Papers by Steven Roodenrys
PLOS ONE
Introduction Prevalence of cognitive impairment increases with worsening severity of chronic kidn... more Introduction Prevalence of cognitive impairment increases with worsening severity of chronic kidney disease (CKD) and majority of end-stage kidney disease (ESKD) patients on dialysis have cognitive impairment. Trends of cognitive function (CF) in this population are less well known with published studies reporting conflicting results. Methods We assessed CF in a cohort of non-dialysis CKD and ESKD patients undergoing dialysis using modified mini-mental state examination (3MS), trail-making test (TMT-A & B) scores and Stroop task, and evaluated demographics, comorbidities and depression using Beck depression inventory at baseline. We repeated tests of CF and depression ≥ 1-year after baseline in both groups and compared change scores in CF and depression between ESKD/ CKD sub-groups. Among ESKD patients we compared change scores between patients with dialysis vintage of <1-year and >1-year. Analysis of covariance was used to adjust for the effect of age on these change scores. ...
Clinical Nutrition, 2021
BACKGROUND & AIMS Postprandial metabolic imbalances are important indicators of later develop... more BACKGROUND & AIMS Postprandial metabolic imbalances are important indicators of later developing cardiovascular disease (CVD). This study investigated the effects of food anthocyanins on vascular and microvascular function, and CVD associated biomarkers following a high fat high energy (HFHE) meal challenge in overweight older adults. METHODS Sixteen subjects (13 female, 3 male, mean age 65.9 SD 6.0 and body mass index 30.6 kg/m2 SD 3.9) participated in a crossover, randomized, controlled, double-blind clinical trial (registered under Australian New Zealand Clinical Trials Registry, identifier no. ACTRN12620000437965). Participants consumed a HFHE meal with a 250 mL dose of either intervention (anthocyanins-rich Queen Garnet Plum) or control (apricot) juice. Blood samples and blood pressure measures were collected at baseline, 2 h and 4 h following the HFHE meal. Vascular and microvascular function were evaluated at baseline and 2 h after the HFHE meal. RESULTS Participants had a higher 2 h postprandial flow-mediated dilatation (+1.14%) and a higher microvascular post-occlusive reactive hyperaemia (+0.10 perfusion units per mmHg) when allocated to the anthocyanin compared to the control arm (P = 0.019 and P = 0.049, respectively). C-reactive protein was lower 4 h postprandially in the anthocyanins (1.80 mg/L, IQR 0.90) vs control arm (2.30 mg/L, IQR 1.95) (P = 0.026), accompanied by a trend for lower concentrations of interleukin-6 (P = 0.075). No significant postprandial differences were observed between treatments for blood pressure, triacylglycerol, total cholesterol, serum derivatives of reactive oxidative metabolites, tumor necrosis factor alpha, interleukin-1 beta, or maximum microvascular perfusion following iontophoresis of acetylcholine. CONCLUSION Fruit-based anthocyanins attenuated the potential postprandial detrimental effects of a HFHE challenge on parameters of vascular and microvascular function, and inflammatory biomarkers in overweight older adults. Anthocyanins may reduce cardiovascular risk associated with endothelial dysfunction and inflammatory responses to a typical high fat 'Western' meal. Further studies are required to better elucidate the clinical implications of postprandial biomarkers of CVD.
British Journal of Psychology
SSRN Electronic Journal, 2022
Psychiatry, 2020
Objective: There is literature to suggest that anxious individuals may be lonely. Attentional bia... more Objective: There is literature to suggest that anxious individuals may be lonely. Attentional bias for threat (ABT), a mechanism implicated in the core symptoms of anxiety, has been linked to loneliness in a separate line of work. The primary aim of this study was to examine the role of loneliness in the association between ABT and anxiety. Method: An unselected sample of 260 individuals (196 Female; Mean Age = 22.43) completed measures of loneliness, ABT (a dot probe task), and anxiety. Two possible models of the role of loneliness in the ABT-anxiety link were tested using hierarchical regression analysis: (1) A moderation model (the ABT-anxiety link is moderated by loneliness), and (2) A proxy model (the ABT-anxiety link is better explained by loneliness). Results: In support of the latter model, ABT no longer predicted anxiety after the effects of loneliness had been accounted for. Additionally, ABT was associated with anxiety only when indexed using sadness-related scenes (but not fear-related scenes). Conclusions: Loneliness may be one important source of exaggerated threat appraisals which underpin the association between ABT and anxiety. Different classes of negative stimuli may be differentially sensitive to anxiety and should be a point of consideration in future research.
Schizophrenia Research: Cognition, 2017
Schizotypy is regarded as a trait vulnerability for psychotic disorders, yet alone is insufficien... more Schizotypy is regarded as a trait vulnerability for psychotic disorders, yet alone is insufficient for development of a diagnosable disorder. Additional symptoms and psychological distress are necessary for help seeking and transition from an at risk mental state to a clinical diagnosis. The present study investigated the interaction between trait schizotypy, state auditory verbal hallucination (AVH) predisposition, distress and handedness for the expression of neurological soft signs (NSS), a neurodevelopmental vulnerability factor for psychosis. Cluster analysis formed schizotypy groups statistically across the dimensions captured by the SPQ. It was hypothesized that schizotypy and AVH predisposition would interact, resulting in significantly greater NSS. Psychological distress and handedness were hypothesized to be significant covariates, accounting for some variance in the expression of NSS between the groups. A sample of University students (n = 327) completed the Schizotypal Personality Questionnaire, Launay-Slade Hallucination Scale, General Health Questionnaire and the Neurological Evaluation Scale (NES). Cluster Analysis revealed four schizotypy groups. Distress was not a significant covariate in any analysis. As expected, those with high overall schizotypy and high AVH predisposition expressed significantly greater Motor-Coordination NSS compared to those with high schizotypy and low AVH predisposition. Within the Mixed Interpersonal and Cognitive-Perceptual Schizotypy cluster, those with low AVH predisposition expressed significantly more Motor-Coordination NSS than those with high AVH predisposition. These findings suggest motor coordination NSS are detectable in schizotypy, and AVH predisposition appears to interact with these traits. This study highlights the importance of considering both trait and subclinical state risk factors when investigating risk for psychosis.
Journal of Nutrition in Gerontology and Geriatrics, 2016
A pilot quasi-experimental study investigated whether provision of pork, a rich source of thiamin... more A pilot quasi-experimental study investigated whether provision of pork, a rich source of thiamin, as the main protein source in meals four times/week for 12 weeks resulted in improved muscle mass, body strength, and cognitive function in community-living older adults compared to similar meals containing chicken. Retirement villages were randomized to receive pre-prepared frozen meals containing either pork or chicken. Dietary intake was assessed by three-day food records and cognitive domains assessed using validated tests. Hand grip strength was measured and lower extremity performance assessed by the sit-to-stand test, get-up-and-go test and six-minute walk test. Forty-eight volunteers participated (78.2 ± 6.2 y). In linear mixed models, controlling for baseline physical activity and dietary protein and energy intake, no differences were found between pork (n = 19) and chicken (n = 12) groups. The chicken group had improved Rey Auditory Verbal Learning test scores (verbal learning and memory) at six weeks (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Provision of four pork meals a week did not result in improvements in cognitive function, nor measures of strength or physical function, compared to those receiving chicken meals in healthy older adults. This suggests that merely changing the type of dietary protein provided by meat does not impact physical or cognitive function.
Psychopharmacology, 2010
Introduction The endogenous cannabinoid system is sensitive to the introduction of exogenous cann... more Introduction The endogenous cannabinoid system is sensitive to the introduction of exogenous cannabinoids such as delta-9tetrahydrocannabinol, which are known to impact upon memory functioning. We sought to examine the impact of chronic cannabis use upon memory-related brain function via examination of the subsequent memory effect (SME) of the event-related potential (ERP). Methods The SME is predictive of recall outcome and originates in structures that are dense with cannabinoid receptors (hippocampus and parahippocampus). The SME and performance on a verbal memory task were compared between 24 cannabis users (mean 17 years of near daily use) in the unintoxicated state and 24 non-using controls. The task involved the presentation of word lists, each with a short delay before recall. ERPs were recorded during encoding and later averaged by outcome (correctly recalled/ not recalled). Results Cannabis users showed poorer recall and altered patterns of SME activation: specifically, attenuation of the negative N4 and an increase in the late positive component. Duration of cannabis use and age of initial use correlated significantly with SME amplitudes. A longer history of use also correlated with greater recall that was related to N4 expression. Discussion The results indicate that relative to non-using controls, chronic users of cannabis have altered memoryrelated brain activation in the form of dysfunctional SME production and/or poorer neural efficiency, which is associated with deficits in memory recall. Greater alteration was associated with a longer history of cannabis use and an earlier onset of use. Neuroadaptation to the effects of chronic exposure may additionally play a role.
Journal of Experimental Psychology: Learning, Memory, and Cognition, 1997
Four experiments investigated the mechanisms responsible for the advantage enjoyed by high-freque... more Four experiments investigated the mechanisms responsible for the advantage enjoyed by high-frequency words in short-term memory tasks. Experiment 1 demonstrated effects of word frequency on memory span that were independent of differences in speech rate. Experiments 2 and 3 showed that word frequency has an increasing effect on serial recall across serial positions, but Experiment 4 showed that this effect was abolished for backward recall. A model that includes a redintegration process that operates to &quot;clean up&quot; decayed short-term memory traces is proposed, and the multinomial processing tree model described by R. Schweickert (1993) is used to provide a quantitative fit to data from Experiments 2, 3, and 4.
ADHD Attention Deficit and Hyperactivity Disorders, 2011
There is accumulating evidence that computerised cognitive training of inhibitory control and/or ... more There is accumulating evidence that computerised cognitive training of inhibitory control and/or working memory can lead to behavioural improvement in children with AD/HD. Using a randomised waitlist control design, the present study examined the effects of combined working memory and inhibitory control training, with and without passive attention monitoring via EEG, for children with and without AD/HD. One hundred and twenty-eight children (60 children with AD/HD, 68 without AD/HD) were randomly allocated to one of three training conditions (waitlist; working memory and inhibitory control with attention monitoring; working memory and inhibitory control without attention monitoring) and completed with pre- and post-training assessments of overt behaviour (from 2 sources), trained and untrained cognitive task performance, and resting EEG activity. The two active training conditions completed 25 sessions of training at home over a 4- 5-week period. Results showed significant improvements in overt behaviour for children with AD/HD in both training conditions compared to the waitlist condition as rated by a parent and other adult. Post-training improvements in the areas of spatial working memory, ignoring distracting stimuli, and sustained attention were reported for children with AD/HD. Children without AD/HD showed behavioural improvements after training. The improvements for both groups were maintained over the 6-week period following training. The passive attention monitoring via EEG had a minor effect on training outcomes. Overall, the results suggest that combined WM/IC training can result in improved behavioural control for children with and without AD/HD.
Cognitive Neuropsychiatry, 2021
ABSTRACT Introduction We aimed to investigate the association between schizotypy and intentionali... more ABSTRACT Introduction We aimed to investigate the association between schizotypy and intentionality bias, the tendency to interpret ambiguous actions as being intentional, for social and non-social actions separately. This bias contributes to interpersonal difficulties, and has been associated with psychotic symptoms, such as delusions. However, results have been inconsistent for an association between putative psychosis proneness, schizotypy, and intentionality bias. Further, the multidimensional nature of schizotypy has not been considered. Agreeableness was measured to examine the specificity of the relationship, and inhibition to examine its potential role as a mediator. Methods Two online studies are reported (n = 280 and n = 163) in which participants made intentionality judgements about ambiguous actions described in sentences. They also completed questionnaire measures of schizotypy and agreeableness, and inhibitory efficiency (a sentence completion task). Results Schizotypy was associated with perceiving ambiguous actions as intentional, particularly in social contexts, after controlling for agreeableness. The association with social intentionality was stronger for schizotypy subscales capturing paranoia and unusual beliefs. Inhibitory efficiency as not a significant predictor of intentionality bias. Conclusion These finding suggest intentionality biases for social and non-social events are distinguishable. In relation to schizotypy, social situations appear to generate perceptions of intentionality. Intentionality bias represents a phenotypic cognitive risk for psychosis which should be further investigated.
Cognitive Neuropsychiatry, 2021
ABSTRACT Introduction We aimed to investigate the association between schizotypy and intentionali... more ABSTRACT Introduction We aimed to investigate the association between schizotypy and intentionality bias, the tendency to interpret ambiguous actions as being intentional, for social and non-social actions separately. This bias contributes to interpersonal difficulties, and has been associated with psychotic symptoms, such as delusions. However, results have been inconsistent for an association between putative psychosis proneness, schizotypy, and intentionality bias. Further, the multidimensional nature of schizotypy has not been considered. Agreeableness was measured to examine the specificity of the relationship, and inhibition to examine its potential role as a mediator. Methods Two online studies are reported (n = 280 and n = 163) in which participants made intentionality judgements about ambiguous actions described in sentences. They also completed questionnaire measures of schizotypy and agreeableness, and inhibitory efficiency (a sentence completion task). Results Schizotypy was associated with perceiving ambiguous actions as intentional, particularly in social contexts, after controlling for agreeableness. The association with social intentionality was stronger for schizotypy subscales capturing paranoia and unusual beliefs. Inhibitory efficiency as not a significant predictor of intentionality bias. Conclusion These finding suggest intentionality biases for social and non-social events are distinguishable. In relation to schizotypy, social situations appear to generate perceptions of intentionality. Intentionality bias represents a phenotypic cognitive risk for psychosis which should be further investigated.
BMJ Open
ObjectivesLower health literacy (HL) is associated with poor outcomes in patients with kidney dis... more ObjectivesLower health literacy (HL) is associated with poor outcomes in patients with kidney disease. Since HL matches the patient’s competencies with the complexities of the care package, the level of HL sufficient in earlier stages of chronic kidney disease (CKD) may be inadequate for patients with end-stage kidney disease (ESKD) on dialysis. We aimed to analyse the HL profile of patients with ESKD and non-dialysis CKD and examine if there were significant associations with covariates which could be targeted to address HL deficits, thereby improving patient outcomes.Design and settingCross-sectional study of patients with CKD and ESKD from a single Australian health district.MethodsWe assessed the HL profile of 114 patients with CKD and 109 patients with ESKD using a 44-item multidomain Health Literacy Questionnaire (HLQ) and examined its association with demographic factors (age, gender, race), smoking, income, education, comorbidities, carer status, cognitive function and depre...
Memory
ABSTRACT The present study explored the influences of semantic features in immediate serial recal... more ABSTRACT The present study explored the influences of semantic features in immediate serial recall in order to further examine the involvement of semantic knowledge in short-term memory. The number of semantic features (NoF) was found to have a positive effect on short-term recall where high NoF words were remembered better than low NoF words (Experiment 1). This effect was replicated in a second experiment and was found to persist even after controlling for a potential confound (number of distinguishing features). It was further found that having more distinctive features facilitated recall performance of words whose representation was semantically poorer (Experiment 3). These results provide additional evidence of semantic influences in short-term memory and demonstrate that the organisation of semantic knowledge is reflected in short-term memory performance.
Frontiers in Psychology
© Copyright © 2020 de Leede-Smith, Roodenrys, Horsley, Matrini, Mison and Barkus. Semantic proces... more © Copyright © 2020 de Leede-Smith, Roodenrys, Horsley, Matrini, Mison and Barkus. Semantic processing underpins the organization of verbal information for both storage and retrieval. Deficits in semantic processing are associated with both the risk for and symptoms presented in schizophrenia. However, studies are mixed and could reflect the confounding effects of medication and symptom heterogeneity. Therefore, we considered whether two risk phenotypes, positive schizotypy and hallucinatory predisposition, present in the general population were associated with differential responding profiles for a semantic processing task. One hundred and eighty-three participants completed the Schizotypal Personality Questionnaire, Launay-Slade Hallucination Scale, National Adult Reading Test, a handedness measure, and a computerized semantic relatedness judgment task. Pairs of words were related through their dominant or subordinate meanings, or unrelated. Participants were divided into four groups using a mean split on cognitive-perceptual (positive) schizotypy and hallucination proneness. Significant differences between groups were found for reaction time on the semantic relatedness task, with the high cognitive-perceptual schizotypy groups responding significantly slower to all word pairs compared to their low scoring counterparts. There was some evidence that high hallucination proneness was associated with significantly faster reaction times which may reflect disinhibitive processes, however additional support is required. The results suggest that these two components of psychosis risk are associated with different patterns of responding to semantic processing. More diffuse activation of semantic information appeared to be associated with positive schizotypy, while those predisposed to hallucinations appeared to respond quicker. These results have significant implications in the re-conceptualization of hallucination proneness as distinct from positive schizotypy. Additional research is required to investigate the association between psychotic-like experiences separate from personality variables such as positive schizotypy and semantic processing.
Journal of Cognitive Psychology
word frequency effect, has been observed in multiple languages (e.g., English, French, Spanish), ... more word frequency effect, has been observed in multiple languages (e.g., English, French, Spanish), presentation modalities (visual and auditory), response modalities (e.g., spoken, typed, written, selected by mouse), recall directions (forward and backward) and memory tasks (e.g., immediate serial recall, reconstruction of order, memory span) (
Frontiers in Human Neuroscience
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Papers by Steven Roodenrys