Final year dental students in New Zealand: Self-reported confidence levels prior to BDS graduation

BACKGROUND AND OBJECTIVES

It is expected that the graduating dental student will have acquired the skills and knowledge to confidently treat most circumstances that they may encounter in private practice. The aims of this study were to evaluate final year dental students' self-reported levels of confidence in expected core skills just prior to graduation and to explore their career intentions both directly after graduating as well as in the longer term.

METHODS

After ethical approval was obtained, a survey and participant information sheet was distributed to all final year undergraduate dental students in 2014. Statistical analysis was carried out using SPSS version 22.0 with the alpha value set at 0.05.

RESULTS

The response rate was 69% (58/84). Most (44.8%) were going to be working in New Zealand private practices with 34.5% definitely considering specializing. The majority reported high self-confidence levels for sealant restorations (96.6%) and radiography (94.8%), while very few were confident in carrying out soft tissue biopsies (1 .8%) or restoring dental implants and treating medical emergencies (10.5%). Some gender differences were found.

CONCLUSIONS

The general finding was that most NZ graduates perceived themselves to be confident in managing the most fundamental aspects of general practice. Similar to their counterparts around the world, they will benefit from further mentoring and additional exposure to the more complex clinical tasks such as the restoration of implants and soft tissue biopsies.

Monitoring contaminants of emerging concern from tertiary wastewater treatment plants using passive sampling modelled with performance reference compounds

The Lake Simcoe watershed in Ontario, Canada is an important recreational area and a recharge zone for groundwater resources. Lake Simcoe is a relatively shallow lotic system that has been impacted by urban development, recreation, industry and agriculture. As part of a watershed management plan, six wastewater treatment plants (WWTPs) located in this catchment basin were selected to measure the inputs of contaminants of emerging concern (CECs) of wastewater origin. These WWTPs were recently upgraded to tertiary treatment for phosphorus removal. Polar organic chemical integrative samplers (POCIS) and semipermeable membrane devices (SPMDs) were used to monitor for hydrophilic and hydrophobic CECs, respectively, in treated and untreated wastewater. The passive samplers were calibrated with performance reference compounds (PRCs) by measuring the loss of deuterated beta blocker drugs spiked into POCIS and the loss of PCB congeners spiked into SPMDs over the course of 14-day deployment periods. From the PRC data, field sampling rates of CECs were determined and applied to estimate time-weighted average (TWA) concentrations and mass loadings in mg/day/1000 members of the population serviced. In treated wastewater, TWA concentrations of an antibiotic, sulfamethoxazole, the prescription drugs, carbamazepine, naproxen and gemfibrozil, and the non-prescription drug, ibuprofen, were estimated to be in the low (<18 ng/L) range. The artificial sweeteners, sucralose and acesulfame, were particularly useful chemical tracers, with estimated TWA concentrations in treated wastewater ranging from 128 to 213 ng/L and 4 to 33 ng/L, respectively. The steroid hormones were detected only rarely in treated wastewater. Triclosan, triclocarban and the synthetic musks, HHCB and AHTN, were removed efficiently (>77 %), possibly because of the tertiary treatment technologies. Therefore, the mass loadings for these personal care products were all <5 mg/day/1000 people. Overall, this study indicates that tertiary treatment technologies designed for phosphorus removal do not entirely remove the target CECs.

Decomposing the First Absorption Band of OCS Using Photofragment Excitation Spectroscopy

Photofragment excitation spectra of carbonyl sulfide (OCS) have been recorded from 212-260 nm by state-selectively probing either electronically excited S((1)D) or ground state S((3)P) photolysis products via 2 + 1 resonance-enhanced multiphoton ionization. Probing the major S((1)D) product results in a broad, unstructured action spectrum that reproduces the overall shape of the first absorption band. In contrast, spectra obtained probing S((3)P) products display prominent resonances superimposed on a broad continuum; the resonances correspond to the diffuse vibrational structure observed in the conventional absorption spectrum. The vibrational structure is assigned to four progressions, each dominated by the C-S stretch, ν1, following direct excitation to quasi-bound singlet and triplet states. The S((3)PJ) products are formed with a near-statistical population distribution over the J = 2, 1, and 0 spin-orbit levels across the wavelength range investigated. Although a minor contributor to the S atom yield near the peak of the absorption cross section, the relative yield of S((3)P) increases significantly at longer wavelengths. The experimental measurements validate recent theoretical work characterizing the electronic states responsible for the first absorption band by Schmidt and co-workers.

Sociometry and Athletic Status of Adolescents, Critical Review of Research Literature

A review of literature on the relationship between measures of social acceptability and motor characteristics is presented: data inconsistencies are commented on and a plea made for further disciplined studies.

Couples' shared experiences of dementia: a meta-synthesis of the impact upon relationships and couplehood

OBJECTIVES

There is a growing recognition of dementia as a condition that affects both members of a couple individually while also influencing the relational bond between them. This is an area which potentially has important service implications. Accordingly, the aim of this review was to elaborate the experience of dementia on partner/spousal relationships through a synthesis of pertinent qualitative literature.

METHOD

A systematic literature search for qualitative research papers was undertaken in November 2013. Five databases (Academic Search Complete, CINAHL, MEDLINE, PsycARTICLES and PsycINFO) were searched using terms for dementia, partner and qualitative data analysis. Meta-synthesis was conducted on the data within the found papers.

RESULTS

A line-of-argument synthesis of 10 studies yielded four overarching themes, which highlight couples' efforts to maintain their sense of togetherness; shifts in balance and power within their relationship which can impact upon both partners' sense of identity; the empathy and sensitive attunement between couples as they work to protect each other's sense of role and identity; and the resilience couples demonstrate in the face of great fear, uncertainty and hopelessness.

CONCLUSION

Findings have important implications for both research and practice, particularly the need for services to support couples' efforts to enhance couplehood in spite of dementia. Ultimately, this review adds further weight to arguments to refocus dementia care on relationships in addition to individuals.

Knowledge, opinions and factors influencing practices regarding sugar in oral paediatric medications: a survey of Dunedin pharmacy staff

BACKGROUND AND OBJECTIVES

Sugar, a known aetiological factor in dental decay, has been used in paediatric medications as a bulking agent, preservative and to improve taste. Although artificial sweeteners have largely replaced sugar, some prescribed and over-the-counter (OTC) paediatric medications and supplements containing sugar are still available in New Zealand. Little is currently known about the knowledge, opinions and practices of staff in NZ pharmacies regarding sugar-containing paediatric medications. This study was carried out to investigate these factors.

METHODS

After ethical approval was obtained, questionnaires were delivered to all staff members at pharmacies in the greater Dunedin area. Quantitative statistical analysis was carried out using SPSS version 22.0 with the alpha value set at 0.05. Qualitative data were analysed using a general inductive technique.

RESULTS

A total of 58 questionnaires were returned giving a pharmacy response rate of 63.0%. Some 29.9% of respondents thought the inclusion of sugar in medications necessary and 77.6% agreed that sugar in paediatric medications can contribute to dental decay. Most of the 67.2% who reported that they do not give advice to customers regarding sugar in medications and oral health, felt it was not a priority. Parental request was the main factor determining provision or recommendations regarding sugar-free options (87.9%).

CONCLUSION

Although choice of a sugar-free medication can be limited by many factors, inter-professional collaboration and knowledge sharing on this topic would be advantageous. In addition, the provision of more formalised education, either as part of undergraduate pharmacy curricula or as part of continuing education, should be considered.

Maternal experiences of embodied emotional sensations during breast feeding: An Interpretative Phenomenological Analysis

OBJECTIVE

the purpose of this study was to explore mothers׳ experiences of embodied emotional sensations during breast feeding and to understand the meaning and consequences that such experiences may have on mothers' sense of self and the relationships they form with their children.

DESIGN

a qualitative design was applied to this study as it was judged as the most appropriate approach to this novel field of enquiry.

SETTING

the study was conducted in United Kingdom using a sample of mothers drawn from five different countries from Europe, America and Australia.

PARTICIPANTS

the sample consisted of 11 mothers who reported experiencing or having experienced negative embodied emotional sensations associated with breast feeding in the past five years.

MEASUREMENTS

semi-structured interviews were conducted with the mothers and interviews were transcribed to enable the process of data analysis. Interpretative Phenomenological Analysis (IPA; Smith et al., 2009a, 2009b) was chosen as a method of data analysis, enabling in depth understanding and interpretation of the meaning of mothers' experiences. IPA was chosen due to its idiographic commitment and particular interest in sense-making, phenomenology and hermeneutics.

FINDINGS

three themes were generated reflecting the multifaceted nature of breast feeding experiences (i) 'Breast feeding: An unexpected trigger of intense embodied emotional sensations incongruent with view of self', (ii) 'Fulfilling maternal expectations and maintaining closeness with the child', (iii) 'Making sense of embodied emotional sensations essential to acceptance and coping'.

CONCLUSIONS

breast feeding has the potential to trigger a range of conflicting cognitions and emotions in mothers that may impact on how mothers view themselves and relate to their children.

IMPLICATIONS FOR PRACTICE

increasing awareness about emotional breast feeding experiences and recognising the multifaceted, individual nature of difficulties around breast feeding enables professionals to offer mothers person-centred care and avoid making clinical decisions and recommendations based on inaccurate knowledge.

Dental implant treatment following trauma: An investigation into the failure to complete Accident Compensation Corporation funded care

BACKGROUND AND OBJECTIVES

Among other restorative strategies, the Accident Compensation Corporation (ACC) provides benefits for dental implant treatment to replace teeth lost as a result of trauma. While ACC has funded over 15,000 dental implants since 2002, the outcomes of this treatment and patient perceptions of this treatment have not been investigated. The aim of this study was to investigate the perceptions of the dental implant treatment outcomes and reasons for failure to complete restorative treatment in patients who had undergone trauma-related implant surgery funded by ACC between February 2006 and September 2009, but had not completed the prosthetic component of the treatment.

METHODS

A randomly selected sample of 399 patients, who had undergone dental implant surgery but not completed the crown restoration, was identified from the ACC database. These individuals were contacted by mail for expressions of interest and 181 clients were interviewed by telephone. Responses to open-ended questions were entered into an Excel spreadsheet and analysed using a general inductive technique.

RESULTS

A common emergent theme was the high level of satisfaction expressed by participants with the implant process, however just under half of those responding felt they had been pushed into having implants and were given the impression that this was the only treatment ACC paid for. The cost of the prosthetic phase of the treatment and surgical complications were identified as the primary reasons why participants failed to complete the restorative phase of treatment, after completing the surgical phase.

CONCLUSIONS

The results highlighted the need to better inform patients of their treatment options and to allow time for them to process this information before progressing with care. A patient decision tool may help to give greater ownership of the treatment options. Newly implemented protocols to assist dentists to better assess treatment needs may also assist in achieving improvements in perceived treatment outcomes for patients.

Near-UV photodissociation dynamics of CH2I2

The near-UV photodissociation dynamics of CH₂I₂has been investigated using a combination of velocity-map (slice) ion imaging andab initiocalculations characterizing the excited states.

Dynamics and spectroscopy of CH2OO excited electronic states

Ab initio molecular dynamics with a high level of theory is used to explore the fate of a Criegee intermediate after an initial electronic excitation. Results are confronted with experiments.

New approaches towards chronic pain: patient experiences of a solution-focused pain management programme

Research has suggested that Solution-Focused Brief Therapy (SFBT) may be effective in facilitating meaningful change for those living with chronic pain. This study aimed to further this understanding through exploring the experiences of people living with chronic pain, who had attended an 8-week solution-focused pain management programme. The design of this study was conducted in consultation with a service-user advisory group, and employed a qualitative and interpretative design rooted in critical community psychology, participatory research frameworks and emancipatory disability research. Five participants opted-in to the study following an opportunity sampling method of persons who had attended a programme in the last 18 months. Interviews were transcribed verbatim and analysed using inductive thematic analysis. Five main themes were identified: 'Accessing the pain management programme', 'A solution-focused group', 'The solution-focused clinician', 'Solutions and changes' and 'Challenges and improvements'. Clinical and research implications of the findings are discussed.

SUMMARY POINTS

There has been an international proliferation of pain management programmes (PMPs) aimed at helping those with chronic pain to live well, despite an unremitting condition.Arguably, the most popular psychological approaches used within PMPs are informed by cognitive behavioural therapy (CBT).Despite a supportive evidence base for psychological approaches in pain management, there is a recognised need for further research into alternative approaches and their effectiveness.Emerging research and policy recommendations are beginning to value the expertise of those living with chronic conditions, particularly how these perspectives can be used to develop effective treatments and services.SFBT is an approach aimed at achieving a patient's goals or 'preferred future' through identifying and utilising their expertise. SFBT may have significant efficacy in helping those with chronic conditions to live improved, meaningful lives.

Family members' experience of seeking help for first-episode psychosis on behalf of a loved one: a meta-synthesis of qualitative research

AIM

Family members often play a vital role in seeking help for loved ones experiencing first-episode psychosis. Understanding this experience is crucial in facilitating the help-seeking process. Qualitative research offers valuable insight into the lived experience of family members who seek help on behalf of a loved one experiencing first-episode psychosis.

METHOD

The current research presents a systematic review of qualitative studies exploring the family member experience of seeking help for first-episode psychosis.

RESULTS

A meta-synthesis of 13 qualitative studies has revealed four themes relating to family members' experience of seeking help for first-episode psychosis. These include a sense of not knowing, the reaching of crisis point, the impact upon the family member and the mediating role of interactions with others. A further synthesis of translation captures the interaction of these themes within this experience.

CONCLUSIONS

The findings provide a novel insight into this experience, suggesting implications for clinical practice. These include a focus upon the facilitation of early positive interactions with family members and for first-episode psychosis to be presented to families in a normalizing manner. The need for future research that examines the experience of those who do not seek help from health services is discussed.

Choosing chemical markers for quality assurance of complex herbal medicines: Development and application of the herb MaRS criteria

With increasing use of herbal medicines for chronic or serious illness, relevant quality assurance methods are essential for making claims of therapeutic benefit. Adequate demonstration of safety and efficacy based on chemical composition and ensuring consistency between manufactured batches is critical. To date, there has been no uniform standard approach or detailed framework provided to industry for selecting relevant chemical markers used to standardize herbal products. We developed the Herbal Marker Ranking System (Herb MaRS) providing guidance on prioritizing the selection of chemical markers for quality control of complex multi-herb mixtures, while also taking into account the bioactivity in relation to the symptoms of the disease and its concentration in the formula. We apply the Herb MaRS evaluation criteria to a seven-herb formulation for the treatment of irritable bowel syndrome with constipation. Our ranking scale accommodates the clinical and pharmacological use of the formulation and its claimed indications.

High resolution absolute absorption cross sections of the B̃1A′–X̃1A′ transition of the CH2OO biradical

Carbonyl oxides, or Criegee intermediates, are formed from the gas phase ozonolysis of alkenes and play a pivotal role in night-time and urban area atmospheric chemistry.

Removal of selected pharmaceuticals, personal care products and artificial sweetener in an aerated sewage lagoon

A sewage lagoon serving the small municipality of Lakefield in Ontario, Canada was monitored in the summer, fall and winter to determine removals of carbamazepine, trimethoprim, sulfamethoxazole, ibuprofen, gemfibrozil, triclosan, sucralose, HHCB and AHTN. Concentrations of these compounds in untreated and treated wastewater were estimated by deploying POCIS and SPMD passive samplers in the sewage lagoon. Passive samplers were also deployed at several points upstream and downstream of the point of discharge from the lagoon into the Otonabee River. LC-MS/MS and GC-MS were utilized to determine the concentrations of pharmaceuticals and personal care products (PPCPs) and sucralose, an artificial sweetener. Among PPCPs sampled by POCIS, the highest estimated concentration in untreated wastewater was ibuprofen sampled during the fall, at an estimated concentration of 60.3 ng/L. The estimated average concentration of sucralose was 13.6 ng/L in the untreated wastewaters. Triclosan, HHCB and AHTN in SPMDs were highest during fall season, at 30, 1677 and 109 ng/L, respectively. For all compounds except gemfibrozil, carbamazepine and sucralose, removals were highest in the summer (83.0 to 98.8%) relative to removals in the fall (48.4 to 91.4%) and winter (14.0 to 78.3%). Finally, the estimated concentrations of carbamazepine, sulfamethoxazole, triclosan and HHCB were compared with predicted values obtained through application of the WEST® modeling tool, with a new model based on the River Water Quality Model No. 1 and extended with dynamic mass balances describing the fate of chemicals of emerging concern subject to a variety of removal pathways. The model was able to adequately predict the fate of these four compounds in the lagoon in summer and winter, but the model overestimated removals of three of the four test compounds in the fall sampling period. This lagoon was as effective at removing PPCPs as many conventional WWTPs, but removals were better during the summer.

Monitoring for contaminants of emerging concern in drinking water using POCIS passive samplers

Contaminants of emerging concern (CEC) have been detected in drinking water world-wide. The source of most of these compounds is generally attributed to contamination from municipal wastewater. Traditional water sampling methods (grab or composite) often require the concentration of large amounts of water in order to detect trace levels of these contaminants. The Polar Organic Compounds Integrative Sampler (POCIS) is a passive sampling technology that has been developed to concentrate trace levels of CEC to provide time-weighted average concentrations for individual compounds in water. However, few studies to date have evaluated whether POCIS is suitable for monitoring contaminants in drinking water. In this study, the POCIS was evaluated as a monitoring tool for CEC in drinking water over a period of 2 and 4 weeks with comparisons to typical grab samples. Seven "indicator compounds" which included carbamazepine, trimethoprim, sulfamethoxazole, ibuprofen, gemfibrozil, estrone and sucralose, were monitored in five drinking water treatment plants (DWTPs) in Ontario. All indicator compounds were detected in raw water samples from the POCIS in comparison to six from grab samples. Similarly, four compounds were detected in grab samples of treated drinking water, whereas six were detected in the POCIS. Sucralose was the only compound that was detected consistently at all five plants. The POCIS technique provided integrative exposures of CECs in drinking water at lower detection limits, while episodic events were captured via traditional sampling methods. There was evidence that the accumulation of target compounds by POCIS is a dynamic process, with adsorption and desorption on the sorbent occurring in response to ambient levels of the target compounds in water. CECs in treated drinking water were present at low ng L(-1) concentrations, which are not considered to be a threat to human health.

Morphologic, distributional, volumetric, and intensity characterization of periventricular hyperintensities

BACKGROUND AND PURPOSE

White matter hyperintensities are characteristic of old age and identifiable on FLAIR and T2-weighted MR imaging. They are typically separated into periventricular or deep categories. It is unclear whether the innermost segment of periventricular white matter hyperintensities is truly abnormal or is imaging artifacts.

MATERIALS AND METHODS

We used FLAIR MR imaging from 665 community-dwelling subjects 72-73 years of age without dementia. Periventricular white matter hyperintensities were visually allocated into 4 categories: 1) thin white line; 2) thick rim; 3) penetrating toward or confluent with deep white matter hyperintensities; and 4) diffuse ill-defined, labeled as "subtle extended periventricular white matter hyperintensities." We measured the maximum intensity and width of the periventricular white matter hyperintensities, mapped all white matter hyperintensities in 3D, and investigated associations between each category and hypertension, stroke, diabetes, hypercholesterolemia, cardiovascular disease, and total white matter hyperintensity volume.

RESULTS

The intensity patterns and morphologic features were different for each periventricular white matter hyperintensity category. Both the widths (r = 0.61, P < .001) and intensities (r = 0.51, P < .001) correlated with total white matter hyperintensity volume and with each other (r = 0.55, P < .001) for all categories with the exception of subtle extended periventricular white matter hyperintensities, largely characterized by evidence of erratic, ill-defined, and fragmented pale white matter hyperintensities (width: r = 0.02, P = .11; intensity: r = 0.02, P = .84). The prevalence of hypertension, hypercholesterolemia, and neuroradiologic evidence of stroke increased from periventricular white matter hyperintensity categories 1 to 3. The mean periventricular white matter hyperintensity width was significantly larger in subjects with hypertension (mean difference = 0.5 mm, P = .029) or evidence of stroke (mean difference = 1 mm, P < .001). 3D mapping revealed that periventricular white matter hyperintensities were discontinuous with deep white matter hyperintensities in all categories, except only in particular regions in brains with category 3.

CONCLUSIONS

Periventricular white matter hyperintensity intensity levels, distribution, and association with risk factors and disease suggest that in old age, these are true tissue abnormalities and therefore should not be dismissed as artifacts. Dichotomizing periventricular and deep white matter hyperintensities by continuity from the ventricle edge toward the deep white matter is possible.

Neuroticism, depressive symptoms and white-matter integrity in the Lothian Birth Cohort 1936

BACKGROUND

Clinical depression is associated with reductions in white-matter integrity in several long tracts of the brain. The extent to which these findings are localized or related to depressive symptoms or personality traits linked to disease risk remains unclear. Method Members of the Lothian Birth Cohort 1936 (LBC936) were assessed in two waves at mean ages of 70 and 73 years. At wave 1, they underwent assessments of depressive symptoms and the personality traits of neuroticism and extraversion. Brain diffusion magnetic resonance imaging (MRI) data were obtained at the second wave and mood assessments were repeated. We tested whether depressive symptoms were related to reduced white-matter tract fractional anisotropy (FA), a measure of integrity, and then examined whether high neuroticism or low extraversion mediated this relationship.

RESULTS

Six hundred and sixty-eight participants provided useable data. Bilateral uncinate fasciculus FA was significantly negatively associated with depressive symptoms at both waves (standardized β=0.12-0.16). Higher neuroticism and lower extraversion were also significantly associated with lower uncinate FA bilaterally (standardized β=0.09-0.15) and significantly mediated the relationship between FA and depressive symptoms.

CONCLUSIONS

Trait liability to depression and depressive symptoms are associated with reduced structural connectivity in tracts connecting the prefrontal cortex with the amygdala and anterior temporal cortex. These effects suggest that frontotemporal disconnection is linked to the etiology of depression, in part through personality trait differences.

An investigation into adolescents' experience of cognitive behavioural therapy within a child and adolescent mental health service

Cognitive Behavioural Therapy (CBT) is frequently referenced within NICE (National Institute for Clinical Excellence) guidance and is a recommended psychological therapy for a number of different mental health disorders for both adults and children. This is due to the current body of quantitative research around CBT demonstrating its efficacy for a range of mental health difficulties. However, CBT has not been as well addressed within the qualitative field and this gap in research is even more obvious when looking at CBT conducted with children and adolescents. This interpretative phenomenological study explored adolescents' experiences of a course of CBT within a Child and Adolescent Mental Health Service (CAMHS) in a one-to-one format. Three female adolescents who had completed an agreed contract of therapy with the CBT service took part in semi-structured interviews. Four superordinate themes emerged from analysis and highlighted components within CBT that were important to the sample. These were engagement, the therapeutic relationship, the impact of CBT on change and the manner in which CBT was delivered. The findings are discussed with relevance to current policy and pertinent literature as well as implications for service delivery and future research.

A qualitative exploration into young children's perspectives and understandings of emotional difficulties in other children

Research into children's perspectives and understandings of emotional difficulties is limited and methodologically varied. In this paper we explore young children's perspectives and understandings of emotional difficulties in their peers. We conducted five focus groups involving a total of 25 children. The children, aged eight and nine, were presented with vignettes representing peers experiencing emotional difficulties, and invited to discuss their perspectives on possible causes. We also explored their emotional and behavioural reactions to the vignette characters. Using interpretative phenomenological analysis we identified three themes: Searching for an Explanation; Empathy versus Blame; and Consequences and Solutions. The children drew on their own emotional experiences in their sense-making, and the extent to which they held the character responsible for their behaviour was particularly important in influencing their responses towards the characters.

Bipolar Disorder is a two-edged sword: a qualitative study to understand the positive edge

BACKGROUND

Bipolar Disorder (BD) can have highly detrimental effects on the lives of people with the diagnosis and those who care about them. However, growing evidence suggests that aspects of bipolar experiences are also highly valued by some people.

METHOD

We aimed to understand how participants with a diagnosis of BD made sense of what they took to be positive about their bipolar experiences. Interpretative Phenomenological Analysis was used in the collection and analysis of data from 10 individuals in the UK.

RESULTS

Positive aspects were numerous, highly valued and participants welcomed the opportunity to discuss them. Three important themes emerged: 1) Direct positive impact of bipolar experiences on everyday life including amplification of internal states, enhanced abilities and more intense human connectedness; 2) Lucky to be bipolar - the sense of having been given a special gift; 3) Relationship between the self and bipolar experiences. Limitations Given the small size, further research is needed to explore how widely positive aspects of BD are experienced.

CONCLUSIONS

These themes highlight the need to invite people to talk about the positive aspects of their bipolar experiences as well as the difficulties they face. This may help us to understand ambivalence to current treatment and to develop interventions that minimise the negative impacts, whilst recognising and potentially retaining some of the positives.

Brain white matter tract integrity as a neural foundation for general intelligence

General intelligence is a robust predictor of important life outcomes, including educational and occupational attainment, successfully managing everyday life situations, good health and longevity. Some neuronal correlates of intelligence have been discovered, mainly indicating that larger cortices in widespread parieto-frontal brain networks and efficient neuronal information processing support higher intelligence. However, there is a lack of established associations between general intelligence and any basic structural brain parameters that have a clear functional meaning. Here, we provide evidence that lower brain-wide white matter tract integrity exerts a substantial negative effect on general intelligence through reduced information-processing speed. Structural brain magnetic resonance imaging scans were acquired from 420 older adults in their early 70s. Using quantitative tractography, we measured fractional anisotropy and two white matter integrity biomarkers that are novel to the study of intelligence: longitudinal relaxation time (T1) and magnetisation transfer ratio. Substantial correlations among 12 major white matter tracts studied allowed the extraction of three general factors of biomarker-specific brain-wide white matter tract integrity. Each was independently associated with general intelligence, together explaining 10% of the variance, and their effect was completely mediated by information-processing speed. Unlike most previously established neurostructural correlates of intelligence, these findings suggest a functionally plausible model of intelligence, where structurally intact axonal fibres across the brain provide the neuroanatomical infrastructure for fast information processing within widespread brain networks, supporting general intelligence.