Discomfort with space and motion: A possible marker of vestibular dysfunction assessed by the situational characteristics questionnaire

Space and motion discomfort (SMD) refers to the situational specificity of symptoms occurring in some patients with vestibular dysfunction, such as those with balance disorders and some with panic disorder. SMD occurs in situations characterized by inadequate visual or kinesthetic information for normal spatial orientation. We report the results of two studies of the construct validity of the Situational Characteristics Questionnaire (SitQ), which has two subscales, both of which measure SMD: the SMD-I and SMD-II. In Study 1, the SitQ was administered to members of a self-help group for balance disorders, a psychiatric sample consisting of patients with panic disorder, nonpanic anxiety disorders, depression, and a sample of normals. SMD levels were the highest in the self-help balance group, next to the highest in the panic groups, and lowest in the remaining groups. In Study 2, the SitQ was administered to otolaryngological patients with vestibular dysfunction and to patients with hearing loss. SMD levels were higher in the vestibular patients. Data on internal consistency, test-retest reliability, and convergent and discriminant validity are presented. The SitQ, particularly the SMD-II, is recommended for quantifying space and motion discomfort in patients with anxiety and/or balance disorders.Study 1 was funded by MH 40757. Study 2 was funded by a grant from the Upjohn Company and MH 19816.