Franz Mueller-Spahn

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.

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.

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.

Three-Dimensional Virtual Reality as a Tool in Cognitive-Behavioral Therapy of Claustrophobic Patients

At present we are conducting a control group-controlled multimodal study, using a three-dimensional virtual environment as a therapeutical tool. Monitoring includes measurement of psychopathological, neurobiochemical, and neurophysiological parameters. In particular, this study is aimed to explain, whether 3D VEs can be used to treat claustrophobia on the one hand for stimulus presentation, on the other hand as a therapeutically useful exposure environment. First, a pilot study was conducted in 1997, in which 13 healthy subjects and two claustrophobic patients were examined concerning the question, whether during an uninterrupted exposure time of 45 min, there were significant variations of the measured physiological parameters and related side effects or side effects subjectively impairing the subjects. We concluded from the results of that investigation, that a 45-min expodure, as far as the tested subjects were concerned, cannot be regarded as anxiety- or stress-inducing in itself.

Monitoring Human-Virtual Reality Interaction: A Time Series Analysis Approach

Optimization of Virtual Environments (VEs) in the Mental Health field as well as in other application areas depends heavily on the exact knowledge of the technologys impact on mental work load, st...

A Rapid Prototyping Framework for the Development of Virtual Environments in Mental Health

Virtual Environments (VEs) can be used as a tool for the analysis of mental parameters as well as for therapy of special mental disorders. The framework allows the rapid development of virtual envi...

Multichannel near-infrared spectroscopy: data evaluation by means of time series analysis

We used near infrared spectroscopy (NIRS) to study non- invasively changes in cerebral hemoglobin oxygenation during performance of a verbal fluency task in healthy volunteers (n equals 19). We used a multichannel system combining six commercially available NIRS devices (NIRO-500, Hamamatsu Photonics) that allows measurements over the left and right frontal, parietal and occipital cortex simultaneously. We described the NIRS variables both in the time- and frequency-domain using digital signal processing. In the time-domain we measured the blood flow response by calculation of concentration changes for oxygenated and deoxygenated hemoglobin (HbO2, HbR) and their latency to stimulus variations. We applied frequency selective filters and found an increase of the global signal variability during cognitive stimulation. These effects can be visualized by spectral analysis. The powerspectras of the optical signal varied clearly with rest and activity states and showed a different spectral distribution over the frontal as compared to the parietal cortex.