Modelado y Evaluación de Entornos Virtuales Interactivos para Rehabilitación Cognitiva en Daño Cerebral

El Daño Cerebral (DC) se refiere a cualquier lesión producida en el cerebro y que afecta a su funcionalidad. Se ha convertido en una de las principales causas de discapacidad neurológica de las sociedades desarrolladas. Hasta la más sencilla de las actividades y acciones que realizamos en nuestro día a día involucran a los procesos cognitivos. Por ello, la alteración de las funciones cognitivas como consecuencia del DC, limita no sólo la calidad de vida del paciente sino también la de las persona de su entorno. La rehabilitación cognitiva trata de aumentar la autonomía y calidad de vida del paciente minimizando o compensando los desórdenes funciones causados por el episodio de DC. La plasticidad cerebral es una propiedad intrínseca al sistema nervioso humano por la que en función a la experiencia se crean nuevos patrones de conectividad. El propósito de la neurorrehabilitación es precisamente modular esta propiedad intrínseca a partir de ejercicios específicos, los cuales podrían derivar en la recuperación parcial o total de las funciones afectadas. La incorporación de la tecnología a las terapias de rehabilitación ha permitido desarrollar nuevas metodologías de trabajo. Esto ha ayudado a hacer frente a las dificultades de la rehabilitación que los procesos tradicionales no logran abarcar. A pesar del gran avance realizado en los Ãoltimos años, todavía existen debilidades en el proceso de rehabilitación; por ejemplo, la trasferencia a la vida real de las habilidades logradas durante la terapia de rehabilitación, así como su generalización a otras actividades cotidianas. Los entornos virtuales pueden reproducir situaciones cotidianas. Permiten simular, de forma controlada, los requisitos conductuales que encontramos en la vida real. En un contexto terapéutico, puede ser utilizado por el neuropsicólogo para corregir en el paciente comportamientos patológicos no deseados, realizar intervenciones terapéuticas sobre Actividades de Vida Diaria que estimulen conductas adaptativas. A pesar de que las tecnologías actuales tienen potencial suficiente para aportar nuevos beneficios al proceso de rehabilitación, existe cierta reticencia a su incorporación a la clínica diaria. A día de hoy, no se ha podido demostrar que su uso aporte una mejorar significativa con respecto a otro tipo de intervención; en otras palabras, no existe evidencia científica de la eficacia del uso de entornos virtuales interactivos en rehabilitación. En este contexto, la presente Tesis Doctoral trata de abordar los aspectos que mantienen a los entornos virtuales interactivos al margen de la rutina clínica diaria. Se estudian las diferentes etapas del proceso de rehabilitación cognitiva relacionado con la integración y uso de estos entornos: diseño de las actividades, su implementación en el entorno virtual, y finalmente la ejecución por el paciente y análisis de los respectivos datos. Por tanto, los bloques en los que queda dividido el trabajo de investigación expuesto en esta memoria son: 1. Diseño de las AVD. La definición y configuración de los elementos que componen la AVD permite al terapeuta diseñar estrategias de intervención terapéutica para actuar sobre el comportamiento del paciente durante la ejecución de la actividad. En esta parte de la tesis se pretende formalizar el diseño de las AVD de tal forma que el terapeuta pueda explotar el potencial tecnológico de los entornos virtuales interactivos abstrayéndose de la complejidad implícita a la tecnología. Para hacer viable este planteamiento se propone una metodología que permita modelar la definición de las AVD, representar el conocimiento implícito en ellas, y asistir al neuropsicólogo durante el proceso de diseño de la intervención clínica. 2. Entorno virtual interactivo. El gran avance tecnológico producido durante los Ãoltimos años permite reproducir AVD interactivas en un contexto de uso clínico. El objetivo perseguido en esta parte de la Tesis es el de extraer las características potenciales de esta solución tecnológica y aplicarla a las necesidades y requisitos de la rehabilitación cognitiva. Se propone el uso de la tecnología de Vídeo Interactivo para el desarrollo de estos entornos virtuales. Para la evaluación de la misma se realiza un estudio experimental dividido en dos fases con la participación de sujetos sanos y pacientes, donde se valora su idoneidad para ser utilizado en terapias de rehabilitación cognitiva. 3. Monitorización de las AVD. El uso de estos entornos virtuales interactivos expone al paciente ante una gran cantidad de estímulos e interacciones. Este hecho requiere de instrumentos de monitorización avanzado que aporten al terapeuta información objetiva sobre el comportamiento del paciente, lo que le podría permitir por ejemplo evaluar la eficacia del tratamiento. En este apartado se propone el uso de métricas basadas en la atención visual y la interacción con el entorno para conocer datos sobre el comportamiento del paciente durante la AVD. Se desarrolla un sistema de monitorización integrado con el entorno virtual que ofrece los instrumentos necesarios para la evaluación de estas métricas para su uso clínico. La metodología propuesta ha permitido diseñar una AVD basada en la definición de intervenciones terapéuticas. Posteriormente esta AVD has sido implementada mediante la tecnología de vídeo interactivo, creando así el prototipo de un entorno virtual para ser utilizado por pacientes con déficit cognitivo. Los resultados del estudio experimental mediante el cual ha sido evaluado demuestran la robustez y usabilidad del sistema, así como su capacidad para intervenir sobre el comportamiento del paciente. El sistema monitorización que ha sido integrado con el entorno virtual aporta datos objetivos sobre el comportamiento del paciente durante la ejecución de la actividad. Los resultados obtenidos permiten contrastar las hipótesis de investigación planteadas en la Tesis Doctoral, aportando soluciones que pueden ayudar a la integración de los entornos virtuales interactivos en la rutina clínica. Esto abre una nueva vía de investigación y desarrollo que podría suponer un gran progreso y mejora en los procesos de neurorrehabilitación cognitiva en daño cerebral. ABSTRACT Brain injury (BI) refers to medical conditions that occur in the brain, altering its function. It becomes one of the main neurological disabilities in the developed society. Cognitive processes determine individual performance in Activities of Daily Living (ADL), thus, the cognitive disorders after BI result in a loss of autonomy and independence, affecting the patient’s quality of life. Cognitive rehabilitation seeks to increase patients’ autonomy and quality of life minimizing or compensating functional disorders showed by BI patients. Brain plasticity is an intrinsic property of the human nervous system whereby its structure is changed depending on experience. Neurorehabilitation pursuits a precise modulation of this intrinsic property, based on specific exercises to induce functional changes, which could result in partial or total recovery of the affected functions. The new methodologies that can be approached by applying technologies to the rehabilitation process, permit to deal with the difficulties which are out of the scope of the traditional rehabilitation. Despite this huge breakthrough, there are still weaknesses in the rehabilitation process, such as the transferring to the real life those skills reached along the therapy, and its generalization to others daily activities. Virtual environments reproduce daily situations. Behavioural requirements which are similar to those we perceive in real life, are simulated in a controlled way. In these virtual environments the therapist is allowed to interact with patients without even being present, inhibiting unsuitable behaviour patterns, stimulating correct answers throughout the simulation and enhancing stimuli with supplementary information when necessary. Despite the benefits which could be brought to the cognitive rehabilitation by applying the potential of the current technologies, there are barriers for widespread use of interactive virtual environments in clinical routine. At present, the evidence that these technologies bring a significant improvement to the cognitive therapies is limited. In other words, there is no evidence about the efficacy of using virtual environments in rehabilitation. In this context, this work aims to address those issues which keep the virtual environments out of the clinical routine. The stages of the cognitive rehabilitation process, which are related with the use and integration of these environments, are analysed: activities design, its implementation in the virtual environment, and the patient’s performance and the data analysis. Hence, the thesis is comprised of the main chapters that are listed below: 1. ADL Design.Definition and configuration of the elements which comprise the ADL allow the therapist to design intervention strategies to influence over the patient behaviour along the activity performance. This chapter aims to formalise the AVD design in order to help neuropsychologists to make use of the interactive virtual environments’ potential but isolating them from the complexity of the technology. With this purpose a new methodology is proposed as an instrument to model the ADL definition, to manage its implied knowledge and to assist the clinician along the design process of the therapeutic intervention. 2. Interactive virtual environment. Continuous advancements make the technology feasible for re-creating rehabilitation therapies based on ADL. The goal of this stage is to analyse the main features of virtual environments in order to apply them according to the cognitive rehabilitation’s requirements. The interactive video is proposed as the technology to develop virtual environments. Experimental study is carried out to assess the suitability of the interactive video to be used by cognitive rehabilitation. 3. ADL monitoring system. This kind of virtual environments bring patients in front lots of stimuli and interactions. Thus, advanced monitoring instruments are needed to provide therapist with objective information about patient’s behaviour. This thesis chapter propose the use of metrics rely on visual patients’ visual attention and their interactions with the environment. A monitoring system has been developed and integrated with the interactive video-based virtual environment, providing neuropsychologist with the instruments to evaluate the clinical force of this metrics. Therapeutic interventions-based ADL has been designed by using the proposed methodology. Interactive video technology has been used to develop the ADL, resulting in a virtual environment prototype to be use by patients who suffer a cognitive deficits. An experimental study has been performed to evaluate the virtual environment, whose overcomes show the usability and solidity of the system, and also its capacity to have influence over patient’s behaviour. The monitoring system, which has been embedded in the virtual environment, provides objective information about patients’ behaviour along their activity performance. Research hypothesis of the Thesis are proven by the obtained results. They could help to incorporate the interactive virtual environments in the clinical routine. This may be a significant step forward to enhance the cognitive neurorehabilitation processes in brain injury.

DISLEXIA E ATENÇÃO

Dislexia é uma condição neurológica associada a deficiências na aquisição e processamento da linguagem. Variando em graus de gravidade, que se manifesta por dificuldades na linguagem receptiva e expressiva, incluindo processamento fonológico, na leitura, escrita, ortografia, caligrafia, e por vezes em aritmética. Dislexia é uma condição hereditária associada a diversas anormalidades neurológicas em áreas corticais visuais e auditivas. Uma das mais influentes teorias para explicar os sintomas disléxicos é a chamada hipótese magnocelular. Segundo esta hipótese, a dislexia resulta de processamento de informações visuais anormais, devido principalmente a disfunção no sistema magnocelular. Esta dissertação explora esta hipótese comparando quinze indivíduos com dislexia e quinze controles, com idades compreendidas entre os 18 e os 30 anos através de dois testes visuais de atenção. Ambos os experimentos avaliam tempo de reação a estímulos que apareciam em toda tela do computador, enquanto os indivíduos permaneciam instalados, com a cabeça apoiada por um chin rest e com os olhos fixos em um alvo central. O experimento I consistiu de estímulos (pequenos círculos) brancos apresentados em um fundo preto. No experimento II, a mesma metodologia foi utilizada, mas agora com os estímulos (pequenos círculos) verdes sobre um fundo vermelho. Os resultados foram analisados levando em consideração os quadrantes onde os estímulos foram apresentados. Pacientes e controles não diferiram em relação ao tempo de reação a estímulos apresentados no campo visual inferior, em comparação ao quadrante superior de um mesmo indivíduo. Considerando todos os quadrantes, disléxicos tiveram tempo de reação mais lento no experimento I, mas apresentaram tempos de reação semelhantes aos controles no experimento II. Estes resultados são compatíveis com anormalidades no sistema magnocelular. As implicações destes achados para a fisiopatologia da dislexia, bem como para o seu tratamento devem ser mais discutidos.(AU)

DISLEXIA E ATENÇÃO

Dislexia é uma condição neurológica associada a deficiências na aquisição e processamento da linguagem. Variando em graus de gravidade, que se manifesta por dificuldades na linguagem receptiva e expressiva, incluindo processamento fonológico, na leitura, escrita, ortografia, caligrafia, e por vezes em aritmética. Dislexia é uma condição hereditária associada a diversas anormalidades neurológicas em áreas corticais visuais e auditivas. Uma das mais influentes teorias para explicar os sintomas disléxicos é a chamada hipótese magnocelular. Segundo esta hipótese, a dislexia resulta de processamento de informações visuais anormais, devido principalmente a disfunção no sistema magnocelular. Esta dissertação explora esta hipótese comparando quinze indivíduos com dislexia e quinze controles, com idades compreendidas entre os 18 e os 30 anos através de dois testes visuais de atenção. Ambos os experimentos avaliam tempo de reação a estímulos que apareciam em toda tela do computador, enquanto os indivíduos permaneciam instalados, com a cabeça apoiada por um chin rest e com os olhos fixos em um alvo central. O experimento I consistiu de estímulos (pequenos círculos) brancos apresentados em um fundo preto. No experimento II, a mesma metodologia foi utilizada, mas agora com os estímulos (pequenos círculos) verdes sobre um fundo vermelho. Os resultados foram analisados levando em consideração os quadrantes onde os estímulos foram apresentados. Pacientes e controles não diferiram em relação ao tempo de reação a estímulos apresentados no campo visual inferior, em comparação ao quadrante superior de um mesmo indivíduo. Considerando todos os quadrantes, disléxicos tiveram tempo de reação mais lento no experimento I, mas apresentaram tempos de reação semelhantes aos controles no experimento II. Estes resultados são compatíveis com anormalidades no sistema magnocelular. As implicações destes achados para a fisiopatologia da dislexia, bem como para o seu tratamento devem ser mais discutidos.(AU)

Neuronal coincidence detection by voltage-sensitive electrical synapses

Coincidence detection is important for functions as diverse as Hebbian learning, binaural localization, and visual attention. We show here that extremely precise coincidence detection is a natural consequence of the normal function of rectifying electrical synapses. Such synapses open to bidirectional current flow when presynaptic cells depolarize relative to their postsynaptic targets and remain open until well after completion of presynaptic spikes. When multiple input neurons fire simultaneously, the synaptic currents sum effectively and produce a large excitatory postsynaptic potential. However, when some inputs are delayed relative to the rest, their contributions are reduced because the early excitatory postsynaptic potential retards the opening of additional voltage-sensitive synapses, and the late synaptic currents are shunted by already opened junctions. These mechanisms account for the ability of the lateral giant neurons of crayfish to sum synchronous inputs, but not inputs separated by only 100 μsec. This coincidence detection enables crayfish to produce reflex escape responses only to very abrupt mechanical stimuli. In light of recent evidence that electrical synapses are common in the mammalian central nervous system, the mechanisms of coincidence detection described here may be widely used in many systems.

El lenguaje gráfico de Eduardo Chillida como aportación conceptual para la identidad tipográfica de la Universidad del País Vasco —UPV/EHU—

Este proyecto de investigación financiado por la Universidad del País Vasco/Euskal Herriko Unibertsitatea —UPV/EHU-PES 11/31—, a través de su programa de investigación estratégica, tiene como objetivo la creación de la tipografía de identidad visual corporativa de la Universidad del País Vasco —UPV/EHU—, cuyo inicio conceptual para dotar de unas características de identidad visual corporativa a la UPV/EHU, ha sido planteado desde las especulaciones estéticas sobre la forma, materializadas por Eduardo Chillida. En la producción gráfica de este artista encontramos una sutil coincidencia con principios vitales para la creación tipográfica, en cuanto al planteamiento de formas dinámicas y constructivas, en las que el rigor geométrico es vencido por una suerte de organicidad que parte del núcleo mismo de la estructura —«cursus»—, por: la fuerza vital que imprime la acción modulada del gesto —«ductus»—; por la dialéctica entre lo lleno y lo vacío —forma/contraforma—, por el impulso y la espontaneidad — carácter—, o por la afirmación de un lenguaje plástico en la cultura diferenciada del medio en el que se vive —identidad—.

Usability of a mobile, group communication prototype while rendezvousing

Mobile phones are increasingly being used collaboratively by social networks of users in spite of the fact that they are primarily designed to support single users and one-to-one communication. It is not well understood how services such as group SMS, SMS-based discussion lists and mobile instant messaging (IM) will be used by mobile groups in natural settings. Studying specific instances of common styles of in situ, group interaction may provide a way to see behavior patterns and typical interaction problems. We conducted a study of a mobile, group communication probe used during a rendezvousing activity in an urban environment. Usability problems relating to group usage, phone interface design and context were identified. Several major issues included: multitasking during message composition and reading; speed of text entry; excessive demand on visual attention; and ambiguity of intended recipients. We suggest that existing mobile device designs are overly-focused on individual users to the detriment of usability for mobile groups of users. We provide recommendations for the design of future mobile, group interfaces, used in similar situations to those explored here

DISLEXIA E ATENÇÃO

Dislexia é uma condição neurológica associada a deficiências na aquisição e processamento da linguagem. Variando em graus de gravidade, que se manifesta por dificuldades na linguagem receptiva e expressiva, incluindo processamento fonológico, na leitura, escrita, ortografia, caligrafia, e por vezes em aritmética. Dislexia é uma condição hereditária associada a diversas anormalidades neurológicas em áreas corticais visuais e auditivas. Uma das mais influentes teorias para explicar os sintomas disléxicos é a chamada hipótese magnocelular. Segundo esta hipótese, a dislexia resulta de processamento de informações visuais anormais, devido principalmente a disfunção no sistema magnocelular. Esta dissertação explora esta hipótese comparando quinze indivíduos com dislexia e quinze controles, com idades compreendidas entre os 18 e os 30 anos através de dois testes visuais de atenção. Ambos os experimentos avaliam tempo de reação a estímulos que apareciam em toda tela do computador, enquanto os indivíduos permaneciam instalados, com a cabeça apoiada por um chin rest e com os olhos fixos em um alvo central. O experimento I consistiu de estímulos (pequenos círculos) brancos apresentados em um fundo preto. No experimento II, a mesma metodologia foi utilizada, mas agora com os estímulos (pequenos círculos) verdes sobre um fundo vermelho. Os resultados foram analisados levando em consideração os quadrantes onde os estímulos foram apresentados. Pacientes e controles não diferiram em relação ao tempo de reação a estímulos apresentados no campo visual inferior, em comparação ao quadrante superior de um mesmo indivíduo. Considerando todos os quadrantes, disléxicos tiveram tempo de reação mais lento no experimento I, mas apresentaram tempos de reação semelhantes aos controles no experimento II. Estes resultados são compatíveis com anormalidades no sistema magnocelular. As implicações destes achados para a fisiopatologia da dislexia, bem como para o seu tratamento devem ser mais discutidos.(AU)

The role of oscillatory brain activity in object processing and figure-ground segmentation in human vision

The perception of an object as a single entity within a visual scene requires that its features are bound together and segregated from the background and/or other objects. Here, we used magnetoencephalography (MEG) to assess the hypothesis that coherent percepts may arise from the synchronized high frequency (gamma) activity between neurons that code features of the same object. We also assessed the role of low frequency (alpha, beta) activity in object processing. The target stimulus (i.e. object) was a small patch of a concentric grating of 3c/°, viewed eccentrically. The background stimulus was either a blank field or a concentric grating of 3c/° periodicity, viewed centrally. With patterned backgrounds, the target stimulus emerged--through rotation about its own centre--as a circular subsection of the background. Data were acquired using a 275-channel whole-head MEG system and analyzed using Synthetic Aperture Magnetometry (SAM), which allows one to generate images of task-related cortical oscillatory power changes within specific frequency bands. Significant oscillatory activity across a broad range of frequencies was evident at the V1/V2 border, and subsequent analyses were based on a virtual electrode at this location. When the target was presented in isolation, we observed that: (i) contralateral stimulation yielded a sustained power increase in gamma activity; and (ii) both contra- and ipsilateral stimulation yielded near identical transient power changes in alpha (and beta) activity. When the target was presented against a patterned background, we observed that: (i) contralateral stimulation yielded an increase in high-gamma (>55 Hz) power together with a decrease in low-gamma (40-55 Hz) power; and (ii) both contra- and ipsilateral stimulation yielded a transient decrease in alpha (and beta) activity, though the reduction tended to be greatest for contralateral stimulation. The opposing power changes across different regions of the gamma spectrum with 'figure/ground' stimulation suggest a possible dual role for gamma rhythms in visual object coding, and provide general support of the binding-by-synchronization hypothesis. As the power changes in alpha and beta activity were largely independent of the spatial location of the target, however, we conclude that their role in object processing may relate principally to changes in visual attention.

The observant mind:self-awareness of attentional status

Visual perception is dependent not only on low-level sensory input but also on high-level cognitive factors such as attention. In this paper, we sought to determine whether attentional processes can be internally monitored for the purpose of enhancing behavioural performance. To do so, we developed a novel paradigm involving an orientation discrimination task in which observers had the freedom to delay target presentation--by any amount required--until they judged their attentional focus to be complete. Our results show that discrimination performance is significantly improved when individuals self-monitor their level of visual attention and respond only when they perceive it to be maximal. Although target delay times varied widely from trial-to-trial (range 860 ms-12.84 s), we show that their distribution is Gaussian when plotted on a reciprocal latency scale. We further show that the neural basis of the delay times for judging attentional status is well explained by a linear rise-to-threshold model. We conclude that attentional mechanisms can be self-monitored for the purpose of enhancing human decision-making processes, and that the neural basis of such processes can be understood in terms of a simple, yet broadly applicable, linear rise-to-threshold model.

Transcranial magnetic stimulation to right parietal cortex modifies the attentional blink

The 'attentional blink' (AB) reflects a limitation in the ability to identify multiple items in a stream of rapidly presented information. Repetitive transcranial magnetic stimulation (rTMS), applied to a site over the right posterior parietal cortex, reduced the magnitude of the AB to visual stimuli, whilst no effect of rTMS was found when stimulation took place at a control site. The data confirm that the posterior parietal cortex may play a critical role in temporal as well as spatial aspects of visual attention.

Shining in the center:central gaze cascade effect on product choice

Consumers' tendency to choose the option in the center of an array and the process underlying this effect is explored. Findings from two eye-tracking studies suggest that brands in the horizontal center receive more visual attention. They are more likely to be chosen. Investigation of the attention process revealed an initial central fixation bias, a tendency to look first at the central option, and a central gaze cascade effect, progressively increasing attention focused on the central option right prior to decision. Only the central gaze cascade effect was related to choice. An offline study with tangible products demonstrated that the centrally located item within a product category is chosen more often, even when it is not placed in the center of the visual field. Despite widespread use, memory-based attention measures were not correlated with eye-tracking measures. They did not capture visual attention and were not related to choice. © 2012 by JOURNAL OF CONSUMER RESEARCH, Inc.

The spatial distribution and temporal dynamics of brain regions activated during the perception of object and non-object patterns

Both animal and human studies suggest that the efficiency with which we are able to grasp objects is attributable to a repertoire of motor signals derived directly from vision. This is in general agreement with the long-held belief that the automatic generation of motor signals by the perception of objects is based on the actions they afford. In this study, we used magnetoencephalography (MEG) to determine the spatial distribution and temporal dynamics of brain regions activated during passive viewing of object and non-object targets that varied in the extent to which they afforded a grasping action. Synthetic Aperture Magnetometry (SAM) was used to localize task-related oscillatory power changes within specific frequency bands, and the time course of activity within given regions-of-interest was determined by calculating time-frequency plots using a Morlet wavelet transform. Both single subject and group-averaged data on the spatial distribution of brain activity are presented. We show that: (i) significant reductions in 10-25 Hz activity within extrastriate cortex, occipito-temporal cortex, sensori-motor cortex and cerebellum were evident with passive viewing of both objects and non-objects; and (ii) reductions in oscillatory activity within the posterior part of the superior parietal cortex (area Ba7) were only evident with the perception of objects. Assuming that focal reductions in low-frequency oscillations (< 30 Hz) reflect areas of heightened neural activity, we conclude that: (i) activity within a network of brain areas, including the sensori-motor cortex, is not critically dependent on stimulus type and may reflect general changes in visual attention; and (ii) the posterior part of the superior parietal cortex, area Ba7, is activated preferentially by objects and may play a role in computations related to grasping. © 2006 Elsevier Inc. All rights reserved.

Consumer responses to really new products: examining the impacts of learning strategies and presentation formats on product comprehension and attitude formation

Mental simulations and analogies have been identified as powerful learning tools for RNPs. Furthermore, visuals in advertising have recently been conceptualized as meaningful sources of information as opposed to peripheral cues and thus may help consumers learn about RNPs. The study of visual attention may also contribute to understanding the links between conceptual and perceptual analyses when learning for a RNP. Two conceptual models are developed. the first model consists of causal relationships between the attributes of advertising stimuli for RNPs and consumer responses, as well as mediating influences. The second model focuses on the role of visual attention in product comprehension as a response to advertising stimuli. Two experiments are conducted: a Web-Experiment and an eye-tracking experiment. The first experiment (858 subjects) examines the effect of learning strategies (mental simulation vs. analogy vs. no analogy/no mental simulation) and presentation formats (words vs. pictures) on individual responses. The mediating role of emotions is assessed. The second experiment investigates the effect of learning strategies and presentation formats on product comprehension, along with the role of attention (17 subjects). The findings from experiment 1 indicate that learning strategies and presentation formats can either enhance or undermine the effect of advertising stimuli on individual responses. Moreover, the nature of the product (i.e. hedonic vs. utilitarian vs. hybrid) should be considered when designing communications for RNPs. The mediating role of emotions is verified. Experiment 2 suggests that an increase in attention to the message may either reflect enhanced comprehension or confusion.

Effect of fatigue on consumers' advertising processing

Huge advertising budgets are invested by firms to reach and convince potential consumers to buy their products. To optimize these investments, it is fundamental not only to ensure that appropriate consumers will be reached, but also that they will be in appropriate reception conditions. Marketing research has focused on the way consumers react to advertising, as well as on some individual and contextual factors that could mediate or moderate the ad impact on consumers (e.g. motivation and ability to process information or attitudes toward advertising). Nevertheless, a factor that potentially influences consumers’ advertising reactions has not yet been studied in marketing research: fatigue. Fatigue can yet impact key variables of advertising processing, such as cognitive resources availability (Lieury 2004). Fatigue is felt when the body warns to stop an activity (or inactivity) to have some rest, allowing the individual to compensate for fatigue effects. Dittner et al. (2004) defines it as “the state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli.’’ It signals that resources will lack if we continue with the ongoing activity. According to Schmidtke (1969), fatigue leads to troubles in information reception, in perception, in coordination, in attention getting, in concentration and in thinking. In addition, for Markle (1984) fatigue generates a decrease in memory, and in communication ability, whereas it increases time reaction, and number of errors. Thus, fatigue may have large effects on advertising processing. We suggest that fatigue determines the level of available resources. Some research about consumer responses to advertising claim that complexity is a fundamental element to take into consideration. Complexity determines the cognitive efforts the consumer must provide to understand the message (Putrevu et al. 2004). Thus, we suggest that complexity determines the level of required resources. To study this complex question about need and provision of cognitive resources, we draw upon Resource Matching Theory. Anand and Sternthal (1989, 1990) are the first to state the Resource Matching principle, saying that an ad is most persuasive when the resources required to process it match the resources the viewer is willing and able to provide. They show that when the required resources exceed those available, the message is not entirely processed by the consumer. And when there are too many available resources comparing to those required, the viewer elaborates critical or unrelated thoughts. According to the Resource Matching theory, the level of resource demanded by an ad can be high or low, and is mostly determined by the ad’s layout (Peracchio and Myers-Levy, 1997). We manipulate the level of required resources using three levels of ad complexity (low – high – extremely high). On the other side, the resource availability of an ad viewer is determined by lots of contextual and individual variables. We manipulate the level of available resources using two levels of fatigue (low – high). Tired viewers want to limit the processing effort to minimal resource requirements by making heuristics, forming overall impression at first glance. It will be easier for them to decode the message when ads are very simple. On the contrary, the most effective ads for viewers who are not tired are complex enough to draw their attention and fully use their resources. They will use more analytical strategies, looking at the details of the ad. However, if ads are too complex, they will be too difficult to understand. The viewer will be discouraged to process information and will overlook the ad. The objective of our research is to study fatigue as a moderating variable of advertising information processing. We run two experimental studies to assess the effect of fatigue on visual strategies, comprehension, persuasion and memorization. In study 1, thirty-five undergraduate students enrolled in a marketing research course participated in the experiment. The experimental design is 2 (tiredness level: between subjects) x 3 (ad complexity level: within subjects). Participants were randomly assigned a schedule time (morning: 8-10 am or evening: 10-12 pm) to perform the experiment. We chose to test subjects at various moments of the day to obtain maximum variance in their fatigue level. We use Morningness / Eveningness tendency of participants (Horne & Ostberg, 1976) as a control variable. We assess fatigue level using subjective measures - questionnaire with fatigue scales - and objective measures - reaction time and number of errors. Regarding complexity levels, we have designed our own ads in order to keep aspects other than complexity equal. We ran a pretest using the Resource Demands scale (Keller and Bloch 1997) and by rating them on complexity like Morrison and Dainoff (1972) to check for our complexity manipulation. We found three significantly different levels. After having completed the fatigue scales, participants are asked to view the ads on a screen, while their eye movements are recorded by the eye-tracker. Eye-tracking allows us to find out patterns of visual attention (Pieters and Warlop 1999). We are then able to infer specific respondents’ visual strategies according to their level of fatigue. Comprehension is assessed with a comprehension test. We collect measures of attitude change for persuasion and measures of recall and recognition at various points of time for memorization. Once the effect of fatigue will be determined across the student population, it is interesting to account for individual differences in fatigue severity and perception. Therefore, we run study 2, which is similar to the previous one except for the design: time of day is now within-subjects and complexity becomes between-subjects

Separating the influences of prereading skills on early word and nonword reading

The essential first step for a beginning reader is to learn to match printed forms to phonological representations. For a new word, this is an effortful process where each grapheme must be translated individually (serial decoding). The role of phonological awareness in developing a decoding strategy is well known. We examined whether beginner readers recruit different skills depending on the nature of the words being read (familiar words vs. nonwords). Print knowledge, phoneme and rhyme awareness, rapid automatized naming (RAN), phonological short term memory (STM), nonverbal reasoning, vocabulary, auditory skills and visual attention were measured in 392 pre-readers aged 4 to 5 years. Word and nonword reading were measured 9 months later. We used structural equation modeling to examine the skills-reading relationship and modeled correlations between our two reading outcomes and among all pre-reading skills. We found that a broad range of skills were associated with reading outcomes: early print knowledge, phonological STM, phoneme awareness and RAN. Whereas all these skills were directly predictive of nonword reading, early print knowledge was the only direct predictor of word reading. Our findings suggest that beginner readers draw most heavily on their existing print knowledge to read familiar words.