How do educators in one New Zealand undergraduate Bachelor of Oral Health course teach and nurture professionalism?

INTRODUCTION: Research on integrated dental hygiene and dental therapy courses is scarce; studies reporting on how staff in these combined scope courses teach professionalism are even more scarce. This study aimed to partially fill these research gaps. METHOD AND MATERIALS: In 2016, online surveys were sent to 34 staff members who taught into the integrated Bachelor of Oral Health (BOH) course at the University of Otago's Faculty of Dentistry; 13 were returned. Two focus groups were conducted with six BOH educators. RESULTS: Aspects of professionalism were taught and nurtured in the formal curriculum, the clinic and the informal curriculum. In the formal curriculum, policies outlining the professional standards of behaviour expected of oral health practitioners and students in New Zealand and the Faculty were discussed. In the clinic, educators taught professionalism through modelling clinical skills, assessing students' performance and commenting on their reflective logbooks. In the informal curriculum, BOH teachers nurtured professionalism through discussions about standards of behaviour outside of the university. Role modelling was the most common method that participants reported they taught or nurtured professionalism in their students. DISCUSSION: Professionalism is a complex concept that is taught and nurtured in a number of ways over all aspects of the course. CONCLUSION: Oral Health educators need to maintain a high standard of professionalism when interacting with students and patients, as well as in public spaces, in order to model professionalism to their students.

Resin Infiltration of Caries in Primary Molars in a Community Setting: 24-Month Randomized Controlled Trial Findings.

This study aimed to assess whether resin infiltration of primary molar proximal lesions is more effective than noninvasive measures in radiographically controlling carious lesion progression into the dentin. A split-mouth randomized controlled trial included 90 children, each with 2 proximal lesions confined to the inner half of the enamel or ≤0.5 mm into the dentin. For each child, lesions were randomly allocated to test (infiltration: DMG Icon preproduct and fluoride varnish) or control (fluoride varnish) status. The primary outcome measure was 24-mo radiographic lesion progression. Placement of a restoration during the study period was counted as lesion progression. Proportions of teeth with progressed lesions were compared using the McNemar test. Children also reported on the treatment's acceptability to them. Children (46% female) ranged in age from 6 to 9 y. Their mean number of decayed, missing, and filled teeth (d3mft) was 2.8 (SD 2.6). At baseline, 58% and 42% of children were at moderate and low risk, respectively. Test and control lesions presented with similar radiographic lesions at baseline. At the 24-mo follow-up, 6 children had moved and 30 teeth had exfoliated. In the test and control groups, 15 of 66 lesions (22.7%) and 30 of 69 lesions (43.5%) had progressed, respectively (P < 0.05). The 2-y therapeutic effect (based on pairwise radiographic readings) of infiltration over fluoride varnish was 20.8% (95% confidence interval, 10.6%-30.2%). Nearly all children (96.7%) had enjoyed their visit to the clinic, and more than two-thirds (72.2%) were not worried about returning for treatment. Infiltration is more efficacious than fluoride varnish for controlling carious lesion progression in proximal lesions in primary molars, and most children find the treatment acceptable (Australian New Zealand Clinical Trials Registry ANZCTR.org.au ACTRN12611000827932). Knowledge Transfer Statement: These study findings can help clinicians decide which caries management approach they wish to use to prevent progression of proximal lesions in primary molars. With consideration of cost and patient preference, this information could lead to more appropriate therapeutic decisions.

Changes in Bachelor of Oral Health students' perceptions of their dental education environment.

This study used the Dundee Ready Educational Environment Measure (DREEM) to examine how a cohort of Bachelor of Oral Health (BOH) students at the University of Otago's Faculty of Dentistry perceived their educational environment. Four DREEM questionnaires were administered over the three-year programme; a modified version at the beginning of the first year asked students what they expected their year would be like, while questionnaires at the end of each subsequent year surveyed students on their actual experiences within the BOH programme. All four questionnaires were completed by 78% of students (N=31). Overall, the students' perceptions of their educational environment were more positive than negative, and they identified both strengths and weaknesses in the BOH programme. Both positive and negative shifts occurred between the 'Expected' and 'Actual' individual DREEM outcomes. The difference between students' 'Expected' and 'Actual' DREEM responses indicates, in some areas, that BOH students expected more from their educational environment than what they actually experienced. The changes in BOH students' perception of their educational environment over the three years can be explained, in part, by changes in the curriculum from year to year.

The bone morphogenetic protein receptor-1A pathway is required for lactogenic differentiation of mammary epithelial cells in vitro.

Bone morphogenetic proteins (BMPs) have been implicated in the control of proliferation, tissue formation, and differentiation. BMPs regulate the biology of stem and progenitor cells and can promote cellular differentiation, depending on the cell type and context. Although the BMP pathway is known to be involved in early embryonic development of the mammary gland via mesenchymal cells, its role in later epithelial cellular differentiation has not been examined. The majority of the mammary gland development occurs post-natal, and its final functional differentiation is characterized by the emergence of alveolar cells that produce milk proteins. Here, we tested the hypothesis that bone morphogenetic protein receptor 1A (BMPR1A) function was required for mammary epithelial cell differentiation. We found that the BMPR1A-SMAD1/5/8 pathway was predominantly active in undifferentiated mammary epithelial cells, compared with differentiated cells. Reduction of BMPR1A mRNA and protein, using short hairpin RNA, resulted in a reduction of SMAD1/5/8 phosphorylation in undifferentiated cells, indicating an impact on this pathway. When the expression of the BMPR1A gene knocked down in undifferentiated cells, this also prevented beta-casein production during differentiation of the mammary epithelial cells by lactogenic hormone stimulation. Addition of Noggin, a BMP antagonist, also prevented beta-casein expression. Together, this demonstrated that BMP-BMPR1A-SMAD1/5/8 signal transduction is required for beta-casein production, a marker of alveolar cell differentiation. This evidence functionally identifies BMPR1A as a potential new regulator of mammary epithelial alveolar cell differentiation.

Attitudes of New Zealand dentists, dental specialists and dental students towards employing dual-trained Oral Health graduates.

AIMS: To determine the attitudes of New Zealand dentists and dental specialists towards employing dual-trained Oral Health (dental therapy/dental hygiene) graduates, their knowledge of the scopes of practice and practising requirements for Oral Health (OH) graduates, and the barriers to employment of these graduates. MATERIALS AND METHODS: A postal questionnaire was sent to 600 dentists randomly selected from the Dental Council of New Zealand register, as well as all dental specialists on the register. All fifth-year dental students in 2008 were also surveyed. RESULTS: The response rates for the questionnaires were 66.8% for dentists, 64.5% for dental specialists (specialists) and 72.9% for dental students. Knowledge of the scopes of practice and practising requirements for OH graduates was limited in some areas. Fifty-nine percent of private dental practitioners (PDP dentists) and 53% of specialists would consider employing an OH graduate. The main reason given for not employing an OH graduate was insufficient physical space in the practice. CONCLUSION: New Zealand dentists and dental specialists were receptive to employing OH graduates. Knowledge of the OH scopes of practice and practising requirements is likely to improve as more OH students graduate and start work. The OH graduates have the potential to make a valuable contribution to the dental team.

Characterization of mammary epithelial cell line HC11 using the NIA 15k gene array reveals potential regulators of the undifferentiated and differentiated phenotypes.

Differentiation of undifferentiated mammary epithelial stem and/or progenitor cells results in the production of luminal-ductal and myoepithelial cells in the young animal and upon pregnancy, the production of luminal alveolar cells. A few key regulators of differentiation have been identified, though it is not known yet how these proteins function together to achieve their well-orchestrated products. In an effort to identify regulators of early differentiation, we screened the NIA 15k gene array of 15,247 developmentally expressed genes using mouse mammary epithelial HC11 cells as a model of differentiation. We have confirmed a number of genes preferentially expressed in the undifferentiated cells (Lgals1, Ran, Jam-A and Bmpr1a) and in those induced to undergo differentiation (Id1, Nfkbiz, Trib1, Rps21, Ier3). Using antibodies to the proteins encoded by Lgals1, and Jam-A, we confirmed that their proteins levels were higher in the undifferentiated cells. Although the amounts of bone morphogenetic protein receptor-1A (BMPR1A) protein were present at all stages, we found the activity of its downstream signal transduction pathway, as measured by the presence of phosphorylated-SMAD1, -SMAD5, and -SMAD8, is elevated in undifferentiated cells and decreases in fully differentiated cells. This evidence supports that the BMPR1A pathway functions primarily in undifferentiated mammary epithelial cells. We have identified a number of genes, of known and unknown function, that are candidates for the maintenance of the undifferentiated phenotype and for early regulators of mammary alveolar cell differentiation.

Musculoskeletal symptoms in New Zealand dental therapists: prevalence and associated disability.

OBJECTIVE: To determine the prevalence and associations of disability due to musculoskeletal symptoms among practising New Zealand dental therapists. DESIGN: Cross-sectional survey of a random sample of dental therapists. METHOD: A postal questionnaire was sent out to all 483 registered dental therapists who were New Zealand Dental Therapists' Association (NZDTA) members in 2005. RESULTS: Usable responses were obtained from 323 therapists (98.8% female; mean age 49.2; age range 23 to 72). The most commonly reported problems in the previous year were neck (56.8%), lower back (54.0%) or shoulder symptoms (52.4%). Fewer of those working regularly with a dental assistant reported shoulder symptoms, but they had a higher prevalence of hip/thigh symptoms. Overall, the prevalence of disability ranged from approximately one in five (neck) to one in three (elbows or lower back) of those reporting symptoms. CONCLUSIONS: The prevalence of musculoskeletal symptoms among New Zealand dental therapists is high, with neck, shoulder and lower back symptoms being particularly common. The impact of those symptoms on sufferers' daily lives is considerable. Both therapists and employers need to examine ways of minimising musculoskeletal stress in order to minimise the incidence of new cases, and to support sufferers so that they are not lost prematurely from a workforce group which is already struggling to maintain sufficient practising numbers.

Early allergen exposure and atopic eczema.

BACKGROUND: The relationship between exposure to indoor aeroallergens in early life and subsequent eczema is unclear. We have previously failed to show any significant associations between early life exposure to house dust mite and cat fur allergens and either sensitization to these allergens or wheeze. We have also previously reported a lower prevalence of parent-reported, doctor-diagnosed eczema by age 2 years for children exposed to higher concentrations of house dust mite, but no other associations with other definitions of eczema or for exposure to cat allergen. OBJECTIVES: To extend the exposure-response analysis of allergen exposure and eczema outcomes measured up to age 8 years, and to investigate the role of other genetic and environmental determinants. METHODS: A total of 593 children (92 x 4% of those eligible) born to all newly pregnant women attending one of three general practitioner surgeries in Ashford, Kent, were followed from birth to age 8 years. Concentrations of house dust mite and cat allergen were measured in dust samples collected from the home at 8 weeks after birth. The risk of subsequent eczema as defined by the U.K. diagnostic criteria was determined according to different levels (quintiles) of allergen exposure at birth. RESULTS: By age 8 years, 150 (25 x 3%) children had met the diagnostic criteria for eczema at least once. Visible flexural dermatitis was recorded at least once for 129 (28 x 0%). As in other studies, parental allergic history was positively associated with most eczema outcomes, as were higher maternal education and less crowded homes. No clear linear associations between early exposure to house dust mite or cat allergen were found, regardless of the definition of eczema used. The risk of eczema appeared to increase for the three lowest quintiles of house dust mite allergen exposure (odds ratio, OR 1 x 37 for third quintile compared with first), and then to fall for the two highest quintiles (OR 0 x 66 and 0 x 71) even after controlling for confounding factors. CONCLUSIONS: The lack of any clear exposure-disease relationship between allergens in early life and subsequent eczema argues against allergen exposure being a major factor causing eczema. If the lower levels of eczema at higher levels of house dust mite are confirmed, then interventions aimed at reducing house dust mite in early infancy could paradoxically increase the risk of subsequent eczema.

Increasing testosterone levels and effects on cognitive functions in elderly men and women: a review.

Low testosterone (T) levels may predispose to Alzheimer disease (AD), but it is unclear whether this is a co-morbid effect due to cachexia, subclinical hyperthyroidism or other co-morbidity. The biological plausibility for potential protective effects of T on brain functions is substantial. In addition, higher levels of gonadotropins found in older cases with AD suggest that low levels of T are not due to brain degeneration and that the hypothalamic-pituitary-gonadal (HPG) axis is still intact. Men genetically at risk for AD were also already found to have lower levels of T. However, despite having lower levels of T, women do not show accelerated cognitive decline with age when compared to men. In addition, castration has not necessarily shown a decline in cognitive functions; some studies even found improvement of memory recall. Age may be an important factor when assessing optimal levels of T and several studies suggest that free or bioavailable T may be a better marker than total T levels when investigating associations of androgen activity with cognitive function. Small-scale T intervention trials in elderly men with and without dementia suggest that some cognitive deficits may be reversed, at least in part, by short term T supplementation. Age and prior hypogonadism may play an important role in therapy success and these factors should be investigated in more detail in future large scale randomized controlled studies. For elderly women, T treatment does not seem to have additional benefits over estrogen treatment for postmenopausal complaints and cognitive decline and may increase cardiovascular disease.

Early allergen exposure, skin prick responses, and atopic wheeze at age 5 in English children: a cohort study.

BACKGROUND: For many years it has been assumed that the risk of childhood respiratory allergies is related to allergen exposures in early life. There are, however, few prospective data in support. We aimed to examine this relationship in a representative cohort of children born in Ashford, Kent (UK). METHODS: 625 children (94% of those eligible) were followed from birth to the age of 5.5 years at which time 552 underwent skin prick testing to extracts of house dust mite and cat fur allergens. Maternal reports of wheeze in the last year were collected by interview. These outcomes were related to individual domestic concentrations of Der p 1 and Fel d I allergens estimated from dust collection at the age of 8 weeks. RESULTS: 10% of children were sensitised to house dust mite or cat at age 5.5 years; 7% had atopic wheeze. No significant relationships between allergen exposure and either sensitisation or wheeze were found but, on examination, the exposure-response relationships for both allergens and for each outcome rose steeply at low levels of exposure and were attenuated at high levels of exposure. These patterns were modified by paternal atopy and by birth order. CONCLUSIONS: There are no linear relationships between early allergen exposure and the induction of childhood respiratory allergy; rather, the risks of IgE sensitisation and asthma rise at very low levels of exposure and are attenuated thereafter. These patterns are influenced by parental atopy and birth order. These findings suggest important gene-environment interactions in the development of atopy and asthma and imply that reductions in domestic allergen exposure alone are unlikely to have a major impact in decreasing the incidence of these diseases in childhood.

New pregnancies and loss of allergy.

BACKGROUND: Inverse associations between allergic disease and sibship have been consistently described and are frequently explained by purported lower rates of early infection among children from small families. Alternative explanations include the possibility that pregnancy itself determines maternal atopic status. OBJECTIVE: To test the hypothesis that atopy defined by skin prick test (SPT) declines with increasing numbers of pregnancies. METHODS: At enrollment to a birth cohort, mothers were skin prick tested to three common allergens. Seven years later these women underwent a second SPT and provided information on their reproductive histories. At both visits, information on allergic disease was also sought. RESULTS: Twenty five (15%) women who were initially atopic were no longer so at the second visit; loss of hayfever symptoms was reported by 33 (29%) women. Women with higher numbers of intervening pregnancies were more likely to 'lose' their atopy (P=0.05) and symptoms of hayfever (P=0.02); this was not true for asthma. The findings could not be accounted for by maternal age. CONCLUSION: Successive pregnancies may in part determine a mother's atopic state. Since maternal atopy is a risk factor for childhood atopic disease, this process may affect the atopic state of successive children. These findings suggest an alternative explanation for the sibship effect in allergic disease.

Free testosterone and risk for Alzheimer disease in older men.

OBJECTIVE: To investigate the relationships between age-associated decreases in endogenous serum total testosterone (T) and a free T index (FTI) in men and the subsequent development of Alzheimer disease (AD). METHOD: The authors used a prospective, longitudinal design with follow-up in men since 1958. Participants were from the Baltimore Longitudinal Study of Aging, a community-dwelling volunteer sample with baseline ages of 32 to 87 years. All subjects were free of AD at baseline T assessment. Five hundred seventy-four men assessed at multiple time points were followed for a mean of 19.1 years (range, 4 to 37 years). Diagnoses of AD were based on biennial physical, neurologic, and neuropsychological evaluations. RESULTS: Diagnosis of AD was associated inversely with FTI by itself and after adjustments for age, education, smoking status, body mass index, diabetes, any cancer diagnoses, and hormone supplements. In separate analyses, total T and sex hormone binding globulin were not significant predictors after adjustment with covariates. Increases in the FTI were associated with decreased risk of AD (hazard ratio = 0.74; 95% CI = 0.57 to 0.96), a 26% decrease for each 10-nmol/nmol FTI increase. CONCLUSIONS: Calculated free testosterone concentrations were lower in men who developed Alzheimer disease, and this difference occurred before diagnosis. Future research may determine whether higher endogenous free testosterone levels offer protection against a diagnosis of Alzheimer disease in older men.

Early prescriptions of antibiotics and the risk of allergic disease in adults: a cohort study.

BACKGROUND: It is frequently asserted that antibiotic prescriptions in childhood are associated with the development of allergic disease, especially asthma. A study was undertaken to establish the direction of this relationship. METHODS: A retrospective cohort study of 746 adults was performed in three general practices. Antibiotic prescriptions in the first 5 years of life, collected from contemporary medical records, were related to self-reports of asthma and hay fever and the results of skin prick testing with common aeroallergens. RESULTS: There was no relationship between early antibiotic prescription and atopy, either for all antibiotic use (OR 1.01) or for antibiotics prescribed at different ages. The significant associations between prescriptions at ages 4 and 5 and hay fever (OR 1.23 and 1.16, respectively) were explained by coexisting asthma. Relationships between antibiotic use and asthma (allergic or otherwise) were statistically significant and strengthened with increasing age of prescription, but were largely confined to antibiotics prescribed for lower respiratory symptoms. CONCLUSIONS: The reported associations between childhood antibiotic use and asthma are most plausibly explained by "reverse causation"--the tendency for prescriptions to be written for the early manifestations of pre-existing asthma.

Can early infection explain the sibling effect in adult atopy?

Atopy is strongly and inversely related to family size, a pattern which is plausibly assumed to reflect a protective effect of early infection. The current study tested this hypothesis by case-referent analysis of an adult cohort in the UK. The study established that atopy, defined by prick tests to common aeroallergens, was less common among those from larger families after adjustment for potentially confounding factors. In particular, a higher number of brothers appeared to offer protection. The current authors attempted to explain this distribution by examining contemporary family-doctor records of early childhood infections; and by a number of other indirect indices of early-life "hygiene". The sibling effect was unexplained by evidence of infection with either hepatitis A or Helicobacter pylori, or by counts of infections or antibiotic prescriptions in early life. There was a significant and independent negative association between the number of gastrointestinal infections before the age of 5 yrs and the odds of atopy. Dog ownership and home moving in early life also displayed potentially protective associations. Although the current study replicates the finding that atopy is inversely associated with family size this could not be explained by documentary or serological evidence of early infection. The findings support the suggestion that the "sibling effect" in atopy may not simply reflect protection by early infection.

Age differences in spatial memory in a virtual environment navigation task.

The use of virtual environment (VE) technology to assess spatial navigation in humans has become increasingly common and provides an opportunity to quantify age-related deficits in human spatial navigation and promote a comparative approach to the neuroscience of cognitive aging. The purpose of the present study was to assess age differences in navigational behavior in a VE and to examine the relationship between this navigational measure and other more traditional measures of cognitive aging. Following pre-training, participants were confronted with a VE spatial learning task and completed a battery of cognitive tests. The VE consisted of a richly textured series of interconnected hallways, some leading to dead ends and others leading to a designated goal location in the environment. Compared to younger participants, older volunteers took longer to solve each trial, traversed a longer distance, and made significantly more spatial memory errors. After 5 learning trials, 86% of young and 24% of elderly volunteers were able to locate the goal without error. Performance on the VE navigation task was positively correlated with measures of mental rotation and verbal and visual memory.

Environmental associations with eczema in early life.

BACKGROUND: Although atopic eczema (AE) is a common disease, little is known about its causes. OBJECTIVES: To investigate the role of dietary and environmental factors associated with the development of AE by the age of 2 years. METHODS: A cohort of children was recruited before birth from a consecutive series of newly pregnant mothers presenting for antenatal care at three general practices in Ashford, Kent, U.K. Data up to the age of 2 years were available for 624 (97%) of the original cohort. AE was defined using components of the U.K. diagnostic criteria for AE, maternal report of doctor-diagnosed eczema and maternally reported eczema. Exposures of interest were family history of allergic disease, dietary and breastfeeding patterns, family size and exposure to indoor domestic allergens. RESULTS: The cumulative prevalence of AE using the U.K. diagnostic criteria was 14% (95% confidence interval, CI 11-17%). The prevalence of maternally reported doctor-diagnosed eczema was much higher (31%, 95% CI 27-35%) and almost half (45%) the mothers reported that their child had ever had eczema (95% CI 41-49%). The relationship between parental atopy, parental history of allergic disease and the child's eczema was consistently stronger for the mothers than the fathers. There was a marked increase in the prevalence of eczema with increasing maternal education and in less crowded homes, associations that remained significant after controlling for other factors. CONCLUSIONS: The associations with environmental factors are consistent with the hypothesis that more crowded houses, increased family size and birth order, which may possibly increase early exposure to infections, may offer protection from subsequent development of eczema.

Callosal atrophy correlates with temporal lobe volume and mental status in Alzheimer's disease.

BACKGROUND: Recent studies have reported significant atrophy of the corpus callosum (CC) in Alzheimer's Disease (AD). However, it is currently unknown whether CC atrophy is associated with specific cortical volume changes in AD. Moreover, possible atrophy in extra-callosal commissures has not been examined to date. The purpose of the present study was to quantify atrophy in two cerebral commissures [the CC and the anterior commissure (AC)], to correlate this measure with cognitive status, and to relate commissural size to independent measures of temporal lobe volume in AD patients. METHODS: A sample of AD patients and of age- and education-matched normal control subjects (NCs) underwent MRI and a cognitive test battery including the Dementia Rating Scale and Mini Mental State examination. Mid-sagittal regional areas within CC and AC were measured along with superior, middle and inferior temporal lobes volumes. RESULTS: Alzheimer's Disease patients had significantly smaller callosa than did NCs. The callosal regions most affected in AD included the midbody, isthmus and genu. The isthmus and midbody areas of the CC were positively correlated with cognitive performance and with superior temporal lobe volume in AD patients. The mid-sagittal area of the AC and the superior temporal volumes did not differ between AD patients and NCs. CONCLUSIONS: The study demonstrated that the regional morphology of the CC correlates with current cognitive status and temporal lobe atrophy in AD. As well, the lack of difference for the AC suggests that commissural atrophy in AD is regionally specific.

Longitudinal change in hippocampal volume as a function of apolipoprotein E genotype.

The epsilon4 allele of the apolipoprotein E (APOE) gene confers an increased risk for the development of AD. The authors compared longitudinal rates of change in hippocampal volume as a function of APOE genotype in nondemented elderly individuals. Rate of volumetric loss was significantly greater among epsilon4+ compared with epsilon4- individuals. These results indicate that individuals positive for the APOE epsilon4 allele may show a greater rate of hippocampal atrophy than their epsilon4- counterparts, even in the absence of a diagnosis of AD.

The relationship between longitudinal declines in dehydroepiandrosterone sulfate concentrations and cognitive performance in older men.

BACKGROUND: The observation that dehydroepiandrosterone (DHEA) concentrations decrease markedly with age has led to the hypothesis that declining DHEA concentrations may contribute to age-related changes in cognition. In the United States, DHEA is widely available as an over-the-counter supplement that individuals are using in an effort to ameliorate age-related cognitive and physical changes. OBJECTIVE: To investigate the relationship between age-associated decreases in endogenous DHEA sulfate (DHEA-S) concentrations and declines in neuropsychological performance in a prospective, longitudinal study. METHODS: The subjects were 883 men from a community-dwelling volunteer sample in the Baltimore Longitudinal Study of Aging. The men were aged 22 to 91 years at the initial visit, and they were followed up for as long as 31 years (mean, 11. 55 years), with biennial reassessments of multiple cognitive domains and contemporaneous measurement of serum DHEA-S concentrations. Outcome measures were the results of cognitive tests of verbal and visual memory, 2 tests of mental status, phonemic and semantic word fluency tests, and measures of visuomotor scanning and attention. Serum DHEA-S concentrations were determined by standard radioimmunoassay. RESULTS: Neither the rates of decline in mean DHEA-S concentrations nor the mean DHEA-S concentrations within individuals were related to cognitive status or cognitive decline. A comparison between the highest and lowest DHEA-S quartiles revealed no cognitive differences, despite the fact that these groups differed in endogenous DHEA-S concentration by more than a factor of 4 for a mean duration of 12 years. CONCLUSION: Our longitudinal results augment those of previous prospective studies by suggesting that the decline in endogenous DHEA-S concentration is independent of cognitive status and cognitive decline in healthy aging men.

Salivary testosterone concentrations in left-handers: an association with cerebral language lateralization?

The level of testosterone exposure in early brain development may influence the direction or degree of cerebral language lateralization. Possible links between individual differences in testosterone levels and patterns of speech representation were investigated in 180 healthy young adults (97 left handed, 83 right handed) using the Fused Dichotic Words Test (T. Halwes, 1991). Among left-handed participants, significantly higher testosterone concentrations were observed in individuals with a left-ear advantage on dichotic listening than in individuals with a right-ear advantage. Among right-handed participants, the pattern of group differences in testosterone tended to be reversed, resulting in a statistically significant interaction. Results extend prior findings by S. D. Moffat and E. Hampson (1996a) and raise the possibility that higher testosterone is associated with patterns of brain organization in which speech and praxic functions are lateralized to the same hemisphere.