Using virtual reality technology for exposure therapy to treat patients with anxiety disorders is attracting considerable research attention. The ability to monitor patient anxiety level helps therapists to set appropriate anxiety arousing situations. Physiological measure has been put forward as objective indicator of anxiety levels. Because of individual variation, they need a baseline recording which is often conducted in neutral virtual world which does not include phobic stressors. Still because of the novelty of the virtual world, reports in the literature suggest that individuals already show some level of arousal when placed in these worlds. This paper presents two studies which look at the effect two different neutral virtual worlds can have on individuals. Findings suggest that a neutral world does not have to result in an increased level of arousal.

Objective
The nature of the relationship between physiological and subjective responses in phobic subjects remains unclear. Phobics have been thought to be characterized by a heightened physiological response (physiological perspective) or by a heightened perception of a normal physiological response (psychological perspective).
Method
In this study, we examined subjective measures of anxiety, heart rate (HR), and cardiac autonomic responses to flight-related stimuli in 127 people who applied for fear-of-flying therapy at a specialized treatment center and in 36 controls without aviophobia.
Results
In keeping with the psychological perspective, we found a large increase in subjective distress (η2=.43) during exposure to flight-related stimuli in the phobics and no change in subjective distress in the controls, whereas the physiological responses of both groups were indiscriminate. However, in keeping with the physiological perspective, we found that, within the group of phobics, increases in subjective fear during exposure were moderately strong coupled to HR (r=.208, P=.022) and cardiac vagal (r=.199, P=.028) reactivity. In contrast to predictions by the psychological perspective, anxiety sensitivity did not modulate this coupling.
Conclusion
We conclude that subjective fear responses and autonomic responses are only loosely coupled during mildly threatening exposure to flight-related stimuli. More ecologically valid exposure to phobic stimuli may be needed to test the predictions from the physiological and psychological perspectives.

Physiological sensations and discomfort constitute the major symptoms reported by aviophobics. Anxiety sensitivity (AS) seems to moderate the relationship between self-reported somatic sensations and flight anxiety, and AS has been identified as a vulnerability factor for flight phobia. In this study we examined whether AS moderates the effects of somatic sensations and autonomic nervous system reactivity on flight anxiety induced by real flight. In fifty aviophobics participating in Cognitive Behaviour Group Therapy (CBGT), flight anxiety, somatic sensations and autonomic nervous system reactivity were assessed during a guided return flight. Results indicate that physiological reactivity interacted with AS. Changes in heart rate and parasympathetic activity were more strongly associated with changes in reported flight anxiety for high AS participants, and less for participants low on AS. Results did not indicate a moderating effect of AS on the relationship between self-reported somatic sensations and flight anxiety. Our results suggest that therapy for flight phobia might benefit from addressing the physical effect of anxiety, by means of cognitive restructuring and exposure to interoceptive stimuli, particularly in aviophobics high in AS.

Objectives 
Exposure is regarded to be a crucial component of therapies for phobias. According to emotional processing theory, the success of exposure therapy is predicted by activation of subjective and physiological fear responses and their within-session habituation and between-session adaptation. This study tested this prediction for aviophobia.
Methods 
Seventy-nine participants following a highly standardized treatment program for aviophobia provided self-reported and physiological (heart rate, respiratory sinus arrhythmia and pre-ejection period) measurements of fear activation, within-session habituation, and between-session adaptation during exposure to flight-related stimuli, a flight simulator, and during two real flights. Multiple regression analyses were conducted to examine whether these measurements predicted therapy outcome up to 3 years after finishing therapy, including number of flights flown in this period.
Results 
Both subjective and physiological arousal measurements indicated strong fear activation and large within-session habituation and between-session adaptation during exposure. Flight anxiety measures showed large improvements up to 3 years after treatment (η2 between 0.72 and 0.91). Lower self-reported anxiety during flight exposure was associated with lower flight anxiety after exposure (R2 = 0.15) and more flights flown (R2 = 0.14). Within-flight habituation or between-session adaptation of self-reported anxiety had no relationship with treatment outcome. Within-flight habituation of HR reactivity (R2 = 0.10) and respiratory sinus arrhythmia reactivity (R2 = 0.11) was associated with lower flight anxiety directly after the flight, but not on flight anxiety 3 years after finishing therapy or on long-term flying behavior.
Conclusions 
The results provide only weak support for emotional processing theory. Low self-reported anxiety during in vivo flight exposure was the best predictor of successful long-term therapy outcome.

Background and objectives
Emotion can be seen as the organizing process that coordinates response systems to deal effectively with challenges and opportunities. Synchronous change in subjective and physiological reactivity is regarded as an indication of this organizing process. Synchrony is expected to increase with the intensity of emotional stimuli. Conversely, adaptive emotional functioning could be indicated by progressive synchrony upon increasing demands, and the magnitude of synchrony could be an indication of progress during therapy.
Methods
We examined whether synchronous change in subjective and physiological reactivity over repeated exposures increased from watching a flight video through simulated flight to actual flight, and whether the magnitude of synchronous change predicted favourable short- and long-term treatment outcome within a group of 77 aviophobic participants during CBT.
Results
Results did not show a relationship between the intensity of the phobic stimuli and the magnitude of synchronous change in subjective and physiological reactivity. Moreover, synchronous change across both response systems did not predict treatment outcome.
Limitations
By design this study had no control group. Additional treatment or life events between end of treatment and 3-year follow-up were not assessed.
Conclusion
The results provide only weak support for the functionalistic view that successful treatment of anxiety disorders is indicated by synchronous change in reactivity across emotional response systems. The relationship between these systems is likely to be affected by many intervening variables including higher order cognitive processes.