This thesis consisted of experiments designed to explore the construct of attention and investigate the disruptive effects of psychotomimetics, with a specific focus on NMDA antagonists. Phencyclidine (PCP) was administered through a variety of treatment regimens in order to to determine the ability of inducing cognitive-specific disruptions in attentional functioning. The hypothesis that sub-chronic exposure to PCP would result in persistent attentional impairment was tested, using the 5-choice serial reaction time task (5-CSRTT). The 5-CSRTT assesses not only visuospatial attention, but also components of impulsivity, compulsivity, speed of processing and motivation. It was determined that an additional task-related intervention that increased the attentional load was required to elucidate attentional impairment following sub-chronic PCP treatment. The ability of rats to perform the modified version of the 5-CSRTT, known as the 5-choice continuous performance test (5C-CPT), was investigated. The 5C-CPT was implemented to provide a task that may have greater analogy to the human CPT, than the original 5-CSRTT. The consequence of dopaminergic D1 system activation was investigated. It was revealed that D1 partial agonism improved attentional performance in a baseline-dependent manner. Following successful acquisition of the task, it was shown that repeated PCP treatment induced cognitive disruption that was cognitive-specific, and not confounded by generalised response disruption. Furthermore, a partial attenuation of the PCP-induced performance disruption was achieved following administration of the D1 partial agonist, SKF 38393. Moreover, sub-chronic PCP treatment was shown to impair 5C-CPT performance in the drug-free state. However, an additional challenge that further increased the attentional load was needed to elucidate a performance deficit. This highlighted that sustained attention/vigilance is sensitive to persistent impairment following sub-chronic PCP administration in a manner consistent with deficits observed in schizophrenia patients. This prompted the investigation that tested the hypothesis that sub-chronic PCP treatment could induce enduring structural deficits in regions associated with attentional performance. Magnetic resonance imaging (MRI) was conducted, in conjunction with 5-CSRTT and pre-pulse inhibition (PPI). It was revealed that sub-chronic PCP treatment resulted in morphological brain abnormalities in brain regions associated with 5-CSRTT performance. This was coupled with deficits in sustained attentional performance following an increase in attentional load, yet PPI was unaffected. Taken together, these findings suggested sub-chronic PCP treatment impairs attentional functionality, an effect that dissociates between effortful and passive attentional processes.

Please read the abstract in the section 00front of this document / Thesis (DPhil (Communication Pathology))--University of Pretoria, 2006. / Speech-Language Pathology and Audiology / DPhil / Unrestricted

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This thesis consisted of experiments designed to explore the construct of attention and investigate the disruptive effects of psychotomimetics, with a specific focus on NMDA antagonists. Phencyclidine (PCP) was administered through a variety of treatment regimens in order to to determine the ability of inducing cognitive-specific disruptions in attentional functioning. The hypothesis that sub-chronic exposure to PCP would result in persistent attentional impairment was tested, using the 5-choice serial reaction time task (5-CSRTT). The 5-CSRTT assesses not only visuospatial attention, but also components of impulsivity, compulsivity, speed of processing and motivation. It was determined that an additional task-related intervention that increased the attentional load was required to elucidate attentional impairment following sub-chronic PCP treatment. The ability of rats to perform the modified version of the 5-CSRTT, known as the 5-choice continuous performance test (5C-CPT), was investigated. The 5C-CPT was implemented to provide a task that may have greater analogy to the human CPT, than the original 5-CSRTT. The consequence of dopaminergic D1 system activation was investigated. It was revealed that D1 partial agonism improved attentional performance in a baseline-dependent manner. Following successful acquisition of the task, it was shown that repeated PCP treatment induced cognitive disruption that was cognitive-specific, and not confounded by generalised response disruption. Furthermore, a partial attenuation of the PCP-induced performance disruption was achieved following administration of the D1 partial agonist, SKF 38393. Moreover, sub-chronic PCP treatment was shown to impair 5C-CPT performance in the drug-free state. However, an additional challenge that further increased the attentional load was needed to elucidate a performance deficit. This highlighted that sustained attention/vigilance is sensitive to persistent impairment following sub-chronic PCP administration in a manner consistent with deficits observed in schizophrenia patients. This prompted the investigation that tested the hypothesis that sub-chronic PCP treatment could induce enduring structural deficits in regions associated with attentional performance. Magnetic resonance imaging (MRI) was conducted, in conjunction with 5-CSRTT and pre-pulse inhibition (PPI). It was revealed that sub-chronic PCP treatment resulted in morphological brain abnormalities in brain regions associated with 5-CSRTT performance. This was coupled with deficits in sustained attentional performance following an increase in attentional load, yet PPI was unaffected. Taken together, these findings suggested sub-chronic PCP treatment impairs attentional functionality, an effect that dissociates between effortful and passive attentional processes.

In today’s dynamic global environment, organizations need to be agile and adaptive by practicing innovative strategies in order to sustain and remain competitive. One indicator of organizational sustainability is its productivity, which translates into the productivity and performance of employees in the organization. Performance evaluation of employees is an important step in measuring the employee productivity. Such evaluations are in general conducted annually using a performance appraisal system (PAS). The annual appraisal using PAS has two major drawbacks. The first drawback is the long frequency of the appraisal process. As it is an annual affair, the errors such as subjectivity, recency error, bias, halo effect, stereotyping etc. creeps in, and as a result the evaluations will not be proper. The second drawback is with respect to fixation of target/goal achievement. While achieving the targets/goals which are fixed at the beginning of the appraisal period are important, any steps towards achieving such goals are equally important. These drawbacks can be addressed to an extent by having an ongoing or continuous method for performance evaluation of employees. Hence there is a need for continuous performance evaluation of employees (CPEE). Although the importance of CPEE has been highlighted in the literature, we are not aware of any process by which CPEE could be operationalized. In order to implement and sustain, any organizational process, it should produce certain periodic outputs, which is meaningful to its administrators and beneficiaries. In the case of CPEE one such output could be to provide a proper and timely rewards and recognition (R&R). R&R is a motivational tool used for appreciation which could boost employee performance and productivity. Research underline that R&R is strongly and positively correlated to the performance of employees. As defined in thesis, Reward is the materialistic part of the appreciation (such as memento, certificate etc.), while Recognition is the feeling of being appreciated (such as a pat on the back or a public applause). Both Reward and Recognition is considered in unison and considered as mutually inclusive in this thesis. There is some variation of R&R practiced in organizations, known as employee awards. Such awards are motivating enough for the employees. In general, the employee awards are based on nominations from the managers, which are scrutinized by an individual committee and one among the nominated employees is offered the award. Nevertheless employees are often clueless about what performance fetched them the award. In other words the criteria for such awards are often unknown. Similar to PAS, the criteria for such evaluations are developed mostly by the employers with hardly any input from the employees. Additionally the employee awards are heavily dependent upon the PAS and it is mostly an annual affair. Hence the drawbacks for PAS are also applicable for the existing employee awards process. In order to address these drawbacks, R&R should be given in an ongoing and continuous manner. Although the importance and the positive correlation between R&R and employee performance has been established, it has not known to be widely practiced in organizations. This could be due to a lack of proper framework to implement such programs. The CPEE process could be the basis for providing R&R. Therefore this thesis is aimed at developing a comprehensive framework for CPEE to offer R&R. Performance of employee is a sum total of the performances across various dimensions (such as knowledge, skills, attitudes and behaviours). As the performance for employees is a multi-dimensional concept, the criteria for evaluation using CPEE process should also be based on multiple criteria. Therefore in order to effectively address the operational process of CPEE to offer R&R, a multi-criteria decision making (MCDM) method based model needs to be developed. A focused review of the existing literature on performance evaluation of employees substantiated the research problem that there is a lack of proper framework for CPEE to offer R&R. In order to address this research problem, the main objective of this thesis is to develop a comprehensive, formal and objective method to evaluate the employee performance in a continuous manner based on multiple evaluation criteria from the perspectives of employees as well as employers to offer proper and timely reward and recognition to the best performing employee(s). In order to address the main objective of the research, the following objectives are envisaged: 1. To identify the set of variables/criteria with respect to both employees’ and employers’ perspectives and to propose an initial framework for CPEE to offer R&R. 2. To develop a final framework for CPEE to offer R&R based on the initial proposed framework and descriptive research 3 To develop a multi-criteria-decision-making (MCDM) method for the proposed framework for CPEE to offer R&R The scope of this research is limited to Information Technology (IT) organizations due to the alarming rate of attrition and the presence of younger population who are knowledge workers. They expect frequent appreciation and continuous feedback regarding their performance. In this thesis, employees are represented by Software Engineers (SEs) and the employers are represented by Project Managers (PMs). Research Objective 1: In order to address the first research objective a six phased approach is planned. In the first phase, the available literature on existing performance evaluations in general and employee motivations are reviewed to identify the possible variables/criteria for CPEE to offer R&R. This resulted in 51 variables for performance evaluation. As it cannot be confidently asserted whether these variables are applicable to employees of IT organizations, a set of unstructured interviews are conducted with Software Engineers to prepare Case-lets. This Case-let approach with Software Engineers is carried out in the second phase and 7 Case-let reports are prepared. From the analysis of the 7 Case-let reports, 27 variables are identified. As the variables identified from Case-let approach may not represent the entire IT employees, a series of semi structured interviews are conducted among 58 Software Engineers in the third phase to identify further variables/criteria and accordingly 35 variables are identified. In order to obtain the list of variables/criteria based on employers’ perspectives and to validate the set of variables/criteria suggested by Software Engineers, 31 Project Managers are interviewed following semi structured interview method in the fourth phase and 33 variables are identified. In the fifth phase, the variables identified from second to fourth phases are triangulated with those identified from literature (i.e. first phase) which resulted in 33 unique variables that could be used for CPEE of Software Engineers to offer R&R. The final set of 33 variables/criteria are appropriately grouped into variables relating to Demographic Characteristics of Software Engineers (DCSE) and Performance of Software Engineers (PSE). Accordingly, 5 variables related to DCSE and 28 variables related to PSE out of the 33 variables finalized for CPEE to offer R&R, are grouped. Utilizing these grouped sets of variables in DCSE and PSE, an initial framework for CPEE to offer R&R is proposed in the sixth phase. Research Objective 2: In order to validate and to statistically finalize the proposed initial framework, a descriptive research is conducted. For this the importance of each of the identified 33 variables are sought from 443 Software Engineers from 12 IT organizations. A bivariate analysis is planned to analyse the significance of variables of DCSE with the variables of PSE. As there are 28 variables in PSE, they are further grouped with respect to the latent structure using a factor analysis. The factor analysis yielded six factors for measuring PSE. The factors (called as main criteria) are Proactive, Prompt, Resourceful, Responsible, Diagnostic and Dynamic. Based on the bivariate analysis among variables in DCSE and the six main criteria, only three variables, out of five variables of DCSE emerged as significant. Based on the factor analysis and bivariate analysis, the proposed initial framework is modified. Appropriate hypotheses are proposed to indicate the relation between DCSE, PSE and R&R in the modified framework. The modified framework is validated by developing suitable Structural Equation Model (SEM) to verify the hypotheses. The relative influence of DCSE, PSE and R&R are identified based on statistical validation and the framework is finalized. Research Objective 3: As there are six main criteria identified in PSE for CPEE to offer R&R, the proposed framework could be appropriately modelled using MCDM method(s)/models(s). As CPEE is a continuous process, the performance evaluation using CPEE should take only a minimum time for completion of evaluation process, and it should be easy to implement and administer and also should be flexible to accommodate any changes in the criteria or alternatives. These are the preconditions to select the suitable MCDM method(s)/model(s) to operationalize the process of CPEE to offer R&R. In order to select a suitable MCDM method from the available methods, various MCDM methods are screened based on the expected preconditions of the framework. Pugh Matrix Method (PMM) is selected for the CPEE process and is modified to address the basic drawbacks of PMM so as to utilize in this thesis. Accordingly, the MCDM methods: AHP and a Modified Pugh Matrix Method (MPMM) (which are meeting the expected preconditions of the framework such as minimum time, maximum easiness and maximum flexibility) are considered to model the proposed framework for CPEE to offer R&R. The AHP is used to calculate the relative weights and the MPMM is used to compare the performance of employees to provide a relative score. Accordingly, the proposed MCDM based modelling framework for CPEE to offer R&R is demonstrated by developing a suitable example. The MCDM method for CPEE to offer R&R developed in this thesis provides a performance score for every employee for every performance-cycle of CPEE. This score could be stored in a database which could be appropriately utilized during the periodic performance appraisal process using PAS. Overall, the contributions of the research are: (i) a new research problem on CPEE to offer R&R is identified (ii) a set of variables/criteria are identified from both employees and employers perspective, particularly for IT Organizations and an initial framework for CPEE to offer R&R is proposed (iii) a statistically finalized framework for CPEE to offer R&R is presented with the variables/ criteria identified (iv) simple MCDM methods are developed for the operationalization of the proposed framework for CPEE to offer R&R and a possible integration with the organization’s existing PAS is also conceptually presented. (ii) Although the research has accomplished its objectives, there are certain limitations such as (i) the focus of research is limited only to IT organizations, and hence cannot necessarily be generalized, the sampling is based on convenience and assumed to represent the entire IT population in the country and (iii) other MCDM methods are not explored so as to develop the proposed framework. Addressing these could be some of the future research directions in this area.

La maladie de Parkinson (MP) est la deuxième affection neurodégénérative la plus fréquente après la maladie d’Alzheimer. Elle se caractérise par un dysfonctionnement du système des ganglions de la base, en rapport avec une dégénérescence des neurones dopaminergiques de la substance noire compacte. A côté des symptômes moteurs, la MP s’accompagne de troubles cognitifs, en particulier une altération des capacités de sélectivité attentionnelle. Ce déficit attentionnel se traduit par des difficultés à sélectionner les informations pertinentes pour la conduite en cours et peut entraîner des troubles cognitifs légers. L’origine des troubles attentionnels reste imprécise : on ignore s'ils résultent d’une défaillance des mécanismes volontaires d’orientation de l’attention ou d'une perturbation des processus automatiques de capture attentionnelle. Le filtrage sensoriel permet de focaliser notre attention grâce à une sélection des informations pertinentes pour l’action en cours et une inhibition des informations non pertinentes. Il peut être exploré en neurophysiologie par le paradigme d’inhibition par le prepulse (PPI). Ce dernier correspond à l’atténuation de la réponse motrice et corticale suite à la présentation d’un stimulus sursautant (pulse) lorsque celui-ci est précédé de quelques millisecondes d’un stimulus non sursautant (prepulse). Le PPI est influencé par l’attention, son amplitude étant majorée lorsque l’attention est portée volontairement sur le prepulse. L’objectif général était donc de mieux identifier la nature des troubles de la sélectivité attentionnelle dans la MP par un paradigme actif de PPI au cours duquel la réponse corticale au pulse est enregistrée. Nous faisions l’hypothèse que les parkinsoniens présenteraient une inhibition plus faible que les témoins sains. En cas de défaillance de mobilisation volontaire des ressources attentionnelles, l'inhibition de la réponse corticale au pulse devrait être moins importante lorsque les ressources attentionnelles allouées au traitement du prepulse mettent en jeu la mobilisation volontaire de l’attention. A l’inverse, en cas de défaut de capture attentionnelle, l’inhibition de la réponse serait moins importante lorsque le traitement du prepulse implique les processus automatiques de capture.Pour répondre à cet objectif, nous avons dans un premier temps développé et validé un paradigme actif de PPI au cours duquel l’effet de la mobilisation volontaire de l’attention et de la capture attentionnelle sur le processus de filtrage sensoriel a été évalué. Pour ce faire, 26 témoins sains jeunes ont bénéficié d’un électroencéphalogramme à haute résolution tout en réalisant une tâche attentionnelle sur laquelle a été greffé un paradigme actif de PPI. Nous avons recueilli la réponse corticale évoquée et induite par la présentation du pulse. 16 témoins sains âgés, 16 patients parkinsoniens sans trouble cognitif et 16 patients avec troubles cognitifs légers ont bénéficié du même enregistrement au cours de la même tâche attentionnelle. Chez les témoins sains jeunes, nous avons montré que les processus de mobilisation volontaire de l’attention et de capture attentionnelle modulaient de façon différentielle la réponse évoquée et induite par la présentation du pulse. Au cours du vieillissement, nous avons observé une meilleure sensibilité de la réponse corticale induite, ce qui nous a conduit à choisir ce marqueur cortical pour évaluer le filtrage sensoriel dans la MP. Nos résultats montrent une réduction de l’inhibition de la réponse induite chez les parkinsoniens avec troubles cognitifs légers, confirmant la distractibilité. La MP s’accompagne aussi d’une altération dans la génération des oscillations corticales dans la bande de fréquence thêta quand la focalisation de l’attention est engagée. / Parkinson’s disease (PD) is the most frequent neurodegenerative disorder after Alzheimer’s disease. It is characterized by degeneration of dopaminergic neurons in the substantia nigra pars compacta, causing a progressive loss of dopamine neurotransmission within the basal ganglia. Apart from motor symptoms, PD patients have cognitive disorders. Namely, focused attention is impaired and PD patients fail to select task-relevant information, leading sometimes to mild cognitive impairment (MCI). The origin of this impairment is still debated: PD-related selective attention deficit may be due either to a failure of goal-directed or stimulus-driven attention. Sensory gating helps the individuals to selectively allocate their attentional resources to salient stimuli and to inhibit irrelevant information. One of the physiological marker of this process is referred to as prepulse inhibition (PPI). It corresponds to the attenuation of the motor and cortical responses to a startling stimulus (pulse) when a non-startling stimulus (the prepulse) precedes the pulse by few milliseconds. PPI can be modulated by attention, its magnitude being greater after a to-be attended prepulse. Moreover, PPI is mediated by basal ganglia.The main aim of this work was to better identify the mechanisms involved in selective attention deficits in PD. We used an active PPI paradigm and recorded the cortical response to the pulse. We assumed that PD patients would exhibit a lower inhibition of the cortical response than healthy controls. If attention deficits in PD are related to an impairment of goal-directed attention, PD patients would exhibit lower inhibition after a to-be attended prepulse than in the other conditions. At the opposite, if it is due to a failure of stimulus-driven attention, inhibition would be lower after a prepulse which involuntarily captures attention than in the other conditions.In order to reach this objective, we have first developed and validated a new active PPI paradigm in order to investigate the role of goal-directed and stimulus-driven attention on sensory-cognitive gating. To this end, high resolution electroencephalogram was recorded in 26 young healthy subjects. They performed a selective attention task combined with an active PPI paradigm and the auditory-evoked and induced cortical response to the pulse was recorded. Then, the same procedure was administered in 16 elderly healthy subjects, 16 PD patients without MCI and 16 PD patients with MCI. In young healthy subjects, we found that stimulus-driven and goal-directed attention each had specific effects on the inhibition of the evoked and induced response to the pulse. The investigation of age-related changes on sensory gating revealed that the induced cortical response was more sensitive for assessing age-related changes than the evoked response. Then, we chose this cortical marker to investigate sensory gating in PD. Our results showed that PD patients with MCI exhibit lower inhibition of induced cortical response to the pulse than healthy controls. This finding confirms previous results showing a high distractibility in these patients. Moreover, PD patients exhibit impaired theta synchronization when focused attention was engaged.

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In a rapidly changing and competitive world organisations need to develop and improve their performance continuously to ensure a competitive advantage. Organisations need to determine their current status of performance constantly and identify organisational strengths and areas where improvements can be made. Periodic organisational self-assessments are therefore required to measure current management and operations policies, practices and procedures, in order to enhance overall business performance rather than solely concentrating on the quality of products or services. Traditionally, external inspections were more commonly used by educational and training institutions for the evaluation of institution and learner performance. These institutions are today taking part in a growing drive for internal self-evaluation, arising from the desire of institutions and Education, Training and Development (ETD) practitioners to assess their own performances. Self-assessment as part of an endeavour to sustain continuous improvement is therefore also appropriate for ETD providers in the South African National Defence Force (SANDF). A new defence dispensation and a changing ETD environment in South Africa have created new demands on ETD providers in the SANDF. Although training units within the SANDF may function in a unique military context, national legislation relevant to ETD and the latest approach of openness and transparency into matters of the Department imply that military as well as non-military ETD in the SANDF is to be closely aligned with national training and development initiatives. As legislation does not make a distinction between military and private ETD providers in South Africa, most traditionally assumed differences are no longer relevant. A case study explored the appropriateness of conducting organisational self-assessment as component of a Continuous Performance Improvement Strategy and Quality Assurance within the SANDF. The study also investigated the usefulness of a Total Quality Management approach to quality assurance in the ETD environment and the impact of the frameworks used, available assessment instruments and the selected assessment methods on the significance of organisational self-assessment by ETD providers. This study's investigation of the appropriateness and significance of regular organisational self-assessments by training units in the SANDF thus has broader implications, as recommendations are also applicable to other ETD providers. / Educational Studies / D. Ed. (Education Management)

In a rapidly changing and competitive world organisations need to develop and improve their performance continuously to ensure a competitive advantage. Organisations need to determine their current status of performance constantly and identify organisational strengths and areas where improvements can be made. Periodic organisational self-assessments are therefore required to measure current management and operations policies, practices and procedures, in order to enhance overall business performance rather than solely concentrating on the quality of products or services. Traditionally, external inspections were more commonly used by educational and training institutions for the evaluation of institution and learner performance. These institutions are today taking part in a growing drive for internal self-evaluation, arising from the desire of institutions and Education, Training and Development (ETD) practitioners to assess their own performances. Self-assessment as part of an endeavour to sustain continuous improvement is therefore also appropriate for ETD providers in the South African National Defence Force (SANDF). A new defence dispensation and a changing ETD environment in South Africa have created new demands on ETD providers in the SANDF. Although training units within the SANDF may function in a unique military context, national legislation relevant to ETD and the latest approach of openness and transparency into matters of the Department imply that military as well as non-military ETD in the SANDF is to be closely aligned with national training and development initiatives. As legislation does not make a distinction between military and private ETD providers in South Africa, most traditionally assumed differences are no longer relevant. A case study explored the appropriateness of conducting organisational self-assessment as component of a Continuous Performance Improvement Strategy and Quality Assurance within the SANDF. The study also investigated the usefulness of a Total Quality Management approach to quality assurance in the ETD environment and the impact of the frameworks used, available assessment instruments and the selected assessment methods on the significance of organisational self-assessment by ETD providers. This study's investigation of the appropriateness and significance of regular organisational self-assessments by training units in the SANDF thus has broader implications, as recommendations are also applicable to other ETD providers. / Educational Studies / D. Ed. (Education Management)