Osteoarthritis (OA) of the knee affects between 5.4% and 38% of older adults and this prevalence is increasing as the population ages and becomes more obese. As health costs rise, it is important to have accurate and cost-effective methods to assess knee OA and the risk for OA. One risk factor for progression of knee OA is lower extremity (LE) frontal-plane malalignment. The first goal of this thesis was to assess the suitability of knee radiographs and LE photographs for the estimation of frontal-plane LE alignment. In the first study, several versions of the femoral shaft-tibial shaft (FS-TS) angle, assessed from knee radiographs, were compared to the hip-knee-ankle (HKA) angle, assessed from full-length radiographs. We concluded that the FS-TS angle is not a recommended substitute for the HKA angle, because the association between the two measures differs depending on alignment, OA severity and the method of determining the FS-TS angle. In the second study, the hip-knee-ankle angle determined from a pelvis-to-ankle photograph (HKA-P) was assessed for its ability to estimate the HKA angle. The HKA-P angle was reliable and highly correlated to the HKA. It therefore shows promise as an accurate and cost-effective assessment tool for the estimation of LE alignment. Commonly-used grading scales for the severity of knee OA seen on a radiograph emphasize just one feature of OA; therefore the second goal of this thesis was to assess the psychometric properties of the unicompartmental osteoarthritis grade (UCOAG), a composite scale which grades several features of OA in the tibiofemoral (TF) compartment. In the third and fourth studies, the reliability, validity and sensitivity to change of the UCOAG scale was assessed and compared to two commonly-used scales (Kellgren-Lawrence and Osteoarthritis Research Society International joint space narrowing). The UCOAG scale showed moderate to excellent reliability. All three scales demonstrated comparable validity and sensitivity to change. The UCOAG is therefore recommended for the assessment of OA severity and change over time. This research provides evidence for the use of accurate and cost-effective measures to assess LE alignment using photographs, and TF OA severity using radiographs, for clinical assessment and research purposes. / Thesis (Ph.D, Rehabilitation Science) -- Queen's University, 2013-09-26 13:21:06.097

Faculty of Sciences School of Anatomical Sciences 0202721m slyviakamanzi@yahoo.com / This study primarily seeks to confirm two systems of classifying the sulci of the frontal operculum1 (F3): the radiologically derived system of Ebeling et al (1989) involving four Types of Sulcal Connections, and the anatomical classification of the anterior rami of the lateral fissure, involving three patterns. Sulcal- and intersulcal- lengths are also considered. The sample consisted of 220 cadaveric hemispheres; 65 of which were whole brains (control category); and 90 consisting of equal numbers of separate right- and lefthemispheres (case category). Specimens were orientated by examining relevant features of: the lateral fissure; the postcentral sulcus; and the central fissure. Features of the remaining boundary sulci (precentral sulcus / sulci, and inferior frontal sulcus) of F3 were also considered. The focus was on examining the: frequency of occurrence, shape, and connections of the sulci of the F3. The sulci of F3 were designated as: major sulci [anterior ascending (AAR)- and anterior horizontal (AHR)- rami, and stem of the anterior rami when present); and accessory sulci (sulci of the –pars opercularis and –pars triangularis). Sulcal lengths were measured using thread, with needles as anchors. Intersulcal lengths were recorded as straight-line distances between parallel pins inserted into the sulci of the frontoparietal operculum. Specimens fixed outside the cranial cavity were excluded from measurement. The reliability of the data was monitored, by repeating the observations. The two systems of classification were broadly confirmed. The criteria for the Types of Sulcal Connections were modified in view of the findings on double precentral sulci and the connections of the opercular sulcus (which occurred as either one or as two sulci). A sulcus of the pars triangularis (which occurred as either one, two, or as three sulci) was found to be a useful landmark. The Chi-square test was applied to the data in the two systems of classification. There were no significant interhemispheric differences with respect to the incidences of: Types 1-4 of Sulcal Connections, or Patterns of the Anterior Rami (I, Y, and VU). Sulcal lengths were similar to that reported by Ono et al (1990). The Student t-test was applied to sample sizes 18 and above. No significant interhemispheric differences, in the lengths of the sulci that were considered, were found. A significant 1 The definition of the frontal operculum as the inferior frontal gyrus only, is used for the purposes of this study. The frontal operculum may also be abbreviated as F3. v difference was found in two instances when comparing the case- and control- categories. Intersulcal distances are reported on in the frontal- and frontoparietal- operculum.

Este estudo teve por finalidade investigar a frequência e intensidade dos Sistemas Frontais (SF) avaliando-os com os episódios ENOS (El Niño Oscilação Sul) para o período da Primavera (SON) de 2000 a 2010 sobre o Estado do Rio Grande do Sul (RS). As análises mostraram que os anos em que se tem a menor ocorrência de SF estão associados principalmente a eventos de La Niña Fraco e Neutralidade. Em contrapartida, um número maior de Sistemas Frontais foi verificado com relação aos episódios de El Niño Moderado e Neutralidade. Especificamente, no que se refere à questão mensal, percebeu-se que no mês de Outubro há uma maior influência dos Sistemas Frontais do que em Setembro e Novembro. Outro fator pertinente e evidenciado deu-se pelas comparações entre o período escolhido (no qual não ocorreram eventos fortes) e os episódios de ENOS Fortes. Notou-se, neste caso, que não ocorreram variações impactantes no número de Sistemas Frontais, embora se tenha o conhecimento dos efeitos e alterações existentes nos padrões de circulação atmosférica devido à atuação dos fenômenos de escala interanual. Ainda, tendo a necessidade de ampliar a gama de entendimento, foi realizada uma abordagem com relação ao comportamento da precipitação em seis sub-regiões do Estado, onde se observou de forma geral, um aumento da precipitação em praticamente todas as áreas do RS, quando comparado com a média Histórica. Com isso, ressaltou-se que os volumes mensais abaixo da média Histórica estão ligados a episódios de Neutralidade. Já a normalidade do regime de precipitação, mostrou-se interligado em média para todas as regiões ao evento de El Niño e por último, as precipitações acima da normal climatológica estão mais presentes em condições de El Niño, mais especificamente de intensidade Moderada. Dentre as sub-regiões analisadas, destacou-se a parte Oeste do Estado por ter apresentado uma maior intensidade nos volumes de precipitação. Outro fator importante analisado foram os valores percentuais das precipitações derivadas dos sistemas frontais. Levando-se em conta a média das avaliações, verificou-se que as sub-regiões Sul e Sudoeste do Rio Grande do Sul são as mais influenciadas pelas passagens dos Sistemas Frontais, enquanto os menores impactos na precipitação podem ser notados nas regiões Central e Norte do Rio Grande do Sul. Além disso, realizou-se um estudo de caso para avaliar o comportamento dos Sistemas Frontais em episódios de ENOS diferentes, nos campos de pressão atmosférica e temperatura do ar. Logo, averigou-se que em um ano de Neutralidade, as passagens de SF sobre o Estado costumam ser mais prolongadas em sua duração de tempo, permanecendo mais dias, com algumas variações significativas nos campos meteorológicos observados. Enquanto para um ano referente à condição de El Niño Moderado, os Sistemas Frontais possuem, na maioria dos casos, uma duração de tempo menor, consequentemente com menores variações na temperatura e pressão. / This study aimed to investigate the frequency and intensity of the frontal systems (FS) evaluating them with respect to the episodes of El Niño – South Oscillation (ENSO) for the spring season (SON) from 2000 to 2010, over the state of Rio Grande do Sul (RS - Brazil). The analysis showed that the years having a smaller incidence of SF are mainly associated to events of weak La Nina and neutrality. In contrast, a larger number of frontal systems were observed with respect to episodes of moderate El Nino and neutrality. Specifically with relation to the monthly aspect, it was noticed that there is a major influence of the frontal systems in October than in September and November. Another inherent and evidenced factor was given by the comparisons between the selected period (with no occurrence of strong events) and the Strong ENSO episodes. In this case it was noticed that there has not occurred impacting variations in the number of frontal systems although the effects and changes of the atmospheric circulation patterns due to the action of the interannual scale phenomena are known. Further, to enlarge the range of understanding, it was made one approach relating to the precipitation behavior in six sub regions of the state where in general it was observed an increase in the precipitation almost in all areas of the RS when compared to the historic average. Thus, the monthly volumes below the historic average are linked to neutral episodes. Otherwise, the normal precipitation regime, on average, was proved to be interconnected for all regions to the event El Niño, and finally the rainfall above the climatology are more common in El Niño conditions, specifically with Moderate intensity. In this manner, considering the analyzed sub regions, the west part of the state has presented a higher intensity of precipitation volumes. Another important factor analyzed were the percentage values of rainfall derived from frontal systems. Taking into account the average of the evaluations, it was found that the South and southwest sub-region of Rio Grande do Sul is the most influenced by passages from the SF, while smaller impacts on precipitation can be noticed in the Central and North regions. In addition, it was realized a case study to evaluate the behavior of frontal systems in different episodes of ENSO, with respect to the fields of atmospheric pressure and air temperature. Thus, it was found that in a year of neutrality, the frontal systems crossings on the state tend to be more prolonged, remaining more days, with some significant variations in the observed meteorological fields. While for a year related to the condition of Moderate El Nino the frontal systems have, in mosta cases, a shorter duration, thus with minor variations in temperature and pressure.

The principal aim of this thesis was to test the conjecture of Schacter et al. (1995) that the false memory effect in the Deese-Roediger-McDermott (DRM) paradigm is generated by errors in source monitoring and is mediated by frontal lobe circuits. In support of their conjecture, Schacter et al. cited evidence from elderly populations with presumed frontal dysfunction, however this thesis studied children over an age range over which the frontal lobes are believed to be maturing. This thesis represents the first attempt to specifically test Schacter�s hypothesis based on the developmental trajectory of �frontal� functioning. Moreover, the use of a developmental trajectory in such a manner is relatively novel, and a key issue within this thesis is how to operationalise �frontal� functioning in the sense intended by Schacter et al. Extrapolating from Schacter�s conjecture, it was predicted that the strength of the false memory effect is directly proportional to the degree of frontal maturation, as estimated by both chronological age and by performance on a range of neuropsychological tests of �frontal� executive functioning. False memory and executive functioning were compared in children aged 8 to 12 years and in adults using a modified DRM paradigm with a source monitoring extension after Payne et al. (1996). The modified DRM elicited false memory effects comparable to those reported in adolescents by Newstead and Newstead (1998) and in adults by Roediger and McDermott (1995) and by Payne et al. (1996). Three experiments that demonstrate a strong developmental trajectory for false memory effect are reported, but the pattern of results is not consistent with all of the premises of the conjecture. Although false recognition rates increased significantly with age, source monitoring accuracy did not change across the age groups. Consistent with the principal assertion of the conjecture by Schacter et al., age and a general �frontal� factor were found to be significantly related to the size of the false memory effect. In addition, veridical memory performance was always a predictor of false memory performance. The IAR (Underwood, 1965) theory can best account for the significant covariation between veridical and false memory development, as well as being able to account for the dissociation between false memory and source monitoring.

Ostracism arouses negative affect. However, little is known about variables that influence the intensity of these negative affective responses. Two studies seek to fill this void by incorporating work on approach- and withdrawal-related emotional states and their associated cortical activations. Study 1 found that following ostracism, anger related directly to relative left frontal cortical activation. Study 2 used unilateral hand contractions to manipulate frontal cortical activity prior to an ostracizing event. Righthand contractions, compared to left-hand contractions, caused greater relative left frontal cortical activation during the hand contractions as well as during ostracism. Also, righthand contractions caused more self-reported anger in response to being ostracized. Within-condition correlations revealed patterns of associations between ostracisminduced frontal asymmetry and emotive responses to ostracism consistent with Study 1. Taken together, these results suggest that asymmetrical frontal cortical activity affects angry responses to ostracism, with greater relative left frontal cortical activity being associated with increased anger.

The multidimensional nature of the frontal lobes serves to organize and coordinate brain functioning, playing a central and pervasive role in human cognition. The organizational and strategic nature of frontal lobe functioning affects memory processes by enhancing the organization of to-be-remembered information. Among the specific memory systems presumed to be based on anterior cerebral structures is the temporal organization of memory. An essential component of memory that involves temporal organization is sequential ordering. The acquisition of abilities thought to be mediated by the frontal lobes, including sequential memory, unfolds throughout childhood, serving to condition patterns of behavior for the rest of the brain. Development of the frontal regions of the brain is known to continue through late adolescence and into early adulthood, in contrast to the earlier maturation of other cortical regions. The purpose of the present study was to evaluate the development of sequential memory and to compare such findings to what currently is known regarding the development of frontal lobe functioning. Through an analysis of the previously collected standardization data of the Test of Memory and Learning (TOMAL; Reynolds & Bigler, 1994), a developmental function depicting the maturational process of sequential memory was derived. This model was then compared to an overall representative model of frontal lobe functioning. Results indicated a staging of development that begins in early childhood with the maturation of sequential memory continuing, although at a decreased rate, into early adolescence. The greatest period of development in sequential memory was evident between 5 and 8 years of age. The rate of development then decreased, and a continued deceleration of maturation continued throughout the age span examined. Gender was not found to be a significant predictor of developmental performance on sequential memory tasks. The results of the present study are consistent with previous findings that have suggested that the development of frontal functions occurs in a step-wise fashion with greatest period of development in frontal lobe functioning occurring at the 6- and 8-year old levels, with more moderate effects between the ages of 9 and 12 and performance approximating adult levels during adolescence.

Whereas some researchers claim that the holistic processing of the right hemisphere is essential for contextual integration in language pragmatics (Myers, 2001, Myers, 2005), results of other studies point to involvement of executive processes of the frontal lobes (McDonald & Pearce, 1998; Bernicot & Dardier, 2001). This study examined the role of frontal lobes in language pragmatics by testing performance of young adults and older adults on selected standardized pragmatic inferences called 'implicitures'. Implicitures were first presented free-standing and then embedded in contexts that either supported (enabling contexts) or cancelled (cancelling contexts) their preferred meaning. First, implicitures were examined using behavioral reaction time measures in young adults. The second part of the project addressed the question about involvement of frontal lobes in language pragmatics by testing older adults with varying degrees of frontal function on processing of implicitures. Finally, event-related potential responses to implicitures with and without context in young adults were explored. Results revealed a strong relationship between frontal lobes and performance on implicitures in canceling contexts in older adults. There was no significant effect for free-standing implicitures and implicitures presented in enabling contexts. In addition, an N400 was observed to free-standing implicitures, but implicitures in context elicited a negative component in the later 400 ms window at the anterior sites. These results indicate that frontal lobes are important for pragmatic processing requiring integration of linguistic context with an utterance for the correct interpretation. Consequences of our findings for models of impliciture processing and accounts of neural architecture underlying language pragmatics are considered.

Frontal encephalographic (EEG) alpha asymmetry has been proposed as a measure of the relative difference in average cortical activity between the right and left anterior cortex, where this difference is taken as a physiological marker of trait and state level variables associated with affect. The validity of asymmetry as an indicator of both physiological and psychological variables is in part determined by the psychometric properties of asymmetry scores. The present studies focus on the psychometric assessment of frontal alpha asymmetry measured during rest. The first study involves a novel approach in the assessment of the internal consistency reliability of asymmetry scores. Previous studies estimated internal consistency reliability via Cronbach's alpha, using a relatively small set of asymmetry score that summarized activity over segments of the EEG data (e.g. one minute). Such an approach, however, will create estimates dependent on the number of segments utilized rather than the total amount of data recorded. Thus in the first study, individual FFT epochs were treated as items, thereby maximizing the total number of items used to estimate internal consistency reliability. Results of this study suggest internal consistency reliability is greater than previously reported, and as such, the duration of resting EEG data necessary to achieve a reasonable reliability criterion may be shorter than the current standard. In the second study, asymmetry scores were assessed as a specific case of difference scores, which are susceptible to a statistical artifact associated with differences in true-score variance for the component measures. Predicted asymmetry scores associated with the statistical artifact were obtained by estimating the true-score variance of right and left alpha power. The use of hierarchical linear regression showed some influence of the statistical artifact on the relationship between asymmetry scores and a measure of depressive severity, suggesting that some caution may be warranted in interpreting asymmetry results with relatively small effect sizes.

No description available.

Traumatic brain injury (TBI) is a leading cause of disability globally. Cognitive deficits represent the primary source of on-going disability in this population, yet the mechanisms of these deficits remain poorly understood. Here functional and diffusion-weighted imaging techniques were employed to characterize the mechanisms of neurofunctional change following TBI and their relationship to cognitive function. TBI subjects who had sustained moderate to severe brain injury, demonstrated good functional and neuropsychological recovery, and screened positive for diffuse axonal injury but negative for focal brain lesions were recruited for the project. TBI subjects and matched controls underwent structural, diffusion-weighted and functional MRI. The functional scanning paradigm consisted of a complex working memory task with both load and executive control manipulations. Study one demonstrated augmented functional engagement for TBI subjects relative to healthy controls associated with executive control processing but not maintenance operations within working memory. In study two, multivariate neuroimaging analyses demonstrated that activity within a network of bilateral prefrontal cortex (PFC) and posterior parietal regions was compensatory for task performance in the TBI sample. Functional connectivity analyses revealed that a common network of bilateral PFC regions was active in both groups during working memory performance, although this activity was behaviourally relevant at lower levels of task demand in TBI subjects relative to healthy controls. In study three, diffusion-imaging was used to characterize the impact of diffuse white matter pathology on these neurofunctional changes. Unexpectedly, decreased white matter integrity was not correlated with working memory performance following TBI. However, markers of white matter pathology did inversely correlate with the compensatory functional changes observed previously. These results implicate diffuse white matter pathology as a primary mechanism of functional brain change following TBI. Moreover, reactive neurofunctional changes appear to mediate the impact of diffuse injury following brain trauma, suggesting new avenues for neurorehabilitation in this population.