among four groups consisting of: 1) early grade retainees; 2) transitionally placed retained students; 3) students recommended for transitional placement, but promoted; and 4) regularly promoted students. While previous studies examining the efficacy of early grade retention focus exclusively on between-group comparisons, this study examines the family and individual characteristics of successful and unsuccessful retained students by including both between-group and within-group effects on academic and behavioral outcomes. The results of this study demonstrate that retained students' initial school readiness, socioeconomic status, mother's level of education, parental value of education, kindergarten personal-social functioning, and chronological age are distinctly associated with subsequent academic or behavioral outcomes. Variables associated with relative educational success following early failure are delineated and research implications are discussed. © 2001 John Wiley & Sons, Inc. [source] Increased rates of white matter hyperintensities in late-onset bipolar disorderBIPOLAR DISORDERS, Issue 7 2008Jaqueline Hatsuko Tamashiro Objectives:, Magnetic resonance imaging (MRI) studies have reported an increased frequency of white matter hyperintensities (WMH) in association with late-onset (LO) depression, and this has supported the notion that vascular-related mechanisms may be implicated in the pathophysiology of LO mood disorders. Recent clinical studies have also suggested a link between LO bipolar disorder (LO-BD) and cerebrovascular risk factors, but this has been little investigated with neuroimaging techniques. In order to ascertain whether there could be a specific association between WMH and LO-BD, we directly compared WMH rates between LO-BD subjects (illness onset , 60 years), early-onset BD subjects (EO-BD, illness onset <60 years), and elderly healthy volunteers. Methods:, T2-weighted MRI data were acquired in LO-BD subjects (n = 10, age = 73.60 ± 4.09), EO-BD patients (n = 49, age = 67.78 ± 4.44), and healthy subjects (n = 24, age = 69.00 ± 7.22). WMH rates were assessed using the Scheltens scale. Results:, There was a greater prevalence of WMH in LO-BD patients relative to the two other groups in the deep parietal region (p = 0.018) and basal ganglia (p < 0.045). When between-group comparisons of mean WMH scores were conducted taking account of age differences (ANCOVA), there were more severe scores in LO-BD patients relative to the two other groups in deep frontal and parietal regions, as well as in the putamen (p < 0.05). Conclusions:, Our results provide empirical support to the proposed link between vascular risk factors and LO-BD. If extended in future studies with larger samples, these findings may help to clarify the pathophysiological distinctions between bipolar disorder emerging at early and late stages of life. [source] Redefining functional models of basal ganglia organization: Role for the posteroventral pallidum in linguistic processing?MOVEMENT DISORDERS, Issue 11 2004Brooke-Mai Whelan PhD Abstract Traditionally the basal ganglia have been implicated in motor behavior, as they are involved in both the execution of automatic actions and the modification of ongoing actions in novel contexts. Corresponding to cognition, the role of the basal ganglia has not been defined as explicitly. Relative to linguistic processes, contemporary theories of subcortical participation in language have endorsed a role for the globus pallidus internus (GPi) in the control of lexical,semantic operations. However, attempts to empirically validate these postulates have been largely limited to neuropsychological investigations of verbal fluency abilities subsequent to pallidotomy. We evaluated the impact of bilateral posteroventral pallidotomy (BPVP) on language function across a range of general and high-level linguistic abilities, and validated/extended working theories of pallidal participation in language. Comprehensive linguistic profiles were compiled up to 1 month before and 3 months after BPVP in 6 subjects with Parkinson's disease (PD). Commensurate linguistic profiles were also gathered over a 3-month period for a nonsurgical control cohort of 16 subjects with PD and a group of 16 non-neurologically impaired controls (NC). Nonparametric between-groups comparisons were conducted and reliable change indices calculated, relative to baseline/3-month follow-up difference scores. Group-wise statistical comparisons between the three groups failed to reveal significant postoperative changes in language performance. Case-by-case data analysis relative to clinically consequential change indices revealed reliable alterations in performance across several language variables as a consequence of BPVP. These findings lend support to models of subcortical participation in language, which promote a role for the GPi in lexical,semantic manipulation mechanisms. Concomitant improvements and decrements in postoperative performance were interpreted within the context of additive and subtractive postlesional effects. Relative to parkinsonian cohorts, clinically reliable versus statistically significant changes on a case by case basis may provide the most accurate method of characterizing the way in which pathophysiologically divergent basal ganglia linguistic circuits respond to BPVP. © 2004 Movement Disorder Society [source] | ||||||||||||||||