Although functional magnetic resonance imaging (fMRI) has gained increasing importance in investigating neural substrates of anxiety disorders, less is known about the stress eliciting properties of the scanner environment itself. The aim of the study was to investigate feasibility, self-reported distress and anxiety management strategies during an fMRI experiment in a comprehensive sample of patients with panic disorder and agoraphobia (PD/AG). Within the national research network PANIC-NET, n = 89 patients and n = 90 controls participated in a multicenter fMRI study. Subjects completed a retrospective questionnaire on self-reported distress, including a habituation profile and exploratory questions about helpful strategies. Drop-out rates and fMRI quality parameters were employed as markers of study feasibility. Different anxiety measures were used to identify patients particularly vulnerable to increased scanner anxiety and impaired data quality. Three (3.5%) patients terminated the session prematurely. While drop-out rates were comparable for patients and controls, data quality was moderately impaired in patients. Distress was significantly elevated in patients compared to controls; claustrophobic anxiety was furthermore associated with pronounced distress and lower fMRI data quality in patients. Patients reported helpful strategies, including motivational factors and cognitive coping strategies. The feasibility of large-scale fMRI studies on PD/AG patients could be proved. Study designs should nevertheless acknowledge that the MRI setting may enhance stress reactions. Future studies are needed to investigate the relationship between self-reported distress and fMRI data in patient groups that are subject to neuroimaging research.
Although functional magnetic resonance imaging (fMRI) has gained increasing importance in investigating neural substrates of anxiety disorders (Paulus, 2008), less is known about the stress eliciting properties of the scanner environment itself. Reports about routine care patients indicate that an MRI examination can produce subjective distress (Dantendorfer et al., 1997, Flaherty and Hoskinson, 1989, Kilborn and Labbe, 1990, Mackenzie et al., 1995 and McIsaac et al., 1998) or trigger long-term claustrophobia (Fishbain et al., 1988 and Kilborn and Labbe, 1990) and panic attacks (Spiegelhalder et al., 2009) in subjects with no previous psychiatric history. Pre-existing claustrophobia may moreover predict distress and panic symptoms in the scanner (McIsaac et al., 1998). Adverse reactions not only constitute a significant problem for patients: they can affect the performance of (f)MRI studies by increasing the number of declined appointments, premature terminations of scans, or impair data quality (Dantendorfer et al., 1997).
Scanner distress ranges from moderate apprehension (approx. 30%), to severe panic and claustrophobia experienced by 5–10% of routine care patients (Melendez and McCrank, 1993). Among anxiety patients, those suffering from panic disorder and agoraphobia (PD/AG) are particularly vulnerable to the stress eliciting properties of the MRI, which is a highly agoraphobic/claustrophobic stimulus. Comprehensive assessments of scanner distress in PD are still lacking, but Bystritsky et al. (2001) found elevated panic symptoms in patients compared to controls. Maddock et al. (2003) stated that four out of six patients reported feeling anxious throughout the scan. Pillay et al. (2006) observed that although all eight patients were able to complete the scan, they showed initial signs of hesitation. Interpretation of these observations is however limited by the small number of patients and lack of quantitative assessment tools.
The aim of the present study was to investigate scanner-related effects on self-reported distress and data quality in a multicenter fMRI study on n = 89 PD/AG patients, addressing the following research questions:
1)
Are large-scale fMRI studies in PD/AG patients (dropout-rates, data quality) feasible?
2)
Do patients and controls differ in their amount of distress before, during and after the session?
3)
Can we identify vulnerable patients using different measures of anxiety?
4)
Management strategies: what can we do to make patients feel more comfortable?
