Introduction: Space and motion discomfort (SMD) refers to various symptoms that occur in environments with unreliable visual and kinesthetic information that do not permit adequate spatial orientation. Some studies have demonstrated that there is a stable and predictable relationship between vestibular dysfunction and anxiety disorders. Further, vestibular dysfunction can predispose or trigger the development of panic disorder with or without agoraphobia (PD/A) or reinforce phobic avoidance. It therefore seems clinically useful to develop and validate instruments for evaluating SMD in various populations. Measuring SMD could facilitate identification of individuals with PD/A who present comorbid vestibular dysfunction. Jacob et al. developed and validated such a questionnaire: the Situational characteristics questionnaire (SitQ). This questionnaire evaluates the presence of symptoms such as dizziness, vertigo, and instability under specific conditions. The SitQ comprises two subscales that measure SMD and one subscale (agoraphobia) that measures agoraphobic avoidance behaviours. The instrument has two sections. The first section is composed of the SMD-I and agoraphobia subscales, containing 19 and seven items, respectively. Each item consists of two contrasting descriptors of a specific situation or environment. The respondent is required to indicate to what extent the two described situations or environments cause discomfort. Each item includes a "criterion" descriptor for the situation (i.e., a descriptor that is presumed to engender SMD) and an alternative (non-criterion) descriptor. The second section comprises the SMD-II scale; this scale is composed of nine criterion situations, for which non-criterion situations are not supplied. The instrument takes approximately 20 minutes to complete.

Objective: The present study focuses on the validation of the French-language version of the SitQ: the questionnaire des caractéristiques situationnelles (QCS).

Method: The sample was composed of French Canadians recruited across Quebec from an anxiety disorders treatment clinic, general psychiatric care clinics, a community organization for individuals with anxiety disorders, advertisements in local newspapers, and ads posted in various public locations. The sample included 141 participants who met the criteria for lifetime PD/A. Participants reported current PD/A (n=73) or PD/A in remission (n=68). The control sample was recruited from undergraduate courses in various disciplines. Two hundred and thirty-five (n=235) students completed the questionnaires. Data from 63 (26.8%) participants were excluded from the analyses due to failure to complete all of the research questionnaires.

Results: Analysis of the global descriptive data and the descriptive data for each dependent variable revealed that the data were independent of sociodemographic variables and respected the assumptions of normal distribution (skewness and kurtosis). Parametric tests were subsequently conducted. Using the combined data from the control and clinical groups, the internal consistency of the scales was analyzed using Cronbach's alpha. The SMD-I and SMD-II scales demonstrated good homogeneity. The results were comparable or superior to those obtained with the English-language version of the questionnaire. The agoraphobia scale demonstrated weaker internal consistency and corresponding weaker homogeneity. This result was consistent with that of the original version of the agoraphobia scale; this scale was eliminated for the subsequent analyses. Construct validity was analyzed via t-tests comparing clinical and control groups. Effect sizes were estimated using percentage of variance explained. The SMD-I scale demonstrated weak construct validity and was also eliminated from subsequent analyses. The SMD-II scale demonstrated good construct validity and provided an adequate measure of the theoretical construct of SMD. This scale permitted discrimination of participants according to the presence or absence of PD/A. It is therefore possible to identify participants with PD/A by their level of SMD. This result is comparable to that of Jacob et al.

Conclusion: The results of the present study are generally consistent with the results of the validation of the original version of the questionnaire. However, the SMD-I and agoraphobia scales in the French-language version of the measure did not achieve a level of significance sufficient to definitively establish validity.