Media layering, the simultaneous use of multiple unrelated media sources, has been documented as an increasing behavior trend (Roberts, Foehr, & Rideout, 2005) that marks a qualitative and quantitative difference in the way media is experienced. Presently, the impact on consumers from media layering is unknown. A strong theoretical foundation of human information processing theory predicts negative consequences in terms of performance cost in learning, and degradation of attention. Related research on dual task performance and multiple-channel processing demonstrates a decline in performance. This study compared sustained attention performance on a cancellation task, the d2 Test of Attention (Brickenkamp & Zillmer, 1998), in four varying media conditions. Performance scores were evaluated to determine the effect of degrees of extraneous media saturation and media interaction on attention task performance. / Ed. D.

The influence of levels of hostility on the lateralized tasks of verbal and nonverbal fluency, and the concurrent cerebral regulation of autonomic nervous system functioning was examined. Forty-eight right-handed males were recruited for participation with half classified as low-hostile and the other half as high-hostile. Previous research has shown that high-hostile males, at rest, have greater right hemisphere arousal relative to low-hostile males. It was predicted that this heightened, at rest, arousal would lead to reduced capacity to perform right hemisphere lateralized proximal tasks simultaneously. Two commonly used neuropsychological tests sensitive to left and right anterior cerebral systems are the Controlled Oral Word Association Test and the Ruff Figural Fluency Test (RFFT) respectively. Nonverbal fluency, verbal fluency, and perseverative errors were assessed using these measures. Cardiovascular measures of systolic and diastolic blood pressure, and heart rate were assessed using oscillometric technique with a digital blood pressure meter. A dual-task methodology was used to evaluate these anterior and posterior cerebral systems simultaneously. Since cardiovascular regulation and nonverbal fluency are both right-frontal tasks, it was predicted that high hostile men would evidence increased interference on cardiovascular regulation concurrent with the nonverbal fluency task in comparison with low hostile men. It was also predicted that high-hostile males would display more perseverative errors than low- hostile males on the nonverbal fluency task as a function of regulatory interference. The results supported a capacity-limited prediction in high-hostile males. High-hostile males evidenced significantly heightened systolic blood pressure responses during the nonverbal fluency task in comparison with low hostile males. Further, high-hostile males displayed more perseverative errors in nonverbal fluency than did the low-hostile males. No differences were found in the overall fluency scores (verbal or nonverbal). These results partially support the expectation that differences exist between high and low hostile males for right frontal functioning. Moreover, these differences manifest in multiple domains of associated right frontal functioning. These findings extend the evidence for the proposed anterior-posterior inhibition model of hostility. / Master of Science

No description available.

The aim of this study was to investigate the effect of irrelevant thoughts on golf performance.26 junior golfers participated in a repeated measures experiment where the effects ofirrelevant thoughts, through a working memory task, on golf performance was investigated.The participants got to hit 12 golf shots, 6 without working memory task and 6 with workingmemory task. A significant difference was found in both dependent variables lateral deviationand time. The participants had bigger lateral deviation and took longer time to complete theirshots when having a working memory task. The results from the study indicates thatirrelevant thoughts could impair junior golfers performance, although more research is neededon the subject for senior golfers. / Syftet med denna studie var att undersöka effekten av irrelevanta tankar på golfprestation. 26 juniorgolfare deltog i ett upprepat mätnings experiment där effekterna av irrelevanta tankar,genom ett arbetsminnestest, på golfprestation undersöktes. Deltagarna fick slå 12 golfslag, 6 utan arbetsminnestest och 6 med arbetsminnestest. En signifikant skillnad hittades i båda beroende variablerna spridning i sidled samt tid. Deltagarna hade större spridning och tog längre på sig att slå sina slag när de hade ett arbetsminnestest. Resultaten från studien indikerar att irrelevanta tankar kan försämra juniorgolfares prestation, däremot behövs vidareforskning kring ämnet för seniorgolfare.

BACKGROUND:Community ambulation is a highly complex skill requiring the ability to adapt to increased environmental complexity and perform multiple tasks simultaneously. After stroke, individuals demonstrate a diminished ability to perform dual-tasks. Current evidence suggests that conventional rehabilitation does not adequately address gait-related dual-task impairments after stroke, which may be contributing to low levels of participation and physical inactivity in community-dwelling stroke survivors. The objective of this study is to investigate the efficacy of dual-task gait training in community-dwelling adults within 1 year of stroke. Specifically, we will compare the effects of dual-task gait training and single-task gait training on cognitive-motor interference during walking at preferred speed and at fastest comfortable speed (Aim 1), locomotor control during obstacle negotiation (Aim 2), and spontaneous physical activity (Aim 3).METHODS/DESIGN:This single-blind randomized controlled trial will involve 44 individuals within 12 months of stroke. Following baseline evaluation, participants will be randomly allocated to single- or dual-task gait training. Both groups will receive 12, 30-minute sessions provided one-on-one over 4-6 weeks in an outpatient therapy setting. Single-task gait training involves practice of gait activities incorporating motor relearning principles. Dual-task gait training involves an identical gait training protocol / the critical difference being that the dual-task gait training group will practice the gait activities while simultaneously performing a cognitive task for 75% of the repetitions. Blinded assessors will measure outcomes at baseline, post-intervention, and 6 months after completion of the intervention. The primary outcome measure will be dual-task effects on gait speed and cognition during unobstructed walking. Secondary outcomes include spatiotemporal and kinetic gait parameters during unobstructed single- and dual-task walking at preferred and fastest comfortable walking speeds, gait parameters during high and low obstacle crossing, spontaneous physical activity, executive function, lower extremity motor function, Timed Up and Go, balance self-efficacy, number of falls, and stroke-related disability. Hypotheses for each aim will be tested using an intention-to-treat analysis with repeated measures ANOVA design.DISCUSSION:This trial will provide evidence to help clinicians make decisions about the types of activities to include in rehabilitation to improve dual-task walking after stroke.TRIAL REGISTRATION:ClinicalTrials.gov NCT01568957

The effects that cellular (cell) phone conversation may have on pedestrian road-crossing performance is unknown. A series of experiments was conducted using a virtual reality road crossing simulator to examine this issue. The participants were primarily university students aged between 18 and 24 years old, although one study compared a group aged 18 to 24 to a group between 50 and 67 years old. Two experimental situations were used: a gap-choice situation, in which the participants had to choose a gap to cross through; and an infrequency situation, where vehicles were present on only 10% of the trials. Participants were impaired by a simulated phone conversation task when compared to no-conversation task, as evidenced by longer reaction times, slower walking speeds, poorer gap choices, and more cautious behaviours. Most importantly, conversation was related to a decrease in the mean margins of safety, and the participants were hit or nearly hit by vehicles more often when talking. The general performance of the older participants did not differ from that of the younger participants, and both groups were impaired to a similar extent by the conversation task. Participants were found to use irrelevant distance information to inform their gap-choice decisions, a strategy associated with a decrease in safety as the distance between the vehicles increased. It was also found that their use of time-to-arrival information was impaired when engaged in the conversation task. Overall, talking on a cell phone while crossing a road may represent an unnecessary increase in risk; therefore, care should be taken if these two acts are being conducted concurrently.

As an extension of previous studies (Urbanczyk, Angel, & Kennelly, 1988) examining the effects of unimanual finger tapping on lateralized cognitive tasks, lateral body orienting was added to an established dual task paradigm to generate differential hemispheric activation and shifts of attention. One hundred twenty university students retained sequences of digits or spatial locations for 20 seconds either alone or during finger tapping. By turning both head and eyes left or right, the hemisphere congruent with the sequences (LH for digits, RH for locations) or incongruent (vice versa) was activated. Activation had little effect on retention means but greatly affected resource composition supporting task performance. Congruent orientation produced significantly higher positive correlations between digit and location tasks than incongruent orientation. Females showed higher sequence retention correlations than males across both orienting groups. For females, congruent activation enhanced tapping rates and retention-tapping correlations. For males, activation affected neither of these. Discussed in light of neuroanatomical research, these results suggest that congruent attentional orienting may integrate regions of the less activated hemisphere into networks of the more activated hemisphere. This unification may occur more readily across the female corpus callosum, producing a greater dependence upon a general attentional resource than for males, who appear to depend more upon hemispheric resources.

Pouco se conhece ainda sobre as demandas atencionais necessárias para o equilíbrio em condições desafiantes, como em situação de postura perturbada. Respostas posturais podem ser influenciadas por tarefas supraposturais. Tarefas de estabilidade manual parecem induzir respostas posturais mais eficientes. Já as tarefas supraposturais cognitivas apresentam resultados incongruentes nos efeitos em tarefa postural perturbada. Este estudo procurou determinar os efeitos de realizar diferentes tipos de tarefa suprapostural nas respostas posturais reativas a uma perturbação mecânica. Vinte e cinco adultos jovens foram sujeitos a uma perturbação mecânica, com liberação de carga, imprevisível. Concomitantemente com essa tarefa postural, realizaram uma tarefa de estabilidade manual, que requeria segurar uma bandeja com cilindro, em uma de duas variantes: com superfície plana para baixo, ou com superfície redonda para baixo. Os participantes realizaram ainda uma tarefa cognitiva, de contagem decrescente de três em três. Essa tarefa foi desempenhada em conjunto com a tarefa dual descrita anteriormente e ainda de forma isolada. A realização da multitarefa prejudicou o desempenho na tarefa cognitiva e também na tarefa postural. Foi observado maior número de erros e maior tempo médio para responder à tarefa cognitiva. Na tarefa postural foram encontradas diferenças nas estratégias motoras quando foi solicitada a tarefa cognitiva: maiores amplitudes de flexão articular no quadril e ombro, maior deslocamento linear do tronco, maior velocidade do tronco e da bandeja bem como menor magnitude do gastrocnêmio. Nesta condição os participantes também demoraram mais para reverter a oscilação anterior e assim retornar a uma posição mais estável. Assim a integração entre as tarefas não foi bem sucedida, por interferência nos processos e/ou recursos atencionais necessários para realizar as tarefas. É possível que tenha ocorrido afastamento de recursos atencionais do processamento de inputs sensoriais associados ao controle postural. Tal afetaria o central set, produzindo uma influência imprecisa nas respostas posturais à perturbação. A tarefa manual produziu efeito positivo na tarefa postural. Observou-se que a condição de maior restrição da tarefa manual induziu uma resposta postural mais eficiente, com menor amplitude articular do ombro, quadril e tornozelo. Verificou-se ainda que as medidas referentes à mobilização do tronco: amplitude linear, velocidade e verticalidade, bem como a velocidade da bandeja, também foram menores. Este estudo indica que o central set é elaborado a partir de restrições funcionais impostas por tarefas supra-posturais e consegue exercer algum controle na tarefa postural, mesmo com um processamento paralelo para realizar uma tarefa cognitiva. A competição entre os processos e\\ou recursos para realizar as tarefas propostas no presente estudo afeta o equilíbrio, de forma negativa quando uma tarefa cognitiva está presente, e de forma positiva quando existe uma restrição funcional manual / Attentional demands on posture challenging conditions still present many questions. Postural answers can be influenced by suprapostural tasks. Motor tasks and, specifically, manual stability tasks induce more efficient postural answers. Cognitive suprapostural tasks present incongruent effects on perturbed posture. This study aimed to determine the effects of performing different suprapostural task types on reactive postural answers. Twenty five received a mechanical perturbation through unpedictable load liberation. Concurrently to this postural task, they performed a manual stability task, to hold a cylinder on a tray, with two variations: with the flat surface down or with the round surface down. Participants also performed a cognitive task, the n-back 3 task. This task was performed as a single task and concomitantly with the dual task. Performing multitask impaired cognitive and postural task performance. More errors and greater mean time to answer to the cognitive task were observed. At the postural task we found differences on motor strategies on the cognitive task condition: greater joint flexion at hip and shoulder, greater trunk linear displacement, greater trunk and tray velocity, as well as a reduction on gastrocnemius magnitude. At this condition we also found that the participants took longer to revert the anterior oscilation to return to a more stable position. Therefore the integration between tasks was successful, given the interference between the attentional processes and/or necessary resources to accomplish the tasks. It is possible that may have been withdrawal of attentional resources form the sensorial inputs processing associated with the postural control. That would affect central set, producing an inaccurate influence on postural answers to perturbation. Manual task produced positive effect on postural task. On the higher restriction condition it was found a more efficient postural answer, with less joint range on shoulder, hip and ankle. Additionally, the trunk variables: linear displacement, velocity and verticality, as well as tray velocity, also were inferior. This study indicates that central set is elaborated based on functional restrictions imposed by suprapostural tasks and it can influence postural task, even with a parallel processing in order to execute a concomitant cognitive task. Competition between processes and/or resources to accomplish the proposed tasks affects balance, with negative results when a cognitive task is present, and with positive results when there is a manual restriction

In vier Laborexperimenten wurde versucht, auf der Grundlage der Theorie multipler Ressourcen visuelle und kognitive Ablenkung bei der Kraftfahrzeugführung getrennt zu erfassen. Um die Vorhersagen der Theorie prüfen zu können, sind die zu erwartenden Ablenkungseffekte zuvor mit Hilfe des Computational Model of Task Interference geschätzt worden. Die Experimente 1 und 2 wurden als einfache, visuell ablenkende Reaktionsaufgaben an einem PC realisiert, bei denen die Versuchspersonen unter visueller und unter kognitiver Ablenkung auf den Wechsel von Verkehrszeichen reagierten. Entgegen der Hypothese wurde in Versuch 1 die Reaktionsleistung in der Primäraufgabe durch visuelle Ablenkung nicht stärker beeinträchtigt als durch kognitive Ablenkung. Die Wiederholung des Experiments mit überarbeiteten Aufgaben ergab in Versuch 2 eine hypothesenkonforme Trennung zwischen visueller und kognitiver Ablenkung. Die Experimente 3 und 4 bestanden aus einer kognitiv beanspruchenden Navigationsaufgabe, die ebenfalls an einem PC unter visueller und kognitiver Ablenkung vollzogen wurde. Die Navigationsaufgabe zeichnete sich dadurch aus, dass visuelle und motorische Störeinflüsse der ablenkenden Zweitaufgaben zum Messzeitpunkt ausgeblendet wurden, um ausschließlich kognitive Interferenzen zu erheben. Weder im dritten Versuch noch in Versuch 4 mit einer zeitlichen Zuspitzung der Navigationsaufgabe konnte gezeigt werden, dass kognitive Ablenkung eine kognitiv beanspruchende Navigationsaufgabe stärker beeinträchtigt als visuelle Ablenkung. Die anderslautende Interferenzvorhersage des Computational Model of Task Interference hat sich nicht bestätigt. Die Ergebnisse dieser Arbeit legen nahe, dass visuelle und kognitive Ablenkung nicht als getrennt messbare Phänomene aufgefasst werden können. Einer dementsprechenden Auslegung der Theorie multipler Ressourcen muss für den hier gewählten experimentellen Zugang der Ablenkungsmessung widersprochen werden. / Based on multiple resource theory, four laboratory experiments were undertaken in an effort to independently measure visual and cognitive distractions during motor vehicle operation. In order to verify the predictions of the theory, the expected distraction effects were previously assessed with the aid of the computational model of task interference. Experiments 1 and 2 were performed as simple, visually distracting reaction tasks at a computer workstation, during which the test persons reacted to changing traffic signs while being subjected to visual and cognitive distractions. Contrary to the hypothesis, during experiment 1, the reaction performance in the primary task was not impaired more severely through visual distraction than through cognitive distraction. Repetition of the experiment with modified tasks in experiment 2 revealed a hypothesis-confirming separation between visual and cognitive distractions. Experiments 3 and 4 consisted of a cognitively challenging navigation task, which was also performed at a computer workstation with the interference of visual and cognitive distractions. During the navigation task, the visual and motor interferences of the distracting secondary tasks were omitted at the time of measurement in order to record only the cognitive interferences. Neither during the third experiment, nor during experiment 4, which involved an added time-pressure element to the navigation task, was it possible to demonstrate that cognitive distraction impairs a cognitively challenging navigation task to a greater extent than a visual distraction. The contrary interference prediction of the computational model of task interference was not confirmed. The results of this study suggest that visual and cognitive distractions cannot be regarded as separately measurable phenomena. A corresponding interpretation of multiple resource theory must therefore be rejected for the experimental approach selected here with regard to distraction measurement.

Neste estudo foi avaliado o efeito da restrição de estabilidade imposta por uma tarefa voluntária sobre a adaptação de respostas posturais reativas a perturbações externas em jovens, idosos sadios e idosos com doença de Parkinson (DP). No Experimento 1 participantes com DP e idosos sadios foram perturbados por meio de translação posterior da superfície de apoio, enquanto executavam duas versões de uma tarefa voluntária: segurando uma bandeja com um cilindro apoiado em sua base (BR) ou em seu lado circular (AR). A avaliação foi feita por meio de blocos alternados de baixa e alta restrição. Os resultados indicaram que ambos os grupos mostram menor velocidade da bandeja no contexto de AR em comparação ao de BR. A latência de resposta postural foi maior no contexto de AR apenas para indivíduos sadios. Indivíduos sadios apresentaram diferentes padrões de coordenação ombro-quadril em função da restrição da tarefa, enquanto idosos com DP apresentaram um padrão relativamente invariável. Estes resultados sugerem que a doença de Parkinson prejudica a capacidade de adaptar as respostas posturais às exigências impostas por uma tarefa voluntária. O Experimento 2 teve como objetivo comparar as respostas posturais reativas entre jovens e idosos sadios. O mesmo paradigma do Experimento 1, com exceção do tipo de perturbação, foi utilizado no Experimento 2. Ambos os grupos diminuíram a velocidade da bandeja no contexto de AR em comparação ao contexto de BR. Os resultados mais expressivos mostraram que, enquanto os jovens adaptaram a latência muscular, magnitude muscular, nível de coativação muscular e coordenação interarticular de acordo com a sequência, os idosos foram mais sensíveis ao contexto atual de restrição da tarefa voluntária. Estes resultados sugerem que o envelhecimento leva à mudança de uma adaptação mais generalizada para uma mais específica das respostas posturais reativas / This study assessed the effect of stability constraints imposed by a voluntary task on the adaptation of postural responses to an external perturbation in healthy adults and in elderly individuals with Parkinsons disease (PD). In Experiment 1 subjects with PD and age-matched controls were perturbed through a backward translation of the support surface while standing and performing two versions of a voluntary task: holding a tray with a cylinder placed with the flat side down (LC) or with the rolling round side down (HC). Participants performed alternating blocks of low and high constraint trials. Parkinsons disease participants accomplished the voluntary task as well as controls, showing slower tray velocity in the high, as compared with the low, constraint context. Latency of postural responses was longer in the high constraint context only for control subjects. Control subjects presented different patterns of hip-shoulder coordination as a function of task constraint, whereas PD subjects had a relatively invariable pattern. These results suggest that Parkinsons disease impairs the capacity to adapt postural responses to constraints imposed by a voluntary task. Experiment 2 aimed at comparing postural reactive responses between healthy young and elderly individuals in response to unexpected load release. Results showed that while the young group adapted muscular latency, muscular magnitude, coactivation level and interjoint coordination according to task-constraint sequence, the elderly group was more sensitive to the current context of voluntary task constraint. These results suggest that aging lead to more specific postural reactive responses adaptation