Body-maps of emotions in bilateral vestibulopathy

Patients with a bilateral vestibulopathy (BVP) report a poorer quality of life, in both its physical and social dimensions, than healthy control participants [1]. BVP patients may report spatial anxiety with deficits in spatial cognition [2], and abnormal autonomous regulation [3]. Yet, they have lower anxiety related to vertigo [4] and less psychiatric comorbidities [5] than most patients with episodic vertigo. How BVP patients experience emotions—other than anxiety and depression—in an embodied way, is poorly documented, despite evidence of tight connections between vestibular, emotional, and embodiment processes [6]. Here, we investigated the embodiment of emotions in BVP patients. Emotions are strongly embodied: happiness, sadness and fear, for example, are associated with a variety of physiological changes [7] involving the interoceptive and somatosensory systems [8]. We used the computerized emBODY tool [9, 10] to document body-maps of emotions in BVP patients and healthy controls. Experiments with the emBODY tool in large samples of healthy participants revealed that different emotions are consistently associated with different bodymaps [9, 10]. These body-maps of emotions are consistent across different cultures [9], developed between age 6 and 17 to become spatially specific [11], and they appear to be altered in clinical conditions [12]. We tested 21 BVP patients and 21 healthy controls matched for age, sex, education, and body-mass index (Table 1). Anxiety and depression [13] did not differ between groups. Standard otoneurological examinations established that patients presented a severe bilateral vestibular hypofunction without neurological disorder (Table 1). Controls reported no history of otoneurological disorder. Participants reported the bodily sensations associated with a neutral state, their current state, four basic emotions (fear, anger, disgust, happiness), and four non-basic emotions (anxiety, love, depression, pride). Each emotional word was presented once in a randomized order. Participants indicated where exactly in their body and how intensely they perceived an increase or decrease in activation when experiencing that emotion by coloring 2D human silhouettes on a computer screen (see Fig. 1a for details on procedures). Increase or decrease in activation was meant to reflect changes in interoceptive signals, such as higher/lower heart and breathing rates, palm sweating, skin temperature, or tonus in the legs and facial musculature. Thus, all sensed and reported changes in such inner bodily signals (no matter if the feeling is of activation or deactivation) would correspond to high interoception (i.e., awareness of inner bodily states). First, individual maps were averaged to generate group body-maps representing the mean intensity of reported emotions for patients and controls [9, 10] (Fig. 1b). Visual inspection of group body-maps showed lower activation for positive emotions (e.g., happiness, pride, love), and lower Bigna Lenggenhager and Christophe Lopez share last authorship. These authors contributed equally to the present study.