Signal detection theory and vestibular thresholds: I. Basic theory and practical considerations

Detection theory has been applied to the measurement of vestibular thresholds and vestibular sensory integration. Yet, a formal detection theory analysis of vestibular responses has not been published. Such a de novo analysis seems warranted because the vestibular system has characteristics that differ from other sensory systems, which impacts the application of detection theory. For example, the physical stimuli evoking vestibular responses are typically bidirectional (e.g., leftward/rightward); this bidirectional nature of vestibular responses leads to another characteristic-what is sometimes called vestibular bias-that must also be considered, since it can impact threshold measurements, including thresholds found using staircase procedures. This paper develops a basic model of vestibular noise and then analyzes this model for four standard paradigms-one-interval recognition, one-interval detection, two-interval detection, and two-interval recognition. While any of these paradigms might be justified for a specific application, it is concluded that one-interval recognition paradigms have advantages over other paradigms for many vestibular applications. One-interval recognition is favored over one-interval detection because it lends itself to a fixed detection boundary, is more efficient, and is less impacted by device vibration. One-interval recognition is generally favored over two-interval recognition because it assesses vestibular bias and can require substantially less time than two-interval tasks.