Elevated gamma-globulin and increased antibody production in mice infected with lactic dehydrogenase virus.

Infection of mice with the lactic dehydrogenase virus (LDV) resulted in an elevated level of gamma-globulin. Histologic examination of the spleen and lymph nodes revealed that the number of germinal centers was greatly increased. Immunization with human gamma-globulin showed that the capacity of the virus-infected animal to produce anti-human gamma-globulin was greatly enhanced and that the virus acted as an adjuvant. From these experiments it is concluded that a virus infection (LDV) can affect the immunologic response of the host to a heterologous antigen.

The Influence of Methylphenidate on Hyperactivity and Attention Deficits in Children With ADHD: A Virtual Classroom Test.

Objective: This study compares the performance in a continuous performance test within a virtual reality classroom (CPT-VRC) between medicated children with ADHD, unmedicated children with ADHD, and healthy children. Method:N = 94 children with ADHD (n = 26 of them received methylphenidate and n = 68 were unmedicated) and n = 34 healthy children performed the CPT-VRC. Omission errors, reaction time/variability, commission errors, and body movements were assessed. Furthermore, ADHD questionnaires were administered and compared with the CPT-VRC measures. Results: The unmedicated ADHD group exhibited more omission errors and showed slower reaction times than the healthy group. Reaction time variability was higher in the unmedicated ADHD group compared with both the healthy and the medicated ADHD group. Omission errors and reaction time variability were associated with inattentiveness ratings of experimenters. Head movements were correlated with hyperactivity ratings of parents and experimenters. Conclusion: Virtual reality is a promising technology to assess ADHD symptoms in an ecologically valid environment.

Gender comparisons of cognitive performances among vascular dementia, Alzheimer disease, and older adults without dementia.

BACKGROUND: We hypothesized that women with Alzheimer disease (AD) would perform worse on a test of semantic memory but not on tests of other cognitive domains. We did not expect that women without dementia would perform more poorly than men without dementia on the same task. OBJECTIVE: To explore the specificity of a semantic memory deficit among women with AD by exploring gender differences among a group of subjects with vascular dementia (VD). DESIGN: A case-control study in which differences between men and women were explored using regression models to control for the potentially confounding effects of age, education, duration of dementia, and severity of dementia. SETTING: Alzheimer's Disease Research Center Consortium of Los Angeles and Orange Counties, California. SUBJECTS: Volunteers, recruited from the community or clinic referrals, who met clinical criteria for AD (n = 159) or VD (n = 117) or met criteria for control status without dementia (n = 134). MAIN OUTCOME MEASURES: Five neuropsychological measures, commonly used in the diagnosis and assessment of dementia. RESULTS: Women with VD scored lower than men with VD on 3 tests. However, when controlling for potential confounds, the gender difference was maintained only for the semantic memory task. Women with AD showed a strong trend to perform worse than men with AD on the test of semantic memory only. No gender differences were found among subjects without dementia. CONCLUSIONS: Findings support the existence of a semantic memory deficit for women with AD and suggest that a similar deficit may exist among women with VD.

Associations between circulating sex steroid hormones and cognition in normal elderly women.

OBJECTIVE: To provide exploratory analyses of associations between levels of several sex hormones and cognitive performance in elderly women. BACKGROUND: Sex steroid hormones are implicated in the cognitive processes of the adult brain. Comparing cognitive performance across or between conditions associated with different hormone levels, such as phases of the menstrual cycle, surgical menopause, and estrogen replacement therapy suggests conditions with higher levels of estrogen are associated with better verbal memory and possibly worse visuospatial ability. METHOD: The authors measured circulating sex hormone levels in 39 highly educated, nondemented, predominantly white elderly women. Levels were correlated with neuropsychological performance, controlling for age, education, frequency of prior testing, use of estrogen replacement, and depression. RESULTS: High estradiol levels were associated with better delayed verbal memory and retrieval efficiency, whereas low levels were associated with better immediate and delayed visual memory. Levels of testosterone were related positively to verbal fluency. Levels of progesterone and androstenedione were unrelated to cognitive performance. CONCLUSIONS: Both estrogen and testosterone showed associations with cognitive performance. Estrogen may enhance, and depress, specific cognitive skills.

Effects of caffeine withdrawal on motor performance and heart rate changes.

Heavy caffeine Users and Non-users were tested twice using a signalled reaction time paradigm, while heart rate was recorded. During the 7-day interval between the two sessions, the User group maintained normal caffeine intake for the first 5 days and abstained from caffeine during the last 2 days, which constituted a withdrawal period. The Non-users abstained from caffeine (as they usually do) during the entire 7-day period. The analyses of the reaction time (RT) data indicated no differences during Session 1 and a significant group difference during Session 2, with the Non-users exhibiting faster RT's. The Users exhibited no change between Sessions 1 and 2, while the Non-users showed a decrease in RT's (increased speed) across Sessions, which may be indicative of a practice effect. The analysis of the heart rate data from the 5-s period prior to the imperative stimulus yielded no differences during Session 1, and a significant group difference in Session 2, with the Non-users exhibiting larger decelerations. Across the two Sessions, the Non-users showed an increase in the magnitude of the heart rate deceleration, while the Users exhibited a decline in the size of the deceleration. Since the magnitude of heart rate deceleration has been interpreted as an index of attention, it appears that the Users were exhibiting less efficient attention during withdrawal from caffeine (Session 2) than were the Non-users. This conclusion is supported by the RT data, showing slower response times for the Users during Session 2, as compared to Non-users.

Long-term follow-up (3-4 years) of treatment for smoking reduction.

The present paper reports the 3- and 4-year follow-ups of two smoking reduction clinics (n = 103) employing a comprehensive, non-aversive, behavioral treatment using stimulus control and self-control techniques. Most of the data were gathered via phone contact, while some clients were interviewed in person with corroborative carbon monoxide measurements taken at that time. While the general findings were similar to those reported for other long-term follow-ups of smoking programs, unlike earlier reports, the overwhelming majority of subjects were contacted (an average of 90% for all follow-up periods). The average percentage of baseline for smoking subjects was equal to 56% and average percentage abstinent equal to 24% at final follow-up. Data are also presented which suggest greater attention be paid to the potential efficacy of controlled smoking when assessing the effectiveness of smoking reduction programs.

The saliva thiocyanate analysis: a methodological extension and its relationship to CO and self-report in moderate smokers.

Parameters for the storage and analysis of saliva samples used to measure thiocyanate (SCN) levels among moderate smokers were systematically studied. The variables targeted for study were the temperature of storage (0 to 20 degrees F) and the size of the container (5 ml or 10 ml). Additionally, these same variables were examined, independently under three different temporal delays to laboratory analysis: immediate, 3 days, and 7 days. Results within each of the delay conditions revealed no significant differences in SCN levels and provided support for the reliability of measurement when using these procedures in the study of thiocyanate levels. Self-reported smoking rate and alveolar carbon monoxide (COa) readings of a week prior were found to correlate relatively highly with thiocyanate readings. These findings broaden the support for SCN as a corroborative measure of smoking.

Performance-driven facial animation: basic research on human judgments of emotional state in facial avatars.

Virtual reality is rapidly evolving into a pragmatically usable technology for mental health (MH) applications. As the underlying enabling technologies continue to evolve and allow us to design more useful and usable structural virtual environments (VEs), the next important challenge will involve populating these environments with virtual representations of humans (avatars). This will be vital to create mental health VEs that leverage the use of avatars for applications that require human-human interaction and communication. As Alessi et al.1 pointed out at the 8th Annual Medicine Meets Virtual Reality Conference (MMVR8), virtual humans have mainly appeared in MH applications to "serve the role of props, rather than humans." More believable avatars inhabiting VEs would open up possibilities for MH applications that address social interaction, communication, instruction, assessment, and rehabilitation issues. They could also serve to enhance realism that might in turn promote the experience of presence in VR. Additionally, it will soon be possible to use computer-generated avatars that serve to provide believable dynamic facial and bodily representations of individuals communicating from a distance in real time. This could support the delivery, in shared virtual environments, of more natural human interaction styles, similar to what is used in real life between people. These techniques could enhance communication and interaction by leveraging our natural sensing and perceiving capabilities and offer the potential to model human-computer-human interaction after human-human interaction. To enhance the authenticity of virtual human representations, advances in the rendering of facial and gestural behaviors that support implicit communication will be needed. In this regard, the current paper presents data from a study that compared human raters' judgments of emotional expression between actual video clips of facial expressions and identical expressions rendered on a three-dimensional avatar using a performance-driven facial animation (PDFA) system developed at the University of Southern California Integrated Media Systems Center. PDFA offers a means for creating high-fidelity visual representations of human faces and bodies. This effort explores the feasibility of sensing and reproducing a range of facial expressions with a PDFA system. In order to test concordance of human ratings of emotional expression between video and avatar facial delivery, we first had facial model subjects observe stimuli that were designed to elicit naturalistic facial expressions. The emotional stimulus induction involved presenting text-based, still image, and video clips to subjects that were previously rated to induce facial expressions for the six universals2 of facial expression (happy, sad, fear, anger, disgust, and surprise), in addition to attentiveness, puzzlement and frustration. Videotapes of these induced facial expressions that best represented prototypic examples of the above emotional states and three-dimensional avatar animations of the same facial expressions were randomly presented to 38 human raters. The raters used open-end, forced choice and seven-point Likert-type scales to rate expression in terms of identification. The forced choice and seven-point ratings provided the most usable data to determine video/animation concordance and these data are presented. To support a clear understanding of this data, a website has been set up that will allow readers to view the video and facial animation clips to illustrate the assets and limitations of these types of facial expression-rendering methods (www. USCAvatars.com/MMVR). This methodological first step in our research program has served to provide valuable human user-centered feedback to support the iterative design and development of facial avatar characteristics for expression of emotional communication.

Virtual environments for targeting cognitive processes: an overview of projects at the University of Southern California.

The Virtual Environments Laboratory at the University of Southern California (USC) has initiated a research program aimed at developing virtual reality (VR) technology applications for the study, assessment, and rehabilitation of cognitive processes. This technology is seen to offer many advantages for these aims. The status of two ongoing VR projects will be discussed in this article. The projects outlined are being conducted via cooperative efforts with both the Integrated Media Systems Center and the Information Sciences Institute at USC. These departments consist of a multidisciplinary group of scientists that represents engineering, computer science, communications, information technology, education, and psychology. This mix of expertise has served to facilitate the development of these projects via an integrated approach to VR application development. The first project involves the development of a series of ImmersaDesk-delivered visuospatial tests and training tools that leverage the interactive, dynamic, and 3D assets that are available with current VR technology. The second project involves a head mounted display (HMD) VR system for the study, assessment, and possible rehabilitation of attention disorders. It is believed that these projects target cognitive variables that are well matched to the current strengths and limitations that exist with presently available VR technology.

Gender issues in the use of virtual environments.

Gender differences in cognitive and behavioral performance have been reported throughout the psychological literature. Consequently, gender differences should be considered and controlled for when cognitive research is conducted in virtual environments (VEs). These variables may include gender-related differences in cognitive performance, susceptibility for cybersickness, and the impact of sex hormones on cognition. Such issues are addressed in the context of a recent VE study of the visuospatial ability referred to as mental rotation. The Mental Rotation Test (MRT), a paper and pencil measure, has been shown to produce one of the largest gender differences in the cognitive literature. The outcomes of the MRT are in favor of males. However, results reported from a Virtual Reality Spatial Rotation (VRSR) test demonstrate no gender differences when subjects were able to manually manipulate the stimuli in a VE. Further analysis uncovers gender differences in the patterns of associations between verbal and spatial tasks and performance on VRSR. Results are discussed in terms of dimensionality factors and hemispheric lateralization.

Virtual reality and cognitive assessment and rehabilitation: the state of the art.

VR offers the potential to develop human testing and training environments that allow for the precise control of complex stimulus presentations in which human cognitive and functional performance can be accurately assessed and rehabilitated. However, basic feasibility issues need to be addressed in order for this technology to be reasonably and efficiently applied to the neuropsychological assessment (NA) and cognitive rehabilitation (CR) of persons with acquired brain injury and neurological disorders. This chapter will provide an introduction to the basic concepts of neuropsychological assessment and cognitive rehabilitation along with rationales for virtual reality's applicability in these complimentary fields. We review the relevant literature regarding theoretical and pragmatic issues for these applications, and provide a description of our ongoing work developing a mental rotation/spatial skills cognitive assessment and training system. References are provided in each section for further reading in each area reviewed.

Basic issues in the use of virtual environments for mental health applications.

In order for Virtual Environments (VE) to be efficiently developed in the areas of clinical psychology and neuropsychology, a number of basic theoretical and pragmatic issues need to be considered. The current status of VE's in these fields, while provocative, is limited by the small number of controlled studies that have been reported which apply this technology to clinical populations. This is to be expected considering it's relatively recent development, expense, and the lack of familiarity with the technology by mainstream researchers in these fields. In spite of this, some work has emerged which can begin to provide a basic foundation of knowledge which could be useful for guiding future research efforts. Although much of the work does not involve the use of fully immersive head mounted displays (HMD's), studies reporting PC-based flatscreen approaches are providing valuable information on issues necessary for the reasonable and measured development of VE/mental health applications. In light of this, the following review will focus on basic issues that we see as important for the development of both HMD and non-HMD VE applications for clinical psychology, neuropsychological assessment, and cognitive rehabilitation. These basic issues are discussed in terms of decision-making for choosing to develop and apply a VE for a mental health application. The chapter covers the issues involved with choosing a VE approach over already existing methods, deciding on the "fit" between a VE approach and the clinical population, level of presence, navigation factors, side effects, generalization, and general methodological and data analysis concerns.

The potential of virtual reality and gaming to assist successful aging with disability.

Using the advances in computing power, software and hardware technologies, virtual reality (VR), and gaming applications have the potential to address clinical challenges for a range of disabilities. VR-based games can potentially provide the ability to assess and augment cognitive and motor rehabilitation under a range of stimulus conditions that are not easily controllable and quantifiable in the real world. This article discusses an approach for maximizing function and participation for those aging with and into a disability by combining task-specific training with advances in VR and gaming technologies to enable positive behavioral modifications for independence in the home and community. There is potential for the use of VR and game applications for rehabilitating, maintaining, and enhancing those processes that are affected by aging with and into disability, particularly the need to attain a balance in the interplay between sensorimotor function and cognitive demands and to reap the benefits of task-specific training and regular physical activity and exercise.