Living in the Fast Lane: The Role of Temporal Processing in ADHD Risk-taking Behaviors

Background: Attention Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder, prevalent in the college student population, that is associated with temporal processing deficits and functional impairments, namely engagement in risky behaviors (ERB; e.g., binge drinking). An existing theoretical framework purposes that aberrant temporal processing and subjective experience of time passing slowly, experienced in individuals with a fast internal clock (e.g., individuals with ADHD), increases the likelihood of ERB. The primary aim of this project is to improve our understanding of the relationship between objective temporal processing deficits and the subjective experience of time passage among people with elevated ADHD symptoms. Method: The present study used the Wittmann and Paulus (2008) theoretical framework to examine (a) relationships between objective and subjective temporal processing and ADHD symptoms and (b) associations between these variables and ERB. A novel measure of temporal processing (the Time Management and Estimation Scale, TiME) was revised from a pilot study and assessed via factor analysis and tested for reliability and validity to be used as a predictor variable in subsequent analyses. College student participants (N=215) completed measures of current ADHD symptoms, objective measures of temporal processing, ERB, the TiME, and relevant covariates (e.g., delay aversion, impulsivity). Linear regressions analyzed the associations between ADHD symptoms, objective temporal processing, and subjective (self-report) temporal processing, and negative binomial regressions analyzed the associations between these variables and ERB. Results: Factor analysis indicated a four-factor structure of the TiME. The TiME demonstrated good reliability to be used in subsequent analyses, but validity was only partially established for the TiME. Concurrent validity with the TiME and procrastination, but not objective measures of temporal processing or ADHD, was established. Overall, objective and subjective measures of temporal processing were not significantly associated with ADHD symptoms. ADHD symptom severity and temporal processing self-report were significantly associated with greater engagement in academic risk behaviors (e.g., missing class, not completing assignments). Time estimation accuracy was associated with lower engagement in risky sexual behavior (e.g., condomless sex) and aggressive behavior (e.g., hitting someone). No other significant associations were found between the predictor variables and ERB. The interaction between ADHD symptoms and subjective temporal processing was not associated with ERB. Discussion: The present study established preliminary evidence for the reliability of a novel self-report measure of temporal processing, yet there was a lack of concurrent validity evidence supporting associations between ADHD symptoms and subjective and objective temporal processing skills in college students. Objective time estimation accuracy was associated with decreased engagement in sexual or aggressive risky behaviors. Future research should continue to investigate if temporal processing deficits are present in college students with ADHD and clinically significant impairments associated with these deficits

Distinguishing Performance on Tests of Executive Functions Between Those with Depression and Anxiety

Objective: To see if there are differences in executive functions between those diagnosed with Major Depressive Disorder (MDD) and those with Generalized Anxiety Disorder (GAD).Participants and Methods: The data were chosen from a de-identified database at a neuropsychological clinic in South Florida. The sample used was adults diagnosed with MDD (n=75) and GAD (n=71) and who had taken the Halstead Category Test, Trail Making Test, Stroop Test, and the Wisconsin Card Sorting Test. Age (M=32.97, SD=11.75), gender (56.7% female), and race (52.7% White) did not differ between groups. IQ did not differ but education did (MDD=13.41 years, SD=2.45; GAD=15.11 years, SD=2.40), so it was ran as a covariate in the analyses. Six ANCOVAs were run separately with diagnosis being held as the fixed factor and executive function test scores held as dependent variables. Results: The MDD group only performed worse on the Category Test than the GAD group ([1,132]=4.022, p\u3c .05). Even though both WCST scores used were significantly different between the two groups, both analyses failed Levene’s test of Equality of Error Variances, so the data were not interpreted. Conclusions: Due to previous findings that those diagnosed with MDD perform worse on tests of executive function than normal controls (Veiel, 1997), this study wanted to compare executive function performance between those diagnosed with MDD and those with another common psychological disorder. The fact that these two groups only differed on the Category Test shows that there may not be much of a difference in executive function deficits between those with MDD and GAD. That being said, not being able to interpret the scores on the WCST test due to a lack of homogeneity of variance indicates that a larger sample size is needed to compare these two types of patients, as significant differences may be found. The results of this specific study, however, could mean that the Category Test could be used in assisting the diagnosis of a MDD patient

Effects of Diversity and Neuropsychological Performance in an NFL Cohort

Objective: The aim of this study was to examine the effect of ethnicity on neuropsychological test performance by comparing scores of white and black former NFL athletes on each subtest of the WMS. Participants and Methods: Data was derived from a de-identified database in South Florida consisting of 63 former NFL white (n=28, 44.4%) and black (n=35, 55.6%) athletes (Mage= 50.38; SD= 11.57). Participants completed the following subtests of the WMS: Logical Memory I and II, Verbal Paired Associates I and II, and Visual Reproduction I and II. Results: A One-Way ANOVA yielded significant effect between ethnicity and performance on several subtests from the WMS-IV. Black athletes had significantly lower scores compared to white athletes on Logical Memory II: F(1,61) = 4.667, p= .035, Verbal Paired Associates I: F(1,61) = 4.536, p = .037, Verbal Paired Associates: II F(1,61) = 4.677, p = .034, and Visual Reproduction I: F(1,61) = 6.562, p = .013. Conclusions: Results suggest significant differences exist between white and black athletes on neuropsychological test performance, necessitating the need for proper normative samples for each ethnic group. It is possible the differences found can be explained by the psychometric properties of the assessment and possibility of a non-representative sample for minorities, or simply individual differences. Previous literature has found white individuals to outperform African-Americans on verbal and non-verbal cognitive tasks after controlling for socioeconomic and other demographic variables (Manly & Jacobs, 2002). This highlights the need for future investigators to identify cultural factors and evaluate how ethnicity specifically plays a role on neuropsychological test performance. Notably, differences between ethnic groups can have significant implications when evaluating a sample of former athletes for cognitive impairment, as these results suggest retired NFL minorities may be more impaired compared to retired NFL white athletes

Regional Cerebral Blood Flow Patterns in Children vs. Adults with ADHD Combined and Inattentive Types: A SPECT Study

Objective: The current study sought to determine whether ADHD Combined Type (ADHD-C) and ADHD Primarily Inattentive Type (ADHD-PI) showed differential regional cerebral blood flow (rCBF) patterns in children vs. adults. Participants and Methods: The overall sample (N=1484) was effectively split into four groups: adults with ADHD-PI (n=519), adults with ADHD-C (n=405), children with ADHD-PI (n=192), children with ADHD-C (n=368). All participants were void of bipolar, schizophrenia, autism, neurocognitive disorders, and TBI. The data were collected from a de-identified archival database of individuals who underwent SPECT scans at rest. Results: Using αConclusions: Overall, the current study suggested that children may show rCBF differences between different ADHD subtypes, but adults may not. The current study did not find significance in any of the 17 brain regions examined when comparing adults with ADHD-C to adults with ADHD-PI. All significant findings were attributed to the children with ADHD-C group showing aberrant blood flow rate than at least one other group. Previous research has supported that the differentiation of these subtypes as distinctive disorders is difficult to make in adults (Sobanski et al., 2006). Other research has indicated the potential of imaging techniques to differentiate the two in children (Al-Amin, Zinchenko, & Geyer, 2018). The current findings support nuanced ways in which rCBF patterns of ADHD-C and ADHD-PI differ between children and adults

The Effect of Ethnicity on Neuropsychological Test Performance of Former NFL Athletes

Objective: To investigate the effect of ethnicity on neuropsychological test performance by specifically exploring differences between white and black former NFL athletes on subtests of the WAIS-IV. Participants and Methods: Data was derived from a de-identified database in Florida consisting of 63 former NFL athletes (Mage=50.38; SD=11.57); 28 white and 35 black. Participants completed the following subtests of the WAIS-IV: Block Design, Similarities, Digit Span, Matrix Reasoning, Arithmetic, Symbol Search, Visual Puzzles, Coding, and Cancellation. Results: One-Way ANOVA yielded a significant effect between ethnicity and performance on several subtests. Black athletes had significantly lower scaled scores than white athletes on Block Design F(1,61)=14.266, p\u3c.001, Similarities F(1,61)=5.904, p=.018, Digit Span F(1,61)=8.985, p=.004, Arithmetic F(1,61)=16.07, p\u3c.001 and Visual Puzzles F(1,61)=16.682, p\u3c .001. No effect of ethnicity was seen on performance of Matrix Reasoning F(1,61)=2.937, p=.092, Symbol Search F(1,61)=3.619, p=.062, Coding F(1,61)=3.032, p=.087 or Cancellation F(1,61)=2.289, p=.136. Conclusions: Results reveal significant differences between white and black athletes on all subtests of the WAIS-IV but those from the Processing Speed Scale and Matrix Reasoning. These findings align with previous literature that found white individuals to outperform African-Americans on verbal and non-verbal tasks after controlling for socioeconomic and demographic variables (Manly & Jacobs, 2002). These differences may also be a reflection of the WAIS-IV’s psychometric properties and it is significant to consider the normative sample used may not be appropriate for African-Americans. This study highlights the need for future research to identify how ethnicity specifically influences performance, sheds light on the importance of considering cultural factors when interpreting test results, and serves as a call to action to further understand how and why minorities may not be accurately represented in neuropsychological testing

Improving community walking after stroke; the effect of dual task treadmill training on gait, cognition and brain control mechanisms of dual task walking in chronic stroke survivors

It is well known that improving community walking ability is one of the major goals in stroke rehabilitation. Even if motor recovery of the lower limbs does occur, the ability to walk in the community is often still impaired. This thesis set out to explore dual task ability after stroke in relation to community walking and explored dual task treadmill training in stroke survivors. In addition, functional magnetic resonance imaging (fMRI) and functional near-infrared spectroscopy (fNIRS) in stroke survivors during single and dual gait movements were performed to examine dual task effects on brain activation before and after dual task training. In a cross-sectional trial, 27 limited community walkers were compared to 23 moderate-to-full community walkers. A significant larger proportion of limited community walkers were not confident about walking in the community compared to moderate-to-full community walkers (p = 0.042). Moreover mean cognitive response during two-minute-walk with dual task was 11.17 ± 3.62 for limited walkers and 13.48 ± 2.43 for moderate-to-full community walkers (p = 0.014). In contrast, moderate-to-full community walkers displayed relative larger reductions in walking distance as a result of dual task in comparison to limited community walkers (p = 0.068). Consequently, a randomized controlled trial was performed in 50 chronic stroke survivors to explore to what extent 10 weeks of treadmill training with concurrent cognitive distraction in comparison to 10 weeks of treadmill training with no distraction would change community walking ability. Stroke survivors who received dual task treadmill training showed larger increases in two-minute-walk distance compared to the control group from baseline to follow with an effect size r of 0.24 and a Cohen’s d of 0.50. Significant group and time interactions were seen for physical activity scale assessments favouring the dual task training group (p = 0.029). In addition, on a modified version of the University of Alabama study of Aging Life Space Assessment questionnaire, stroke survivors in the dual task training group scored 54.76 ± 26.64 compared to 41.53 ± 20.88 in the control group at follow-up, (p = 0.086). Both training groups improved on walking performance and endurance during training. Feasibility of dual task training was good, with only l0% drop out for intention to treat. The final part of this thesis focussed on results from fMRI and fNIRS measures that were taken to explore brain activation patterns during single and dual task gait before and after dual task training. At baseline, decreases in brain activation were seen in prefrontal cortex areas during dual task treadmill walking compared to single task treadmill walking. Moreover, fMRI during pedal movements with a concurrent cognitive task showed decreased brain activation compared to pedal movement alone. Dual task trained stroke survivors showed a reduction in right occipital cortex activation during pedalling at follow-up compared to baseline whereas control trained stroke survivors showed increases in this area from baseline to follow-up with a significant difference of activation change between groups (p < 0.001). In addition, stroke survivors who had received dual task training showed significant reductions in brain activation during pedalling and increase in activation during dual task pedalling from baseline to follow-up. The results from the comparisons between limited community walkers and moderate-to-full community walkers suggested that different coping strategies might apply after stroke depending on gait speed, but also indicated that both type of community walkers had difficulties with dual task walking. Dual task treadmill training showed good feasibility and positive effects on walking endurance and performance as well as training without distraction. There were trends suggesting that stroke survivors who were already physically active and had recovered their walking up to a certain standard were more likely to improve their dual task walking distance after dual training. Brain imaging measures showed decreases in activation from single to dual task locomotor movements which may relate to reduced dual task ability in stroke survivors, but these changes did not correlate with changes in behavioural measures of dual task. The changes in response to training may relate to plasticity and a recovery of the automaticity of control of normal walking as a result of dual task training. This thesis has provided novel research, insights and practical implications for dual task training after stroke. More research is needed, for instance to explore the extent to which stroke survivors could benefit from dual task training in more real-life situations. The use of neuroimaging tools in stroke rehabilitation trials helps to understand how motor control mechanisms change in response to training and could add to tailor rehabilitation to the individual’s need

Participative Urban Health and Healthy Aging in the Age of AI

This open access book constitutes the refereed proceedings of the 18th International Conference on String Processing and Information Retrieval, ICOST 2022, held in Paris, France, in June 2022. The 15 full papers and 10 short papers presented in this volume were carefully reviewed and selected from 33 submissions. They cover topics such as design, development, deployment, and evaluation of AI for health, smart urban environments, assistive technologies, chronic disease management, and coaching and health telematics systems

The effect of stress and alcohol on prefrontal cortex activity and cognitive performance in undergraduate students

Background: High stress exposure has been related to an increase in alcohol intake, and research has shown that both alcohol consumption and high stress levels affect brain function. Brain vulnerability to alcohol and stress is heightened during the development period, which in humans extends to the third decade of life. University students require a healthy brain for good academic performance, however, increased stress levels due to financial pressures, continuous academic demands, and student lifestyle may affect brain development and have detrimental consequences on cognitive performance. Aim: The research within this thesis aimed to investigate the effects of acute stress, perceived stress in the month prior, and average monthly units of alcohol consumption in the month prior on executive function and prefrontal cortex activity in undergraduate students aged between 18-30 years old. Methods: Three empirical studies were conducted. This comprised of two laboratory-based experiments including a pilot study (N=26) and a larger scale laboratory study (N=96), and finally an online study (N=88). These studies included measures of i) executive function (EF) under stress [Wisconsin Card Sort Task (WCST), Trail Making Task (TMT), Stroop Task, and Symbol Digit Modalities Task (SDMT)], ii) subjective stress and iii) perceived stress and average monthly units of alcohol consumption. In addition, both laboratory-based studies assessed brain activity during EF performance (using a functional near-infrared spectroscopy device), and the pilot study assessed physiological stress (electrodermal activity and heart rate) during exposure to acute stress. Results: The effects of both stress and alcohol appear to be domain and task-dependent. While stress induced immediately before EF performance (acute stress) increased EF performance in the Stroop task (response inhibition) the opposite effect was found for overall perceived stress experienced in the prior month. Interestingly, perceived stress (but not acute stress) improved performance in the TMT, a task related to cognitive flexibility but only in the online study. Despite the differential effect on EF performance, both acute and perceived stress increased activity in the prefrontal cortex during EF, specifically in the right dorsolateral prefrontal cortex. Unexpectedly, increased levels of average monthly units of alcohol consumption were related to increased performance in TMT A, Stroop B, and the SDMT in the laboratory study, while a similar increase in performance was found in TMT A in the online study. Furthermore, increased levels of average monthly units of alcohol consumption were related to increased activity in areas across the prefrontal cortex during the performance on some tasks such as Stroop B. Conclusion: The findings from this thesis conclude that stress and alcohol impact on domains of executive functioning are EF-task and EF-domain-dependent. Increases in prefrontal cortex activity due to exposure to stress and alcohol may indicate an increased neural effort to perform tasks under pressure, indicative of a compensatory mechanism to facilitate performance