Biomedical subjects

Janet Bryan

Publications and source records attributed to Janet Bryan.

8 recordsLinked to original sources

PubMed2006

Ginkgo biloba: no robust effect on cognitive abilities or mood in healthy young or older adults.

Ginkgo biloba extracts are commonly used to prevent or treat memory problems but evidence on the efficacy of ginkgo is equivocal. In any case, the psychological locus of ginkgo's effects is unknown. A 12-week, double-blind, placebo-controlled study assessed effects of ginkgo (120 mg per day) on a wide range of cognitive abilities, executive function, attention and mood in 93 healthy older adults (55-79 years) and in 104 young adults (18-43 years). For the older adult sample, longer-term memory assessed by associational learning tasks showed improvement with ginkgo (d = 0.52, p = 0.04). There was no statistically significant difference on any other measure. For the young adult group no measure showed statistically significant effects of ginkgo enhancement. There were no side effects unequivocally attributable to treatment with ginkgo and those reported by participants in the ginkgo groups were mild and similar to those reported elsewhere.

Adolescent↗

PubMed2005

Effects of saccharides on brain function and cognitive performance.

This review outlines a role for saccharides in the brain and offers predictions about how saccharides might influence cognitive performance. Animal studies provide a biological mechanism by which saccharides affect brain function and, in turn, cognition. Furthermore, recent intervention studies suggest that saccharides may have an effect on the cognitive performance of humans. Because the effects of saccharide supplementation on cognitive performance are likely to be subtle, future investigations will face various methodological challenges, not the least of which is the need for sensitive outcome measures.

Animals↗

PubMed2004

Nutrients for cognitive development in school-aged children.

This review considers the research to date on the role of nutrition in cognitive development in children, with a particular emphasis on the relatively neglected post-infancy period. Undernutrition and deficiencies of iodine, iron, and folate are all important for the development of the brain and the emergent cognitive functions, and there is some evidence to suggest that zinc, vitamin B12, and omega-3 polyunsaturated fatty acids may also be important. Considerations for future research include a focus on the interactions between micronutrients and macronutrients that might be influential in the optimization of cognitive development; investigation of the impact of nutritional factors in children after infancy, with particular emphasis on effects on the developing executive functions; and selection of populations that might benefit from nutritional interventions, for example, children with nutrient deficiencies or those suffering from attention deficit-hyperactivity disorder and dyslexia.

Child↗

PubMed2003

Symptom experience in Australian men and women in midlife.

OBJECTIVE: To compare the experience of vasomotor, psychological and somatic symptoms in Australian men and women in midlife, to investigate whether symptoms often attributed to endocrine changes in midlife are associated with health and psychological well-being, and to evaluate their relationship to menopausal status in women. METHODS: A cross-sectional, correlational, population-based study based on self-report questionnaires. Participants comprised 451 men and 766 women, aged between 39 and 65, from urban and rural South Australia, who responded to invitations to participate, or who volunteered to participate following media releases. Outcome measures used comprised a 47-item symptom checklist of current presence and severity of vasomotor, somatic and psychological symptoms experienced by men and women during midlife, and measures of health and psychological well-being. RESULTS: The majority of men and women reported that they were not 'bothered' by vasomotor, psychological and somatic symptoms. For those symptoms in which men and women differed significantly, women generally reported being more 'bothered' than men, although the pattern of association between symptoms and measures of health and psychological well-being was the same for both men and women. Items from all three symptom clusters were independently related to menopausal status. CONCLUSIONS: Health and psychological well-being play a role in the genesis of symptoms experienced by men and women in midlife. Both men and women experience similar symptoms, although women are more distressed by them signifying support for a menopausal syndrome in women. The finding of an independent relationship between menopausal status and psychological and somatic symptoms, in addition to the vasomotor symptoms, contradicts the narrow-estrogen hypothesis of climacteric symptoms.

Adaptation, Psychological↗

PubMed2003

The effect of self-initiated weight-loss dieting on working memory: the role of preoccupying cognitions.

This study investigated the effects of weight loss dieting on the components of working memory and the extent to which these effects were mediated by preoccupying cognitions concerning food, diet and body shape. A dual task paradigm was used in which dieters (n=20) and non-dieters (n=20) completed mental arithmetic problems concurrently with suppression tasks designed to engage the central executive, phonological loop, and visuo-spatial sketchpad components of working memory. In addition, tasks reflecting the articulatory control process and phonological store sub-components of the phonological loop were also completed. Results showed that dieters performed more poorly on measures of the central executive and the phonological loop compared with non-dieters. Dieters reported higher levels of preoccupying cognitions which mediated the relationship between dieting status and functioning of the central executive and phonological loop, and the phonological store in particular.

Adult↗

PubMed2003

The assessment of cognitive performance in children: considerations for detecting nutritional influences.

The accurate assessment of cognitive performance in children is critical for detecting the effects of micronutrient deficiency or supplementation on the developing brain and its functions. Relatively little attention has been paid to the selection of culturally appropriate measures that are sensitive enough to detect the subtle cognitive changes that could be expected following nutritional intervention. Normal brain development and the emergence of cognitive abilities throughout infancy and childhood is discussed in this paper, followed by a description of the more pertinent and sensitive neuropsychological tests that can be used to assess cognitive performance and investigate the effects of micronutrient deficiency and supplementation on cognitive development among children in a variety of cultures.

Adolescent↗

PubMed2002

Adult age differences in strategy use during verbal fluency performance.

This study investigated adult age differences in strategy use during verbal fluency performance among 60 older and 60 younger adults. Clustering and switching, strategic components of fluency, were investigated as predictors of performance along with cognitive processes thought to underlie these strategies, namely verbal ability, speed of processing and executive function (strategic planning, performance monitoring, etc.). Two measures of verbal fluency were used: initial and excluded letter (words produced not containing a designated letter). These tasks both require search for words based on a phonemic cue but are thought to reflect a differential reliance on strategic retrieval search processes for successful performance. The number of clusters produced accounted for age differences in excluded, but not initial, letter fluency. Performance on both fluency tasks was associated with the number of clusters and switches participants produced and initial letter fluency was associated with cluster size for older adults and a ratio index of effective search for both age groups. In general, both fluency tasks relied on verbal ability and articulation speed, and excluded letter fluency performance relied more on speed and executive function than did initial letter fluency, especially for older adults.

Adolescent↗

PubMed2002

Short-term folate, vitamin B-12 or vitamin B-6 supplementation slightly affects memory performance but not mood in women of various ages.

Based on research demonstrating associations between folate, B-12 and B-6 vitamins and cognition and mood, we investigated the effects of short-term supplementation in 211 healthy younger, middle-aged and older women who took either 750 microg of folate, 15 microg of vitamin B-12, 75 mg of vitamin B-6 or a placebo daily for 35 d. In addition, we examined associations between dietary intake of these vitamins and cognition and mood. Usual dietary intake status was estimated using a retrospective, self-report, quantified food frequency questionnaire. Participants completed alternate forms of standardized tests of cognitive processing resources, memory, executive function, verbal ability and self-report mood measures before and after supplementation. Supplementation had a significant positive effect on some measures of memory performance only, and no effect on mood. Dietary intake status was associated with speed of processing, recall and recognition and verbal ability.

Adult↗