Anxiety sensitivity and the auditory perception of heartbeat

Anxiety sensitive (AS) individuals tend to fear sensations associated with autonomic arousal. AS has been associated with panic disorder and has predicted the onset of panic attacks. Panic patients often rate cardiac symptoms as the most fearful sensations experienced during a panic attack. It follows that AS individuals may also use different strategies when making decisions about feared sensations. Indubitably, misses and false alarms have different consequences. With these principles in mind, we developed a signal detection paradigm using normal and abnormal heartbeat sounds to investigate the strategies high and low AS individuals apply when making choices about cardiac sounds. Participants were 65 college students scoring high (≥24) or low (≤14) on the Anxiety Sensitivity Index. Participants completed three signal-in-white noise detection tasks, where signals were neutral tones, normal heartbeats, or abnormal heartbeats, and a discrimination task, where signals were normal and abnormal heartbeats. Methods of signal detection theory (SDT) were used to calculate response indices of correction detection, false alarm, sensitivity, and response bias. As hypothesized, high AS and low AS listeners used different response patterns for tasks involving fear-relevant auditory stimuli, but not for neutral tones. Compared to low AS individuals, high AS individuals demonstrated a greater propensity to report the presence of normal, but not abnormal, heartbeat sounds. Furthermore, high AS was not associated with a lower criterion for selecting "abnormal" in a task requiring the discrimination between normal and abnormal cardiac sounds. High and low AS individuals did not differ in their sensitivity to normal heartbeats; however, high AS individuals consistently demonstrated lower sensitivity on tasks involving abnormal heartbeats. AS was characterized by an elevated false alarm rate across all heartbeat tasks. These results suggest that abnormal heartbeats may activate meanings of "threat" in AS individuals, which may interfere with the ability to selectively attend to tasks involving threat signals. If AS individuals do not create a well-elaborated and accurate representation of the abnormal heartbeat stimuli, then they also may have a more difficult time detecting abnormal heartbeats among other stimuli (e.g., white noise, normal heartbeats). High AS individuals may also consider it less costly to falsely detect a heartbeat than to miss a heartbeat, and might therefore choose a more lax criterion when responding to a perceived threat. High AS individuals did in fact evidence a lower criterion than low AS individuals when responding to normal heartbeats. However, contrary to our expectation, this strategy shifted in the opposite direction in response to abnormal heartbeat sounds. High AS individuals may have shifted their response criterion for abnormal stimuli in an effort to compensate for a generally known tendency to "cry wolf." High AS individuals may exhibit enhanced activation of threat in the presence of abnormal heartbeats, resulting in decreased performance. However, during the strategic phase of processing (i.e., choosing between "yes" or "no" responses), high AS individuals may actually inhibit their preferred pattern of anxious responding.