title: The effects of multiple sclerosis: Exploring executive dysfunction and its linkswith other cognitive impairment

authors: Drew, Margaret A.

abstract: Multiple Sclerosis (MS) is one of the most common chronic diseases of the central nervous system, and in New Zealand an estimated 4,000 people are currently affected. Although the physical manifestations of the disease are well known, and memory impairments have been comparatively well researched, those cognitive abilities known collectively as executive functions, and their relationship with other cognitive processes, have seldom been examined.
To fill this research gap, the present study examined the extent and nature of executive dysfunction and other cognitive impairments in a community based sample of participants with MS, and explored any links between executive dysfunction and other cognitive processes. Due to the well known heterogeneous nature of the effects of MS, impairment was assessed not only for the sample as a whole, but more informatively, and in contrast to much of the previous research on MS, within smaller more homogeneous groups formed on the basis of the extent and nature of the cognitive impairment of the participants. As the behavioural characteristics of executive dysfunction may have an influence on the ability to function appropriately on a daily basis in the community at large, evidence of typical 'dysexecutive' behaviour was also examined.
Ninety five participants with MS were assessed on general ability (WAIS-III), memory (WMS-III), executive functioning (D.KEFS), information processing speed and simple attentional processes. While the extent of impairment remained low on general ability measures, some impairment became evident in over half of the participants with MS on the memory measures. Five categories of executive functioning were used to assess the extent and nature of executive dysfunction; Inhibition, Shifting, Reasoning, Planning and Fluency. Working memory was not included as an executive category, as the primary scores obtained from the D.KEFS assessment did not enable this process to be isolated. Working memory was however evaluated as part of the memory assessment (WMS - III). Over half the participants were found to be impaired in at least one category of executive dysfunction, and the most commonly impaired categories were fluency and reasoning. Although sixteen different profiles of executive dysfunction were evident amongst the participants, the majority of those impaired were assessed with only one category of impairment. Surprisingly, no impairment in information processing speed was evident, but some participants were impaired in relation to simple attentional processes. 
The participants with MS were subsequently divided into four groups based on the nature of their impairment, that is, depending on whether the participant had no impairment, memory impairment only, memory impairment and executive dysfunction or executive dysfunction only. The index scores for visual memory were found to be consistently lower than those for auditory memory for all the 'impairment type' groups, but little difference was found between long-term and short-term memory performance. Working memory was found to be the only cognitive process which differentiated between those groups with executive dysfunction and those without, and at all levels of performance, proved to be a reliable predictor of the degree of executive dysfunction. Working memory was also found to have a differing relationship with each of the other five specific categories of executive functioning. 
When the everyday behavioural characteristics of executive dysfunction, such as inhibition, intentionality, executive memory and positive and negative affect were assessed with the Dysexecutive Questionnaire, there was little evidence of any self reported problems. In particular, levels of insight were shown not to be compromised, therefore it seemed that if any behavioural difficulties did arise for the participants, they would have been able to recognize and subsequently address them. Thus, it appeared for this sample of participants with MS that although some executive dysfunction was more prevalent than had previously been suggested in the literature on MS, generally the living arrangements of these participants seemed appropriate in relation to their ability to function independently. 
Overall, it was recommended that for the initial cognitive assessment of those with MS, a comprehensive evaluation of working memory integrity should be included. This would provide valuable information regarding the likelihood of other executive dysfunction and would allow a more targeted assessment approach by limiting the more extensive testing of executive functions to only those people whose comparatively lower working memory performance indicated that further problems may exist.

text: The effects of multiple sclerosis: Exploring executive dysfunction and its linkswith other cognitive impairment Multiple Sclerosis (MS) is one of the most common chronic diseases of the central nervous system, and in New Zealand an estimated 4,000 people are currently affected. Although the physical manifestations of the disease are well known, and memory impairments have been comparatively well researched, those cognitive abilities known collectively as executive functions, and their relationship with other cognitive processes, have seldom been examined.
To fill this research gap, the present study examined the extent and nature of executive dysfunction and other cognitive impairments in a community based sample of participants with MS, and explored any links between executive dysfunction and other cognitive processes. Due to the well known heterogeneous nature of the effects of MS, impairment was assessed not only for the sample as a whole, but more informatively, and in contrast to much of the previous research on MS, within smaller more homogeneous groups formed on the basis of the extent and nature of the cognitive impairment of the participants. As the behavioural characteristics of executive dysfunction may have an influence on the ability to function appropriately on a daily basis in the community at large, evidence of typical 'dysexecutive' behaviour was also examined.
Ninety five participants with MS were assessed on general ability (WAIS-III), memory (WMS-III), executive functioning (D.KEFS), information processing speed and simple attentional processes. While the extent of impairment remained low on general ability measures, some impairment became evident in over half of the participants with MS on the memory measures. Five categories of executive functioning were used to assess the extent and nature of executive dysfunction; Inhibition, Shifting, Reasoning, Planning and Fluency. Working memory was not included as an executive category, as the primary scores obtained from the D.KEFS assessment did not enable this process to be isolated. Working memory was however evaluated as part of the memory assessment (WMS - III). Over half the participants were found to be impaired in at least one category of executive dysfunction, and the most commonly impaired categories were fluency and reasoning. Although sixteen different profiles of executive dysfunction were evident amongst the participants, the majority of those impaired were assessed with only one category of impairment. Surprisingly, no impairment in information processing speed was evident, but some participants were impaired in relation to simple attentional processes. 
The participants with MS were subsequently divided into four groups based on the nature of their impairment, that is, depending on whether the participant had no impairment, memory impairment only, memory impairment and executive dysfunction or executive dysfunction only. The index scores for visual memory were found to be consistently lower than those for auditory memory for all the 'impairment type' groups, but little difference was found between long-term and short-term memory performance. Working memory was found to be the only cognitive process which differentiated between those groups with executive dysfunction and those without, and at all levels of performance, proved to be a reliable predictor of the degree of executive dysfunction. Working memory was also found to have a differing relationship with each of the other five specific categories of executive functioning. 
When the everyday behavioural characteristics of executive dysfunction, such as inhibition, intentionality, executive memory and positive and negative affect were assessed with the Dysexecutive Questionnaire, there was little evidence of any self reported problems. In particular, levels of insight were shown not to be compromised, therefore it seemed that if any behavioural difficulties did arise for the participants, they would have been able to recognize and subsequently address them. Thus, it appeared for this sample of participants with MS that although some executive dysfunction was more prevalent than had previously been suggested in the literature on MS, generally the living arrangements of these participants seemed appropriate in relation to their ability to function independently. 
Overall, it was recommended that for the initial cognitive assessment of those with MS, a comprehensive evaluation of working memory integrity should be included. This would provide valuable information regarding the likelihood of other executive dysfunction and would allow a more targeted assessment approach by limiting the more extensive testing of executive functions to only those people whose comparatively lower working memory performance indicated that further problems may exist.

year: 2005

title: Effects of environmental and behavioural factors on fish swimming performance and passage success

authors: Burbach Crawford, Rachel

abstract: Instream structures like culverts, dams, and other anthropogenic barriers fragment river networks worldwide, posing a significant threat to the connectivity and migration of freshwater fish communities. Designing effective fish passage solutions requires a comprehensive understanding of the swimming abilities, behaviours, and environmental tolerances of diverse fish species. This thesis aims to address this need by investigating the factors influencing the swimming performance and passage success of multiple migratory fish species in New Zealand, with implications for improving fish passage design and connectivity restoration efforts.
Two methods for assessing swimming performance, critical swimming speed (Ucrit) and sprint swimming speed (Usprint), were compared across two fish species. Results revealed no significant statistical difference between swimming speeds estimated using Ucrit versus Usprint protocols for the pelagic Galaxias maculatus and the benthic-associated Galaxias fasciatus. This suggests that shorter time-stepped swimming speeds tests can be used to measure swimming abilities of benthic-associated species, allowing comparisons across a broader range of fish for passage design.
Inter- and intraspecies variation in swimming speeds across nine migratory New Zealand fish species was quantified. Galaxias brevipinnis, Galaxias argenteus, and Galaxias postvectis exhibited the strongest swimming abilities. Galaxias maculatus was among the weakest swimmers. Body length was positively correlated with maximum speed, indicating that barriers select against weaker swimming species and smaller individuals within species. Maximum allowable culvert velocities should be significantly lower than previous standards to accommodate most individuals across species.
The impact of varying acute water temperatures on critical swimming speeds of four migratory species was investigated. At higher temperatures (26°C), three species (Galaxias maculatus, Galaxias brevipinnis, Gobiomorphus cotidianus) exhibited significant reductions in swimming performance compared to lower temperatures (8°C, 15°C). In contrast, Galaxias fasciatus showed no water temperature-related changes. These findings underscore the importance of designing fish passages to accommodate acute temperature fluctuations, to ensure successful migration under changing environmental conditions.
Potential benefits of collective navigation were explored using the small-bodied Galaxias maculatus. Experiments with an artificial velocity barrier revealed that fish swimming in groups had faster entry and passage rates, as well as lower metabolic rates indicating reduced energy expenditure, compared to solitary individuals. These findings highlight the importance of designing fish passes to facilitate movement of gregarious species by accommodating group dynamics.
The effect of repeated exposure on passage performance through an experimental raceway with high water velocities was examined. Over five consecutive days, passage success increased significantly, suggesting a role for cognition and spatial memory in improving passage performance. However, approach and entry rates did not improve, indicating other factors like attraction flows or fish physiology may be important for locating and entering structures. 
This thesis provides insights into the factors influencing swimming performance and passage success for migratory New Zealand species. By studying variation across species in water temperature effects, group behaviour, and cognitive abilities, this research provides a comprehensive understanding to guide the development of more inclusive and effective fish passage solutions. The findings highlight the importance of accounting for many sources of variation when designing instream structures to facilitate unimpeded fish migration.

text: Effects of environmental and behavioural factors on fish swimming performance and passage success Instream structures like culverts, dams, and other anthropogenic barriers fragment river networks worldwide, posing a significant threat to the connectivity and migration of freshwater fish communities. Designing effective fish passage solutions requires a comprehensive understanding of the swimming abilities, behaviours, and environmental tolerances of diverse fish species. This thesis aims to address this need by investigating the factors influencing the swimming performance and passage success of multiple migratory fish species in New Zealand, with implications for improving fish passage design and connectivity restoration efforts.
Two methods for assessing swimming performance, critical swimming speed (Ucrit) and sprint swimming speed (Usprint), were compared across two fish species. Results revealed no significant statistical difference between swimming speeds estimated using Ucrit versus Usprint protocols for the pelagic Galaxias maculatus and the benthic-associated Galaxias fasciatus. This suggests that shorter time-stepped swimming speeds tests can be used to measure swimming abilities of benthic-associated species, allowing comparisons across a broader range of fish for passage design.
Inter- and intraspecies variation in swimming speeds across nine migratory New Zealand fish species was quantified. Galaxias brevipinnis, Galaxias argenteus, and Galaxias postvectis exhibited the strongest swimming abilities. Galaxias maculatus was among the weakest swimmers. Body length was positively correlated with maximum speed, indicating that barriers select against weaker swimming species and smaller individuals within species. Maximum allowable culvert velocities should be significantly lower than previous standards to accommodate most individuals across species.
The impact of varying acute water temperatures on critical swimming speeds of four migratory species was investigated. At higher temperatures (26°C), three species (Galaxias maculatus, Galaxias brevipinnis, Gobiomorphus cotidianus) exhibited significant reductions in swimming performance compared to lower temperatures (8°C, 15°C). In contrast, Galaxias fasciatus showed no water temperature-related changes. These findings underscore the importance of designing fish passages to accommodate acute temperature fluctuations, to ensure successful migration under changing environmental conditions.
Potential benefits of collective navigation were explored using the small-bodied Galaxias maculatus. Experiments with an artificial velocity barrier revealed that fish swimming in groups had faster entry and passage rates, as well as lower metabolic rates indicating reduced energy expenditure, compared to solitary individuals. These findings highlight the importance of designing fish passes to facilitate movement of gregarious species by accommodating group dynamics.
The effect of repeated exposure on passage performance through an experimental raceway with high water velocities was examined. Over five consecutive days, passage success increased significantly, suggesting a role for cognition and spatial memory in improving passage performance. However, approach and entry rates did not improve, indicating other factors like attraction flows or fish physiology may be important for locating and entering structures. 
This thesis provides insights into the factors influencing swimming performance and passage success for migratory New Zealand species. By studying variation across species in water temperature effects, group behaviour, and cognitive abilities, this research provides a comprehensive understanding to guide the development of more inclusive and effective fish passage solutions. The findings highlight the importance of accounting for many sources of variation when designing instream structures to facilitate unimpeded fish migration.

year: 2024

title: Māori education and principles of self-determination in the twenty-first century.

authors: O’Sullivan, Dominic

subjects: Maori

abstract: This paper argues that self-determination to the greatest extent possible is a legitimate aspiration for Maori people. It is argued that in education this requires a philosophical and policy response more focused on Maori autonomy than can be provided within the bicultural framework that has lately informed Maori relationships with other actors in the education arena. The paper considers the place of kohanga reo, kura kaupapa Maori and wananga in relation to broader Maori aspirations for self-determination and discusses proposals that these aspirations be furthered through the establishment of a Maori Education Authority. It is also argued that opportunities for self-determination in New Zealand are compromised by the government's unwillingness to alter a tightly controlled centralised education market to provide genuine Māori autonomy over what type of education might be available and to what end.

text: Māori education and principles of self-determination in the twenty-first century. This paper argues that self-determination to the greatest extent possible is a legitimate aspiration for Maori people. It is argued that in education this requires a philosophical and policy response more focused on Maori autonomy than can be provided within the bicultural framework that has lately informed Maori relationships with other actors in the education arena. The paper considers the place of kohanga reo, kura kaupapa Maori and wananga in relation to broader Maori aspirations for self-determination and discusses proposals that these aspirations be furthered through the establishment of a Maori Education Authority. It is also argued that opportunities for self-determination in New Zealand are compromised by the government's unwillingness to alter a tightly controlled centralised education market to provide genuine Māori autonomy over what type of education might be available and to what end.

year: 2001