Semiology of Atypical Bodily Experiences

The number of multidisciplinary specialists dealing with questions relating to the body has grown steadily over the decades. Dozens of body-related disorders have been described over the years in the fields of neurology, neuropsychology, and psychiatry. These disorders can be grouped under the name "atypical bodily experiences," namely, any experience involving the body (one's own body or the body of another) that appears strange or unusual to the person experiencing it or to those around them. However, despite its probable involvement in human cognition, bodily experience remains a poorly investigated topic in research and clinical practices. The aim of this article is therefore to centralize and provide readers with the conceptual and semiological vocabulary required for the clinical interview, observation, and assessment of atypical bodily experiences. More than 90 of these experiences are defined and grouped into a few broad categories ranging from elementary sensory disorders to higher order neuropsychological or psychiatric symptoms and syndromes. These categories include abnormal sensations (i.e., sensory deficits and related disorders), abnormal perceptions (i.e., abnormal subjective experiences involving the body, autoscopic phenomena, and sensations of presence), identification disorders (i.e., difficulties identifying body parts or people), representation disorders (i.e., difficulties locating body parts, atypical ownership experience, and alterations to body unity), agency disorders (i.e., loss of sense of agency and unintentional motor acts), affective disorders (i.e., anxiety and negative value attributed to one's own body), and interpersonal disorders (i.e., symptoms involving the body but that only become apparent in relation to others).