Doctor of Philosophy (Medicine) / Sleepiness is an important source of morbidity in the community, with potentially catastrophic consequences of occupational or driving injuries or accidents. Although many measures of sleepiness exist, there is no gold standard. The electroencephalograph (EEG) has been studied as an indicator of sleep pressure in the waking organism, or sleep depth. A mathematical model has been developed, relating the observed EEG to interactions between groups of neurons in the cortex and thalamus (Robinson, Rennie, Rowe, O'Connor, & Gordon, 2005; Robinson, Rennie, & Wright, 1997). These interactions are thought to be important in the transition from wake to sleep. Sleepiness is common in obstructive sleep apnea (OSA). The measurement of sleepiness would have great utility in quantifying the disease burden, measuring treatment response, or determining fitness for work or driving. This study will evaluate parameters derived from the EEG mathematical model as a measure of sleepiness. It is divided into the following four parts: 1. Subjects with likely OSA based on symptoms and demographics from an international database were compared with matched non-OSA controls. The OSA group showed deficits in executive function and abnormalities on evoked response potential testing. 2. Outcomes from a cross-sectional study in a sleep-clinic OSA population were aggregated by factor analysis into a five summary variables relevant to sleepiness: subjective sleepiness, mood & anxiety, memory & learning, driving, and executive functioning. 3. EEG mathematical model parameters from wake EEG recordings were related to the five summary outcomes. Executive function correlated with a parameter Z, representing the negative feedback loop between the thalamic reticular nucleus and the thalamocortical relay nuclei. 4. EEG model parameters during first NREM sleep cycle of 8 subjects with regular sleep architecture were studied. Net cortical excitation (parameter X) is predicted to increase across the cycle, while there was, as predicted, a greater inhibitory effect of the thalamic reticular nucleus upon thalamocortical relay cells (parameter Z). In this preliminary assessment, EEG model parameters reflecting thalamocortical interactions are sensitive to prefrontal lobe tasks such as executive function, which are known to be vulnerable to sleep loss and sleepiness, and these parameters also show variation with increasing sleep depth.

Doctor of Philosophy (Medicine) / Sleepiness is an important source of morbidity in the community, with potentially catastrophic consequences of occupational or driving injuries or accidents. Although many measures of sleepiness exist, there is no gold standard. The electroencephalograph (EEG) has been studied as an indicator of sleep pressure in the waking organism, or sleep depth. A mathematical model has been developed, relating the observed EEG to interactions between groups of neurons in the cortex and thalamus (Robinson, Rennie, Rowe, O'Connor, & Gordon, 2005; Robinson, Rennie, & Wright, 1997). These interactions are thought to be important in the transition from wake to sleep. Sleepiness is common in obstructive sleep apnea (OSA). The measurement of sleepiness would have great utility in quantifying the disease burden, measuring treatment response, or determining fitness for work or driving. This study will evaluate parameters derived from the EEG mathematical model as a measure of sleepiness. It is divided into the following four parts: 1. Subjects with likely OSA based on symptoms and demographics from an international database were compared with matched non-OSA controls. The OSA group showed deficits in executive function and abnormalities on evoked response potential testing. 2. Outcomes from a cross-sectional study in a sleep-clinic OSA population were aggregated by factor analysis into a five summary variables relevant to sleepiness: subjective sleepiness, mood & anxiety, memory & learning, driving, and executive functioning. 3. EEG mathematical model parameters from wake EEG recordings were related to the five summary outcomes. Executive function correlated with a parameter Z, representing the negative feedback loop between the thalamic reticular nucleus and the thalamocortical relay nuclei. 4. EEG model parameters during first NREM sleep cycle of 8 subjects with regular sleep architecture were studied. Net cortical excitation (parameter X) is predicted to increase across the cycle, while there was, as predicted, a greater inhibitory effect of the thalamic reticular nucleus upon thalamocortical relay cells (parameter Z). In this preliminary assessment, EEG model parameters reflecting thalamocortical interactions are sensitive to prefrontal lobe tasks such as executive function, which are known to be vulnerable to sleep loss and sleepiness, and these parameters also show variation with increasing sleep depth.

Objective: To extend previous research designs and examine cognitive performance up to 30 days postconcussion. Method: A prospective cohort design was used to examine 2000 athletes from 8 mid-Michigan area high schools to compare baseline neurocognitive performance with postconcussion neurocognitive performance. All concussed athletes were readministered the Immediate Post Assessment and Cognitive Test (ImPACT) at 2, 7, 14, 21, and 30 days postconcussion. Results: A total of 72 high school athletes (aged 15.8 ± 1.34 years) sustained a concussion. A significant within-subjects effect for reaction time (F = 10.01; P= 0.000), verbal memory (F = 3.05; P = 0.012), motor processing speed (F= 18.51; P = 0.000), and total symptoms following an injury (F= 16.45; P= 0.000) was found. Concussed athletes demonstrated a significant decrease in reaction time up to 14 days postconcussion (P = 0.001) compared with baseline reaction time. Reaction time returned to baseline levels at 21 days postinjury (P = 0.25). At 7 days postinjury, impairments in verbal memory (P= 0.003) and motor processing speed (P= 0.000) were documented and returned to baseline levels by 14 days postinjury. Concussed athletes self-reported significantly more symptoms at 2 days postconcussion (P = 0.000) and exhibited a resolution of symptoms by 7 days postinjury (P = 0.06). Conclusion: High school athletes could take up to 21 days to return to baseline levels for reaction time. These data support current recommendations for the conservative management of concussion in the high school athlete.

No description available.

Observa-se um desempenho cognitivo abaixo da média na população obesa. A cirurgia bariátrica e a consequente perda de tecido adiposo parecem ter efeitos positivos sobre o funcionamento cognitivo. Objetivo: Avaliar o desempenho cognitivo e o estado nutricional do paciente pré e pós cirurgia bariátrica Metodologia: Foram incluídos 22 pacientes do ambulatório de Cirurgia Bariátrica do HCFMRP-USP, que foram submetidos à avaliação neuropsicológica composta de testes psicológicos de atenção, memória e velocidade de processamento de informação em dois momentos: período pré-cirúrgico (1 a 2 dias antes da cirurgia bariátrica) e pós cirúrgico (de 6 a 12 meses). A avaliação do estado nutricional foi feita a partir de exames coletados rotineiramente pela equipe, em períodos pré e pós-cirúrgico. Os dados obtidos foram comparados entre os períodos pré e pós e analisados estatisticamente. Resultados: A perda de excesso de tecido adiposo e a melhora no estado nutricional do paciente foi acompanhada de uma melhora no desempenho cognitivo. Observouse melhora no desempenho da atenção para o cartão 2 do teste Stroop e da velocidade de processamento para os subtestes Códigos e Procurando Símbolos no teste WAIS. Houve redução de ferritina, gama GT, ácido úrico, proteínas totais e triglicérideos e aumento de ácido fólico sérico, volume corpuscular médio, HDL. Conclusão: Este estudo sugere que a cirurgia bariátrica tem como efeito a melhora no desempenho cognitivo. Observam-se alguns indícios de que a diminuição dos marcadores de processo inflamatório pode estar correlacionada com a melhora cognitiva dos pacientes. A melhora do desempenho, no entanto, não foi suficiente para atingir a média da população. O estado nutricional, apesar de ter sofrido alterações, foi considerado estável clinicamente / It was observed that the obese population is more likely to present cognitive impairment. Bariatric surgery and its consequently lost of adipose tissue seems like to have positive effects in cognitive performance. Objective: Evaluate the patient´s cognitive performance and his nutritional aspects before and after bariatric surgery. Methodology: 22 patients from Bariatric Surgery Service HCFMRP-SP were included. The neuropsychological evaluation was composed by psychological tests (attention, memory and information processing), and it was applied in two moments: preoperative (1-2 days before surgery) and pos surgery (6-12 months). The exams for the nutritional assessment were collected before and after bariatric surgery. The data were compared and analyzed. Results: Cognitive improvment in attention was observed in card 2 Stroop test and in information processing in the subtests Coding and Simbol Searching, from WAIS test. There was a reduction in ferritin, GT Gama, uric acid, total proteins and triglycerides and increase in serum folic acid, mean corpuscular volume, HDL. Conclusão: Bariatric surgery improve cognitive performance. Increase in inflamatory markers may be relates with cognitve improvment. However, the group did\'nt reach médium average after bariatri surgery. The group was considered clinically stable for the nutritional changes

Acute aerobic exercise exerts a small beneficial effect on cognition. Much of the research to date has focused on cognitive changes following a bout of exercise, while little is currently known about changes in cognitive performance during exercise. The limited research that has been conducted suggests either positive, negative, or no effects on cognitive performance during exercise. Thus, the primary purpose of this study was to examine the effects of low-intensity cycling on cognitive function in college-aged students, indexed by response accuracy, reaction time, P3 amplitude, and P3 latency. Twenty-seven (Mage = 22.9 ± 3.0 years old) college-aged individuals were counterbalanced into low-intensity exercise (EX) and seated control (SC) conditions. During each condition, participants completed a 10-minute resting baseline period, 20 minutes of either sustained cycling or seated rest, and a 20-minute recovery period. Primary outcomes were assessed at 10-minute intervals (5 blocks total) throughout each condition via a modified oddball task. Across time blocks, both conditions exhibited faster reaction times on frequent trials but reduced accuracy to rare trials, suggesting a speed-accuracy tradeoff. There were no differences between conditions in P3 latency whereas a significant reduction in P3 amplitude was observed during the 20-minute exercise period compared to the control condition. Taken together, the results suggest that exercise at lower doses may have minimal influence on behavioral outcomes of cognitive performance but may impact more basic measures of brain function. Information gathered from this study may aid in the development of appropriate exercise prescriptions for populations looking to specifically target cognitive function deficits.

Introduction: Many studies have found an association between Toxoplasma gondii seropositivity and behavioral and cognitive changes in animal models and in humans. In addition, early findings have suggested an association between T. gondii seropositivity and Alzheimer's disease (AD). We sought to determine whether there is an association between T. gondii seropositivity and AD as well as cognitive functioning (including memory, working memory, processing speed, language functioning, executive functioning) in a large, well-characterized sample of subjects with AD and matched controls without dementia. Method: Using ELISA assays, we determined anti-T. gondii IgG antibody titers in 114 control subjects and in 105 subjects diagnosed with AD through an Alzheimer's Disease Research Center. We compared the seroprevalence between the two groups using propensity score matching (PSM). We also compared associations between T. gondii seropositivity and cognitive functioning using both PSM and linear regressions. Results: We found no differences between groups in age, ethnicity, or gender. Education and socioeconomic status was slightly higher in the control group. Using PSM, we did not find a significant difference in having AD due to T. gondii seropositivity between the two groups. Using PSM, we found T. gondii seropositivity was associated with worse performance on the WAIS-R Digit Symbol test. Within the AD group, we found T. gondii seropositivity was associated with worse performance on the WAIS Block Design and Trail Making B tests. Conclusion: In this sample, we found no evidence of an association between T. gondii seropositivity and AD in a larger study than previous studies. We found evidence of a negative association between processing speed and T. gondii seropositivity as well as a negative association between processing speed, executive functioning, and T. gondii seropositivity in those with AD.

Introduction: Many studies have found an association between Toxoplasma gondii seropositivity and behavioral and cognitive changes in animal models and in humans. In addition, early findings have suggested an association between T. gondii seropositivity and Alzheimer's disease (AD). We sought to determine whether there is an association between T. gondii seropositivity and AD as well as cognitive functioning (including memory, working memory, processing speed, language functioning, executive functioning) in a large, well-characterized sample of subjects with AD and matched controls without dementia. Method: Using ELISA assays, we determined anti-T. gondii IgG antibody titers in 114 control subjects and in 105 subjects diagnosed with AD through an Alzheimer's Disease Research Center. We compared the seroprevalence between the two groups using propensity score matching (PSM). We also compared associations between T. gondii seropositivity and cognitive functioning using both PSM and linear regressions. Results: We found no differences between groups in age, ethnicity, or gender. Education and socioeconomic status was slightly higher in the control group. Using PSM, we did not find a significant difference in having AD due to T. gondii seropositivity between the two groups. Using PSM, we found T. gondii seropositivity was associated with worse performance on the WAIS-R Digit Symbol test. Within the AD group, we found T. gondii seropositivity was associated with worse performance on the WAIS Block Design and Trail Making B tests. Conclusion: In this sample, we found no evidence of an association between T. gondii seropositivity and AD in a larger study than previous studies. We found evidence of a negative association between processing speed and T. gondii seropositivity as well as a negative association between processing speed, executive functioning, and T. gondii seropositivity in those with AD.

Thomas G. Brown, Ph.D., co-directeur de recherche / Objectifs : La capacité en matière de prise de décisions des récidivistes de conduite avec capacités affaiblies (CCA) semble les distinguer des non-contrevenants, particulièrement dans des situations ambiguës à haut risque, telles que la CCA. Cette étude exploratoire vise à vérifier l’hypothèse selon laquelle les récidivistes de CCA (R) auraient une moins bonne capacité de prise de décisions et une plus faible réponse de conductibilité électrodermale par anticipation à la tâche Iowa Gambling Task (IGT) que les non-contrevenants (C). Méthode : Vingt-trois récidivistes et 24 non-contrevenants ont été recrutés. Leur âge moyen (± É.T.) était 44.17(10.03) et 37.29 (10.60) ans respectivement. Les participants devaient être âgés de 18 ans ou plus, et avoir eu deux condamnations pour CCA ou plus pour le groupe R, et zéro CCA et un permis de conduire pour le groupe C. Les participants ont effectué I’IGT, une tâche neurocognitive de prise de décisions comprenant 100 sélections de cartes divisées en cinq blocs pour les analyses. On a comparé la performance du groupe R versus le groupe C à l’aide d’une ANOVA à mesures répétées [2 (groupe) x 5 (blocs)]. On a évalué la performance durant les blocs 1 & 2 (décisions dans l’ambiguïté) et blocs 3-5 (décisions sous haut risque) en utilisant des tests t post-hoc. Finalement, on a mesuré leur réponse de conductibilité électrodermale (RCEA) durant l’IGT. Résultats : L’ANOVA à mesures répétées des blocs 1 à 5 a révélé un effet significatif de l’interaction groupe par bloc, F(1,45)=5.28, p=.03, état carré =.11. Les tests t post hoc ont révélé une différence significative entre les groupes pour la combinaison des blocs 3 à 5, t(45) = 3.38, p = .002. Un effet d’interaction significatif a été détecté pour la RCEA des récidivistes de CCA versus celle des non-contrevenants, F(8,160)=2.33, p=.02, état carré =.10. Conclusion : Les récidivistes de CCA performent moins bien que les non-contrevenants à l’IGT. Ils persistent à prendre des décisions basées sur le potentiel de gains immédiats et négligent donc les risques de pertes. Ceci suggère qu’ils ont des déficits en matière de prise de décision, ce qui, en tant que groupe, les différencie des non-contrevenants. Une difficulté en matière de prise de décisions pourrait expliquer en partie le comportement impulsif fréquemment associé au récidivisme de CCA. Finalement, puisque les analyses de RCEA manquaient de puissance statistique, il est possible que de plus grands échantillons puissent permettre d’observer des différences entre les groupes de participants dans l’analyse de RCEA. / Objectives: Poor decision making in ambiguous high-risk situations, such as driving while impaired (DWI) by alcohol, may differentiate DWI recidivists from non-offenders. In this study, we test the hypothesis that DWI recidivists (R) will exhibit poorer decision-making performance on the Iowa Gambling Task (IGT), and in line with the Somatic Marker Hypothesis, weaker anticipatory somatic activation (using skin conductance response as index) than non-offenders (C, comparison group). Methods: DWI recidivists and non-DWI control drivers were recruited, [R (n=23) and C (n=24), mean ages (± SD) 44.17(10.03) and 37.29 (10.60) years respectively]. Participant selection criteria included ≥ 18 years old and ≥2 DWI convictions for group R and 0 DWI convictions lifetime and a driver’s license for group C. The participants performed the IGT, a decision-making neurocognitive task containing 100 card selection trials that we divided into 5 blocks for analyses. A 2 (group) x 5 (blocks) repeated measures ANOVA was used to compare group R performance on the IGT versus group C, followed by post hoc independent t-tests on aggregated blocks 1-2 (decision under ambiguity) & 3-5 (decision under high risk) to identify the source of group X block significant interactions. Two 3 (group) x 5 (blocks) repeated measures ANOVAs (for good decks and for bad decks) were used to compare the aSCR of groups C and R. Results: ANOVA repeated measures on blocks 1 to 5 produced a significant effect of group by block interaction F(1,45)=5.28, p=.03, partial ƞ2 =.11. Post hoc t-tests on aggregated blocks 3 to 5 were statistically significant, t(45) = 3.38, p = .002. A significant group x block interaction effect was found for good decks aSCR, F(8,160)=2.33, p=.02, partial ƞ2 =.10 . Conclusion: DWI recidivists performed more poorly than controls on the IGT, persistently making decisions based on potential immediate gains and neglecting associated loss risks and long-term outcome. This suggests they have reduced neurocognitive decision-making capacities distinguishable from the general population. While DWI recidivists’ behaviour appears as impulsive, these results suggest that their behaviour pattern involves decision-making difficulties. Larger sample sizes may be needed to detect a between-group effect in the aSCR analyses, as they were considerably underpowered.

Objectifs : La capacité en matière de prise de décisions des récidivistes de conduite avec capacités affaiblies (CCA) semble les distinguer des non-contrevenants, particulièrement dans des situations ambiguës à haut risque, telles que la CCA. Cette étude exploratoire vise à vérifier l’hypothèse selon laquelle les récidivistes de CCA (R) auraient une moins bonne capacité de prise de décisions et une plus faible réponse de conductibilité électrodermale par anticipation à la tâche Iowa Gambling Task (IGT) que les non-contrevenants (C). Méthode : Vingt-trois récidivistes et 24 non-contrevenants ont été recrutés. Leur âge moyen (± É.T.) était 44.17(10.03) et 37.29 (10.60) ans respectivement. Les participants devaient être âgés de 18 ans ou plus, et avoir eu deux condamnations pour CCA ou plus pour le groupe R, et zéro CCA et un permis de conduire pour le groupe C. Les participants ont effectué I’IGT, une tâche neurocognitive de prise de décisions comprenant 100 sélections de cartes divisées en cinq blocs pour les analyses. On a comparé la performance du groupe R versus le groupe C à l’aide d’une ANOVA à mesures répétées [2 (groupe) x 5 (blocs)]. On a évalué la performance durant les blocs 1 & 2 (décisions dans l’ambiguïté) et blocs 3-5 (décisions sous haut risque) en utilisant des tests t post-hoc. Finalement, on a mesuré leur réponse de conductibilité électrodermale (RCEA) durant l’IGT. Résultats : L’ANOVA à mesures répétées des blocs 1 à 5 a révélé un effet significatif de l’interaction groupe par bloc, F(1,45)=5.28, p=.03, état carré =.11. Les tests t post hoc ont révélé une différence significative entre les groupes pour la combinaison des blocs 3 à 5, t(45) = 3.38, p = .002. Un effet d’interaction significatif a été détecté pour la RCEA des récidivistes de CCA versus celle des non-contrevenants, F(8,160)=2.33, p=.02, état carré =.10. Conclusion : Les récidivistes de CCA performent moins bien que les non-contrevenants à l’IGT. Ils persistent à prendre des décisions basées sur le potentiel de gains immédiats et négligent donc les risques de pertes. Ceci suggère qu’ils ont des déficits en matière de prise de décision, ce qui, en tant que groupe, les différencie des non-contrevenants. Une difficulté en matière de prise de décisions pourrait expliquer en partie le comportement impulsif fréquemment associé au récidivisme de CCA. Finalement, puisque les analyses de RCEA manquaient de puissance statistique, il est possible que de plus grands échantillons puissent permettre d’observer des différences entre les groupes de participants dans l’analyse de RCEA. / Objectives: Poor decision making in ambiguous high-risk situations, such as driving while impaired (DWI) by alcohol, may differentiate DWI recidivists from non-offenders. In this study, we test the hypothesis that DWI recidivists (R) will exhibit poorer decision-making performance on the Iowa Gambling Task (IGT), and in line with the Somatic Marker Hypothesis, weaker anticipatory somatic activation (using skin conductance response as index) than non-offenders (C, comparison group). Methods: DWI recidivists and non-DWI control drivers were recruited, [R (n=23) and C (n=24), mean ages (± SD) 44.17(10.03) and 37.29 (10.60) years respectively]. Participant selection criteria included ≥ 18 years old and ≥2 DWI convictions for group R and 0 DWI convictions lifetime and a driver’s license for group C. The participants performed the IGT, a decision-making neurocognitive task containing 100 card selection trials that we divided into 5 blocks for analyses. A 2 (group) x 5 (blocks) repeated measures ANOVA was used to compare group R performance on the IGT versus group C, followed by post hoc independent t-tests on aggregated blocks 1-2 (decision under ambiguity) & 3-5 (decision under high risk) to identify the source of group X block significant interactions. Two 3 (group) x 5 (blocks) repeated measures ANOVAs (for good decks and for bad decks) were used to compare the aSCR of groups C and R. Results: ANOVA repeated measures on blocks 1 to 5 produced a significant effect of group by block interaction F(1,45)=5.28, p=.03, partial ƞ2 =.11. Post hoc t-tests on aggregated blocks 3 to 5 were statistically significant, t(45) = 3.38, p = .002. A significant group x block interaction effect was found for good decks aSCR, F(8,160)=2.33, p=.02, partial ƞ2 =.10 . Conclusion: DWI recidivists performed more poorly than controls on the IGT, persistently making decisions based on potential immediate gains and neglecting associated loss risks and long-term outcome. This suggests they have reduced neurocognitive decision-making capacities distinguishable from the general population. While DWI recidivists’ behaviour appears as impulsive, these results suggest that their behaviour pattern involves decision-making difficulties. Larger sample sizes may be needed to detect a between-group effect in the aSCR analyses, as they were considerably underpowered. / Thomas G. Brown, Ph.D., co-directeur de recherche