Mild Cognitive Impairment is characterized by age-related decline in a variety of cognitive domains, including reference and working memory and olfactory function. Importantly, declining age-related mnemonic abilities is not inevitable; learning and memory deficits emerge in some people by middle-age while others remain largely cognitively-intact even at advanced chronological ages. The goal of this thesis is to establish a Fischer 344 (F344) rat model with some features of human cognitive aging which can then be utilized to undercover the neurobiological underpinnings of age-related cognitive deficits. Young (6 mo), middle-aged (11 mo), and aged (22 mo) F344 rats were behaviorally characterized in a well-established reference memory version of the Morris water maze task. Indeed, age-related impairments did occur across the lifespan. Moreover, the reference memory protocol used here was sufficiently sensitive to detect a difference in individual abilities among aged F344 rats such that approximately half of the rats performed on par with young while the other half performed outside this range, demonstrating impairment. These data mimic individual differences in declarative memory among aged humans. Subsequently, subsets of rats initially characterized on the reference memory version of the water maze were tested on either a spatial working memory water maze task or an olfactory discrimination task. Despite detecting an age-related delay-dependent decline in spatial working memory, this impairment was not correlated with spatial reference memory. In contrast, a strong and significant relationship was observed among aged rats in the odor discrimination task such that aged rats with the worst spatial reference memory were also the most impaired in their ability to discriminate odors for a food reward. Importantly, this subset of cognitively-impaired rats was not impaired on digging media discrimination problems with identical task demands, nor were they anosmic. These data are among the first to demonstrate a cross-domain cognitive deficit in a rodent model of human aging. Together, the current study both confirms the use of the naturalistic F344 rat model for the study of cognitive deficits within the context of aging and provides the most comprehensive cognitive profile of this rat population to date.

The purpose of this study was to evaluate the characteristics of vocabulary use of seven- to nine-year-old bilingual children with and without language impairment. 74 participants (37 typically developing and 37 language impaired) ranging from age 7;0 to 9;11 years were matched based on age, language dominance and when they first began speaking English. The Test of Narrative Language (TNL) was administered to the participants in English and Spanish. The three oral narratives of the English and Spanish TNL were transcribed and scored. A prototypical word list was derived from 10 high scoring students from the normative data set. Word lists from both the TD and LI participants in English and Spanish were compared to the prototypical word list. Results indicated that the participants produced more prototypical words when telling stories in English than in Spanish. TD participants also produced more prototypical words than LI participants overall. The results have implications for both assessment and intervention and add to our knowledge of word selection in bilingual children with and without LI. / text

The purpose of this study was to examine factors that relate to successful adult outcomes for 28 individuals with visual impairment ages 23-30. The primary dependent variable was current employment. Independent living and completion of postsecondary educational program were secondary, related outcome measures. A secondary goal of this research was to explore self-perceived aptitude in specific skills that are related to adult outcomes and to understand how and how well participants learned these skills.A mixed-methods design was implemented and quantitative and qualitative data were collected using a highly structured 151-item telephone survey. A series of Fisher's Exact and Mann Whitney-U tests were run to explore statistically significant relationships between variables. Past employment experience was positively related to current employment. Receipt of Social Security benefits and profound vision loss were negatively related to current employment. The longer a participant had been out of high school, the more likely he/she was to have a postsecondary educational degree.Eight essential skills were examined: daily living, college preparation, social, self-advocacy, technology, transportation management, and job seeking. Overall on a scale of 1-10, participants rated their aptitude and training in essential skills areas high. Job seeking was scored the lowest and those who had worked in the past five years rated their job seeking skills higher than those without past work experience. Adults who had completed a postsecondary educational degree rated their college preparation skills higher than those who had not completed a degree program. Those who were living independently rated their overall daily living skills higher than those who were living with a parent or parents.Qualitative data suggest that some skills, such as transportation management and technology, were taught primarily by professionals in the field of visual impairment. In contrast, daily living, social and self-advocacy skills were often learned from the support of family or friends. Many adults reported that they did not receive direct instruction in social and self-advocacy skills; instead they learned them on their own. Further empirical research is needed to understand best practices for integrating effective instruction in compensatory training and their relationship to successful adult outcomes.

Prelingually profoundly deaf children usually experience problems with language learning (Webster, 1986; Campbell, Burden & Wright, 1992). The acquisition of written language would be no problem for them if normal development of reading and writing was not dependent on spoken language (Pattison, 1986). However, such children cannot be viewed as a homogeneous group since some, the minority, do develop good linguistic skills. Group studies have identified several factors relating to language skills: hearing loss and level of loss, I.Q., intelligibility, lip-reading, use of phonology and memory capacity (Furth, 1966; Conrad, 1979; Trybus & Karchmer, 1977; Jensema, 1975; Baddeley, Papagno & Vallar, 1988; Baddeley & Wilson, 1988; Hanson, 1989; Lake, 1980; Daneman & Carpenter,1980). These various factors appear to be interrelated, with phonological awareness being implicated in most. So to understand behaviour, measures of all these factors must be obtained. The present study aimed to achieve this whilst investigating the prediction that performance success may be due to better use of phonological information. Because linguistic success for the deaf child is exceptional, a case study approach was taken to avoid obscuring subtle differences in performance. Subjects were screened to meet 6 research criteria: profound prelingual deafness, no other known handicap, English the first language in the home, at least average non-verbal IQ , reading age 7-9 years and inter-subject dissimilarities between chronological reading age discrepancies. Case histories were obtained from school records and home interviews. Six subjects with diverse linguistic skills were selected, four of which undertook all tests. Phonological awareness and development was assessed across several variables: immediate memory span, intelligibility, spelling, rhyme judgement, speech discrimination and production. There was considerable inter-subject performance difference. One boy's speech production was singled out for a more detailed analysis. Useful aided hearing and consistent contrastive speech appear to be implicated in other English language skills. It was concluded that for phonological awareness to develop, the deaf child must receive useful inputs from as many media as possible (e.g., vision, audition, articulation, sign and orthography). When input is biassed toward the more reliable modalities of audition and articulation, there is a greater possibility of a robust and useful phonology being derived and thus better access to the English language.

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This study examined the effectiveness of the Otago screening protocol in identifying school-aged children with severe speech and language impairments. In order to do so, the results of the Otago screening protocol were compared with those of comprehensive language assessment as determined by best practice protocol (Gillon & Schwarz, 1998, Kennedy, 2002). Following the completion of the screening and the comprehensive assessments, an evaluation of the true positives and false positives was calculated, and an analysis of the false negative outcomes made. Findings indicated that fourteen of the twenty participants were true positives, three were true negatives, three were false positives, and none were false negatives. The Positive Predictive Value and Negative Predictive Value of the screening protocol was 100%. Test Sensitivity and Specificity were very high at 82% and 100%. Inter-rater reliability was very high, generally ranging from 92-100%. Adding a standardised measure of phonological awareness would improve efficiency of the screening protocol. Consideration of alternative screening tools, such as the GAPS test (Gardner et al, 2006) and the CELF-4 screening test (Semel, Secord & Wiig, 2004), should be made. Additional factors which could influence a screening protocol are discussed. The Otago screening protocol is a valid procedure to detect severe speech and language impairments in school-aged students referred to Special Education.

The following study describes an investigation into the impact of a life review intervention on individuals experiencing cognitive impairment who were living in care homes. Previous research into the effect of life review and reminiscence has been inconclusive. Various studies have found improvements in depression, selfesteem, and life satisfaction in individuals without cognitive impairment who have participated in these activities. Relatively little research has been carried out with people with cognitive impairment. Seventeen individuals took part in the study and were randomly allocated to one of two groups. Eight individuals entered the experimental group and participated in a structured, individual, life review intervention that culminated in the creation of a life story book. Nine individuals entered a no treatment control group and took part in the pre, post and follow up assessments only. Using four psychometric assessment scales, the two groups were compared on levels of depression, selfesteem, life satisfaction and autobiographical memory prior to, immediately after and at six weeks following completion of the life review. The quantitative results indicated a statistically significant improvement in the experimental group in depression and also in a particular aspect of autobiographical memory relating to the recall of personal factual information. Life satisfaction and self-esteem remained relatively stable throughout the study. Various limitations and strengths of the project anfl intervention model are discussed, as are a number of issues to consider when car7ing out this form of intervention with this population.

M.A. / The aim of the present study was to establish the existence of potential cognitive impairment in a group of 14 currently using methamphetamine addicts in comparison to a group of 17 abstinent recovering methamphetamine addicts and a matched control group of 18 participants. The current study was undertaken as methamphetamine abuse has risen dramatically over the past several years (Hart, Ward, Haney, Foltin & Fischman, 2001). This resurgence into popular culture imposes a sense of urgency for understanding the effects of methamphetamine medically and neurologically (Simon et al., 2000; Volkow et al., 2001a). Twenty nine million people consumed amphetamine-type stimulants in the late 1990s, a larger number than that of people using cocaine and opiates combined (World Health Organisation, 2001). South Africa is one of the countries world-wide that is currently experiencing a methamphetamine pandemic. The startling increase of methamphetamine use in South Africa is further exacerbated by the fact that 80 percent of methamphetamine users in the Western Cape are under 21 years of age, according to the South African National Council on Alcoholism and Drug Dependence (SANCA) (Morris & Parry, 2006). Methamphetamine has been established as neurotoxic in chronic doses abused by humans. The resultant deleterious consequences of this drug on cognitive functioning have led researchers to conclude that the observed deficits are as a direct result of methamphetamine’s neurotoxicity (Nordahl, Salo & Leamon, 2003; Vocci & Appel, 2007; Yucel, Lubman, Solowij & Brewer, 2007). Amongst the cognitive functions affected by methamphetamine, preliminary findings indicate that attention, memory and executive functioning may potentially be compromised (Barr et al., 2006). These findings need to be corroborated in the South African milieu using culture fair measuring instruments. Furthermore the possible effects of previous use of methamphetamine in recovering addicts need to be ascertained. A comparative and quantitative ex post facto research design was utilised in the research. Participants were selected according to stringent inclusion and exclusion criteria. A neuropsychological test battery, comprising of pen and pencil tests, was used to assess the cognitive functions of attention, memory and executive functioning in the two experimental groups and the control participants. Statistical analysis was performed on the raw data by the Statistical Consultation Service of the University of Johannesburg. The research was conducted according to a specified code of ethics stipulated for psychological research. Significant results were established between the two experimental groups in comparison to each other and the control group for the cognitive functions of attention and memory. Assessment of executive functioning yielded results in which significant results were observed between the current and recovering users of methamphetamine and between the control group and recovering methamphetamine addicts. There were no significant results detected between the current users of methamphetamine and the control group regarding executive functioning.