Research on posttreatment return of claustrophobic fear, arousal, and avoidance using mock diagnostic imaging

Review of claustrophobia incidence in MRI: A service evaluation of current rates across a multi-centre service

INTRODUCTION

Magnetic Resonance Imaging remains an anxious experience for many, often exhibiting as fear of enclosed spaces. A useful metric to assess its prevalence and impact in practice is premature termination due to claustrophobia. Incidence varies and depends on many factors such as the physical nature of the imaging equipment and examination being undertaken, as well as the patient themselves.

METHODS

Scan appointment data from between April 2019-March 2021 was extracted and reviewed. Analysis included the type of scanner used, patient age, sex, examination area, funding source, attendance and completion status. Binomial logistic regression was performed to look for any relevant predictors of failure to scan due to claustrophobia.

RESULTS

Overall incidence of incomplete examinations due to claustrophobia was 0.76%. Whilst the majority of scans were performed on conventional systems, those undergoing Open scans were over three times more likely to fail a scan due to claustrophobia, whilst those undergoing UpRight scanning were half as likely. Likelihood of claustrophobia increases with females, those between 45-64years of age, funded by the NHS and entering the scanner head first or having a head scan.

CONCLUSION

Incidence of incomplete scanning is below 1% but with the potential for further reduction with implementation and use of improved scanner design and technology. Understanding the impact of other variables is also useful to raise awareness of those at greater risk of claustrophobia. However, there are wider influences beyond data alone to consider and account for.

IMPLICATIONS FOR PRACTICE

Whilst occurrence of claustrophobia is low, there remains a cost impact, as well as an importance in understanding the patient experience. Drawing on operational data can help provide a limited, generalised view to support service improvement.

Anxiety in Cancer Patients during 18F-FDG PET/CT Low Dose: A Comparison of Anxiety Levels before and after Imaging Studies

Objective. Assessing the level of anxiety in oncology patients who underwent ¹⁸F-FDG PET/CT low dose scan and identifying the main reasons that generate anxiety. Material and Method. The study included 81 cancer patients submitted to the ¹⁸F-FDG PET/CT low dose scan. Patients filled in the Scan Experience Questionnaire and the State-Trait Anxiety Inventory (STAI) before and after ¹⁸F-FDG PET/CT low dose scan. Results. Substantial levels of anxiety were detected both before and after ¹⁸F-FDG PET/CT low dose scan (STAI mean > 30), with a significant increase in the state of anxiety after scan performance (p < 0.0001, Median_pre = 31.1, and Median_pos = 33.0). ¹⁸F-FDG PET/CT low dose results are the main cause of anxiety both before (79.1%) and after (86.9%) the scan. The information provided by staff both before and on the ¹⁸F-FDG PET/CT low dose day was classified mostly as completely understandable (70.5% and 75.3%, resp.) and as very useful (70.5% and 72.6%, resp.) and correlated positively with patients' overall satisfaction with NM Department (r_S = 0.372, p = 0.004 and r_S = 0.528, p = 0.000, resp.), but not with anxiety levels. Conclusions. Patients perceive high levels of anxiety during the ¹⁸F-FDG PET/CT low dose scan and the concern with scan results was pointed out as the main factor for that emotional reaction.

Optimal attentional focus during exposure in specific phobia: a meta-analysis

Over the last 30 years, researchers have disagreed over the consequences of diverting attention from threat for exposure efficacy, which is an important theoretical and clinical debate. Therefore, the present meta-analysis assessed the efficacy of attentionally focused exposure against distracted and attentionally uninstructed exposure regarding distress, behavioral, and physiological outcomes. We included 15 randomized studies with specific phobia, totaling 444 participants and targeting outcomes at post-exposure and follow-up. Results indicated no difference between the efficacy of distracted exposure as opposed to focused or uninstructed exposure for distress and physiology. For behavior, at post-exposure, results were marginally significant in favor of distracted as opposed to focused exposure, while at follow-up results significantly favored distraction. However, concerning behavior, uninstructed exposure was superior to distraction. Moderation analyses revealed that, regarding distress reduction and approach behavior, distracted exposure significantly outperformed focused exposure when the distracter was interactive (g=1.010/g=1.128) and exposure was spread over the course of multiple sessions (g=1.527/g=1.606). No moderation analysis was significant for physiological measures. These findings suggest that distraction during exposure could be less counterproductive than previously considered and even beneficial under certain circumstances. Theoretical implications and future directions for research are discussed.

Within and between session changes in subjective and neuroendocrine stress parameters during magnetic resonance imaging: A controlled scanner training study

Accumulating evidence suggests that the magnetic resonance imaging (MRI) scanner can act as a stressor, eliciting subjective and neuroendocrine stress responses. Approaches to familiarize subjects with the scanner could help minimizing unintended effects on neural activation patterns of interest. Controlled studies on the effects of a scanner training are however missing. Using a comparative design, we analyzed within- and between session changes in subjective and neuroendocrine stress parameters in 63 healthy, scanner-naïve adults who participated in a two-day training protocol in an MRI, mock, or lab environment. A habituation task was used to assess within-session changes in subjective and neuroendocrine (cortisol) stress parameters; between-session changes were indicated by differences between days. MRI and mock, but not lab training were successful in reducing subjective distress towards the scanner. In contrast, cortisol reactivity towards the training environment generally increased during day 2, and the percentage of cortisol responders particularly rose in the mock and MRI groups. Within-session habituation of subjective arousal and anxiety was observed during both days and irrespective of training condition. Present findings demonstrate that training in a scanner environment successfully reduces subjective distress, but may also induce sensitization of endocrine stress levels during repeated scanning. Subjective distress can further be stabilized by acclimating subjects to the environment prior to the MRI assessment, including a short habituation phase into the assessment protocol. If replicated, present findings should be considered by researchers employing repeated measurement designs where subjects are exposed to a scanner more than once.

Reinstatement of fear in humans: autonomic and experiential responses in a differential conditioning paradigm

The present study investigated reinstatement of fear in humans using an aversive differential conditioning paradigm. Two neutral human face pictures were presented during habituation, acquisition, extinction, and postreinstatement phases. One picture served as a conditioned stimulus (CS) reinforced by an unconditioned stimulus (US) in the form of electrical stimulation (CS+) and the second picture as a control stimulus that was never reinforced (CS-). The prediction that in a reinstatement manipulation a previously extinguished fear response in humans can be reinstated in a reinstatement group by the mere presentation of three unpredicted electrical stimulations (USs) was tested. Participants in the control group were not exposed to unpredicted USs and no reinstatement effect was expected. Outcome measures included subjective US expectancy ratings and skin conductance responses. Results showed non-selective return of the fear response due to fear recovery associated with both CSs (CS+/CS-) in the reinstatement group. Unexpected fear recovery was observed for both CSs (CS+/CS-) in control participants. Results are discussed with respect to context conditioning, fear generalisation, and anxiety-related cognitive mechanisms underlying fear recovery after extinction.

Reactions of young children to the MRI scanner environment

Seventy children aged 2 to 7 years were exposed to the MRI environment through a series of steps typical of a research study. Their willingness to proceed through the process was used to estimate the prevalence of fear. Thirty-seven children (53%; 95% confidence interval [41%, 65%]) completed the approach sequence. Although the correlation of child age in months (Mean (M) = 60.1, standard deviation = 16.5, N = 70) and highest successful step (M = 5.8, standard deviation = 2.6, 95% confidence interval [5.2, 6.4]) completed was not statistically significant at the 0.05 level, r (68) = 0.21, P = 0.08, 95% confidence interval [-0.03, 0.42], the proportion of children aged 6-7 years who successfully completed all steps (14 of 21, 67%, 95% confidence interval [50%, 84%]) was significantly different from the proportion of children aged 2-3 years who completed all steps (six of 23, 26%, 95% confidence interval [11%, 41%]) (Fisher's exact test, two-tailed P = 0.0148). A failure rate of at least 50% should be included into group size calculations when performing studies with young children (2-7 years), in addition to motion and other experimental factors.

MRI-related anxiety levels change within and between repeated scanning sessions

Magnetic resonance imaging (MRI) scans frequently trigger state anxiety in individuals being scanned. It is not known, however, whether levels of MRI-related anxiety change over the course of a single scan or across repeated scanning experiences. Since changes in state anxiety are known to affect regional brain activity in healthy volunteers, systematic changes in levels of MRI-related anxiety could confound findings from neuroimaging studies. We assessed anxiety levels in eleven healthy male volunteers during a control period and during two MRI scanning sessions. Anxiety levels were highest during the first MRI scan, dropping to control levels or below by the second scan. In addition, anxiety fluctuated within scanning sessions, particularly during the first scan, with levels high at the beginning of the session, decreasing during mid-scan and then increasing again toward the end of the session. These results suggest that habituation in an MRI simulator before participating in a neuroimaging study could help to decrease fluctuations in MRI-related anxiety. Moreover, in studies that address several experimental questions within a single scanning session, experimental designs could be adapted to avoid potential confounds from within-scan variation in scanner-related anxiety.

Relapse of successfully treated anxiety and fear: theoretical issues and recommendations for clinical practice

Despite the existence of effective interventions for anxiety disorders, relapse--or the return of fear--presents a significant problem for patients and clinicians in the longer term. The present paper draws on the experimental and clinical behavioural literature, reviewing the mechanisms by which the return of fear can occur. The aim of the paper was to generate a list of treatment recommendations for clinicians aimed at reducing relapse in successfully treated anxiety disorders. Clinical and experimental literature on the mechanisms of renewal, reinstatement, spontaneous recovery and reacquisition are reviewed. These are linked with the clinical and experimental literature on the return of fear in successfully treated anxiety. A list of recommendations to assist in reducing the probability of relapse in successfully treated anxiety is presented. This list includes methods for use in behavioural (exposure) treatment of anxiety disorders that aim to enhance clinical outcomes. Despite the significant problem of relapse in successfully treated anxiety, there are methods available to reduce the probability of relapse through return of fear. Clinicians engaging in treatment of anxiety disorders should be mindful of these methods to ensure optimal patient outcome.

Component fears of claustrophobia associated with mock magnetic resonance imaging

A conceptualization of claustrophobia [Rachman, S., & Taylor, S. (1993). Analyses of claustrophobia. Journal of Anxiety Disorders, 7, 281-291] was evaluated in the context of magnetic resonance imaging. One hundred eleven students responded to questionnaires that quantified fear of suffocation, fear of restriction, and sensitivity to anxiety symptoms. Sixty-four of them were then exposed to a mock magnetic resonance imaging assessment; maximum subjective fear during the mock assessment was self-reported, behavioral reactions to the mock assessment were characterized, and heart rates before and during the assessment were recorded. Scores for fear of suffocation, fear of restriction, and anxiety sensitivity were used to predict subjective, behavioral, and cardiac fear. Subjective fear during the mock assessment was predicted by fears of suffocation and public anxiousness. Behavioral fear (escape/avoidance) was predicted by fears of restriction and suffocation, and sensitivity to symptoms related to suffocation. Cardiac fear was predicted by fear of public anxiousness. The criterion variance predicted was impressive, clearly sufficient to legitimize both the research preparation and the conceptualization of claustrophobia that was evaluated.

Return of fear in a human differential conditioning paradigm caused by a return to the original acquistion context

In a differential human fear conditioning paradigm evidence for ABA-renewal was obtained manipulating the lighting in the experimental room. During acquisition in either a dark or illuminated room, one neutral slide was sometimes paired with a loud aversive noise whereas another slide was not. Subsequently, extinction took place in the opposite lighting context. When afterwards the participants were tested again in the original acquisition context, measurements revealed a recovery of the conditioned electrodermal response and an increase in the retrospective verbal US-expectancy ratings. No response recovery was obtained in an AAA-group that received acquisition, extinction and test trials in one and the same context. Several theoretical explanations for this type of return of fear as well as implications for clinical practice are discussed.

Fear responses to mock magnetic resonance imaging among college students: toward a prototype experiment

Two hundred randomly selected student participants (139 females, 61 males) responded initially to questionnaires that quantified variables such as state and trait anxiety, anxiety sensitivity, claustrophobia, and panic/agoraphobia. Later they were informed that a mock magnetic resonance imaging (MRI) procedure was upcoming, and were prompted to provide self-efficacy ratings vis-à-vis completing the procedure. Finally, the participants' behavioral reactions to a mock MRI procedure were characterized; their heart beats were recorded and ratings of fearfulness were acquired. One purpose of the research was simply to tally numbers of participants who responded fearfully in various ways: 7 failed the procedure behaviorally, 7 others completed the procedure but did so fearfully, 17 others completed the procedure but manifested excessive heart-rate responsivity. A second purpose of the research was to "predict" subjects' fear-response categorization psychometrically and/or with self-efficacy ratings: psychometric data related to claustrophobia predicted subjects' fear-response categorization as did self-efficacy ratings. According to these results mock MRI assessment among college students provides a promising context for research on claustrophobia.