Verification of the Psychometric Characteristics of the Nijmegen Questionnaire for the Diagnosis of Dysfunctional Breathing During the COVID-19 Pandemic on a Russian Sample

Abstract

The purpose of the study was to check the psychometric properties of the Nijmegen questionnaire (NQ) (Van Dixhoorn, Duivenvoorden, 1985), aimed at diagnosing the presence of signs of dysfunctional breathing (DВ) according to self–reports of respondents in the conditions of the COVID-19 pandemic in a Russian-speaking sample. The study sample consisted of 1 362 respondents (1 153 women and 209 men) aged 18 to 88 years (mean age 38.3±11.4) who filled out an online questionnaire from April to December 2020 during the COVID-19 pandemic. The following methods were used to test the construct validity of the Russian version of the NQ: 1) Perceived Stress Scale-10 (PSS-10; Ababkov et al., 2016); 2) State-Trait Anxiety Inventory (STAI, Khanin, 1976), the scales of which were modified to measure the level of anxiety during a pandemic (State anxiety) and before the pandemic (Trait anxiety) (Pervichko et al., 2020); 3) The Symptom Check List-32 (SCL-32) (Mitina, Gorbunova, 2011); (4) An abridged version of the Six-Factor Personality Inventory HEXACO-24 (Egorova et al, 2019). The study participants also completed a socio-demographic questionnaire (Pervichko et al., 2020). The results of checking the Russian-language version of the NQ for reliability are presented: the value of the internal consistency coefficient α-Cronbach for the integral indicator = 0.877. Four subscales were identified, the indicators of which improved when the questionnaire was reduced to 10 points. Internal convergent and discriminant validity has been verified for the abridged version. The external constructive validity of the questionnaire is proved. High rates of correlation with stress, situational and personal anxiety, as well as other symptoms of psychological distress were revealed. In addition, a high correlation with emotionality has been established. The problem of the "threshold" value of NQ required to identify the formed symptom complex of DB is discussed. The prevalence of DB symptoms before and during the pandemic was compared. A significant difference in the indicators on the scale for men and women was established. Using the obtained Russian-language version of NQ, it was shown that in the conditions of the COVID-19 pandemic, 27.7% of the study participants who were not sick with COVID-19 showed signs of a formed DB symptom complex, which is more than twice higher than the population indicators in the pre-pandemic period. The frequency of occurrence of the holistic symptom complex of DB in women is three times higher than in men: 31.0% vs 9.1% (p<0.001). The results of the study allow us to conclude that NQ is a reliable and valid tool for diagnosing the severity of DB symptoms, which can be recommended for use as an express diagnostic tool for the presence of psychogenically caused respiratory disorders in persons complaining of "difficulty breathing" in the absence of objective grounds.