Neurophysiological age differences during task-performance in a stereoscopic virtual environment

In today's society, there is an increasing number of workplaces in virtual environments (VE). But, there are only a few reports dealing with occupational health issues or age effects. The question arises how VR generally interferes with cognitive processes. This interference might have relevant implications for workability and work-efficiency in virtual environments. Event-related potentials are known to reflect different stages of stimulus reception, evaluation, and response. We have established an electroencephalographic (EEG) monitoring, focussing on event-related potentials (N100; mismatch negativity, i.e., MMN) to obtain access to attention dependent and pre-attentive processing of sensory stimuli applied in VE. The MMN is known to be correlated with the ability of subjects to react to an unexpected event. The aim of the present study was to investigate cognitive responses to distracting auditory stimuli in two different age groups in a virtual environment (VE) and in a real environment ("real reality"), and to compare characteristic neurophysiological response patterns. Data show that stimulus detection as given by the N100 amplitude and latency does not differ in both age groups and task conditions. In contrast, the pre-attentive processing as given by the MMN is altered in the VR such as the non-VR condition in an age-related manner. A relevant finding of the present study was that the age related differences seen in the non-VR condition were not strengthened in VR.

Cognitive ergonomics in virtual environments: development of an intuitive and appropriate input device for navigating in a virtual maze

For patients suffering from mild cognitive impairments, the navigation through a virtual maze should be as intuitive and efficient as possible in order to minimize cognitive and physical strain. This paper discusses the appropriateness of interaction devices for being used for easy navigation tasks. Information gained from human centered evaluation was used to develop an intuitive and ergonomic interaction device. Two experiments examined the usability of tracked interaction devices. Usability problems with the devices are discussed. The findings from the experiments were translated into general design guidance, in addition to specific recommendations. A new device was designed on the basis of these recommendations and its usability was evaluated in a second experiment. The results were used to develop a lightweight interaction device for navigation in the virtual maze.

Stimulation of Cortisol During Mental Task Performance in a Provocative Virtual Environment

Fully immersive and stereoscopic Virtual Environments (VE) represent a powerful multimedia tool for laboratory-based simulations of distinct scenarios including scenarios for evaluating stressful situations resembling reality. Thus far, cortisol secretion as a neuroendocrine parameter of stress has not been evaluated within a Virtual Reality (VR)-based paradigm. In this study 94 healthy volunteers were subjected to a provocative VR-paradigm and a cognitive stress task. Provocative in this context means the VE was designed to provoke physiological reactions (cortisol secretion) within the respective users by purpose. It was tested (a) if a fully dynamic VE as opposed to a static VE can be regarded as a stressor and (b) if such a fully dynamic VE can modify an additional response to a cognitive stressor presented within the VE additionally. Furthermore, possible gender-related impacts on cortisol responses were assessed. A significant cortisol increase was observed only after the combined application of the fully dynamic VE and the cognitive stressor, but not after application of the dynamic VE or the cognitive stressor alone. Cortisol reactivity was greater for men than for women. We conclude that a fully dynamic VE does not affect cortisol secretion per se, but increases cortisol responses to a dual task paradigm that includes performance of a stressful mental task. This provides the basis for the application of VR-based technologies in neuroscientific research, including the assessment of the human Hypothalamus-Pituitary-Adrenal (HPA) axis regulation.

Modification of virtual reality combined with a mental task stimulates cortisol in volunteers

Immersive, stereoscopic virtual reality (VR) systems provide a powerful multimedia tool for a laboratory simulation of distinct scenarios including stressful situations close to reality. Thus far, cortisol secretion as a neuroendocrine parameter of stress has not been evaluated within a VR paradigm. Ninety-four healthy subjects were subjected to a VR paradigm and a cognitive stress task. It was tested (a) if the modification of reality induced by dynamic VR as opposed to static VR can be regarded as a stressor and (b) if it can modify an additional cognitive stress response. In addition, the impact of gender on cortisol responses was assessed. A significant cortisol increase was observed only after the combined application of both conditions, but not after the dynamic VR or the cognitive stress alone. Cortisol reactivity was greater for men than for women. We conclude that dynamic VR does not affect cortisol secretion per se, but increases cortisol responses in a dual task paradigm. This provides the basis for the application of VR in neuroscientific research, which includes the assessment of hypothalamus-pituitary-adrenal axis regulation.

Safety of injectable opioid maintenance treatment for heroin dependence

BACKGROUND

There is a growing debate about injectable opioid treatment programs in many Western countries. This is the first placebo-controlled study of the safety of injectable opioids in a controlled treatment setting.

METHODS

Twenty-five opioid-dependent patients on intravenous (IV) heroin or IV methadone maintenance treatment were randomly assigned to either their individual prescribed IV maintenance dose or placebo. Acute drug effects were recorded, focusing on electrocardiography, respiratory movements, arterial blood oxygen saturation, and electroencephalography (EEG).

RESULTS

After heroin injection, marked respiratory depression progressing to a Cheyne-Stokes pattern occurred. Peripheral arterial blood oxygenation decreased to 78.9 +/- 8.7% (mean +/- SD) ranging from 52%-90%. During hypoxia, 7 of the 16 subjects experienced intermittent and somewhat severe bradycardia. Five subjects exhibited paroxysmal EEG patterns. After methadone injection, respiratory depression was less pronounced than after heroin injection. No relevant bradycardia was noted.

CONCLUSIONS

Opioid doses commonly prescribed in IV opioid treatment induce marked respiratory and circulatory depression, as well as occasionally irregular paroxysmal EEG activity. Further studies are needed to optimize the clinical practice of IV opioid treatment to prevent serious complications. Moreover, the extent of the observed effects raises questions about the appropriateness of IV opioid treatment in the present form.

Ethical codes and values in a virtual world

Some members of the so-called virtual world deny that technology such as the virtual environment (VE) is value-laden. But there are a variety of complex issues which arise in VE that make it necessary to think about ethics and values in VE applications. Using VE in therapy and psychotherapy research or diagnostics leads to several ethical concerns. VE can impoverish those aspects of life that are essential to social development, interpersonal relations, and emotional growth. This paper will focus on the concept called "virtual world," a question of metaphysics. After reviewing general ethical principles, ethics in applied sciences will be described. Ethical decision-making, code of conduct, and specific issues in VE will be discussed. The VE community is challenged to set guidelines around VE, and its ethics and values. A set of measurement tools around ethical codes and values in a virtual world ought to be discursively gained in this virtual world and in real society as a whole.

Real-time monitoring of brain activity in patients with specific phobia during exposure therapy, employing a stereoscopic virtual environment

Exposure therapy is a behavioral technique that is reported to be the most effective, long-lasting treatment for patients suffering from specific phobia. During the performance in enclosed spaces, the patients show a strong psychophysiological response to the phobic stimulus that is normally avoided. This psychophysiological response changes characteristically during the course of exposure. We implemented an electroencephalographic monitoring focusing on event-related potentials to resolve the modulation of preattentive information processing by the anxiety state of the subject. Therefore, mismatch-negativity (MMN) was chosen as parameter using a passive auditory oddball paradigm that does not interfere with performance in the virtual environment. The results of this neurophysiological monitoring are demonstrated in one patient suffering from claustrophobia.

Immersive virtual environments in cue exposure

Cue reactivity to drug-related stimuli is a frequently observed phenomenon in drug addiction. Cue reactivity refers to a classical conditioned response pattern that occurs when an addicted subject is exposed to drug-related stimuli. This response consists of physiological and cognitive reactions. Craving, a subjective desire to use the drug of choice, is believed to play an important role in the occurrence of relapse in the natural setting. Besides craving, other subjective cue-elicited reactions have been reported, including withdrawal symptoms, drug-agonistic effects, and mood swings. Physiological reactions that have been investigated include skin conductance, heart rate, salivation, and body temperature. Conditioned reactivity to cues is an important factor in addiction to alcohol, nicotine, opiates, and cocaine. Cue exposure treatment (CET) refers to a manualized, repeated exposure to drug-related cues, aimed at the reduction of cue reactivity by extinction. In CET, different stimuli are presented, for example, slides, video tapes, pictures, or paraphernalia in nonrealistic, experimental settings. Most often assessments consist in subjective ratings by craving scales. Our pilot study will show that immersive virtual reality (IVR) is as good or even better in eliciting subjective and physiological craving symptoms as classical devices.

From toy to tool: the development of immersive virtual reality environments for psychotherapy of specific phobias

Virtual Reality (VR) entered the mental health field some years ago. While the technology itself has been available for more than ten years now, there is still a certain amount of uncertainty among researchers and users as to whether VR will one day fulfill all it's promises. In this chapter we are giving an overview of the implementation of the technology in our mental health research facility in Basel, Switzerland. The development of two applications for use with claustrophobic and acrophobic patients perspectively serves just as an example within this context. Some may say, the chapter is too much based on technical considerations. Strictly speaking, VR is pure technology, even knowing that this special form of technology has sensory, psychological and even philosophical implications not known from other human computer interfaces so far. As far as we are concerned, the development of the technology for use within the mental health sector has merely just begun. As today's mostly used immersive output devices (Head-mounted Displays, shutter glasses) do not have a satisfactory resolution, do restrict movements and prevent multi-user-capabilities, there will be a soar of mental health applications the day some or at least the most important of these obstacles have been overcome.

Pathological cerebral blood flow during motor function in schizophrenic and endogenous depressed patients

In this investigation we examined eight Type I (positive symptoms without marked negative symptomatology), eight Type II (marked negative symptoms) schizophrenic patients of the disordered and paranoid diagnostic subgroups (DSM-III 295.1 and 295.3), eight severely (HAMD above 35) and eight less severely (HAMD below 20) endogenous depressed patients, and eight control persons using the 133Xe inhalation method in resting condition and during motor activity of the dominant right hand. In all patient groups we found flow activation patterns that were different from those observed in normal control persons. During motor activation in Type I schizophrenics and in less severely endogenous depressed patients, we found a bilateral hyperflow and a diffuse cortical flow increase, also involving deeper cerebral structures. In Type II schizophrenics and severely endogenous depressed patients, however, we found a widespread nonreactivity of the regional cerebral blood flow (rCBF) to motor activation, with no flow increase in the contralateral primary motor area. In normal control individuals, we reproduced a 25% flow increase that was strictly limited to the contralateral primary motor area, as already reported by other authors. As only the schizophrenic patients were not under antipsychotic medication (4 with a washout of at least 1 week prior to the investigation, 12 never treated with drugs before), contaminating effects of the medication cannot be ruled out for the endogenous depressed patient groups. However, in schizophrenic patients, these results suggest a diffuse disorganization and lack of laterality of motor functional systems. In addition, the change from hyperactivity to hyporeactivity might indicate cerebral functional correlates of the change from Type I to Type II symptomatology in schizophrenic patients, which could possible prove to be of clinical importance.