Revised Imagined Sensation Questionnaire (ISQ): Improved Dimensionality and Reduced Bias

The Exploratory Factor Analysis (EFA) indicated that the primary version of the Imagined Sensation Questionnaire (ISQ), which included 18 items, suffered from poorly defined dimensions. Certain items demonstrated considerable overlap across different dimensions, necessitating a reevaluation and selection of questionnaire items. The criteria for item removal were twofold: (1) Items that provoked strong negative emotions such as fear and disgust were excluded. (2) Items inducing intense itching sensations, which were challenging to imagine due to limited personal experience, were also removed. The rationale behind these exclusions was to (1) minimize the influence of emotions on participant ratings, a key requirement of the ISQ, and (2) mitigate potential biases stemming from rating unfamiliar itching sensations in hypothetical scenarios. Consequently, items I2, I3, I7, I14, and I17 were removed, with the remaining items forming the new version of the ISQ. EFA results for both the original and new ISQ versions are presented in Table 5. Notably, the new ISQ is structured into three distinct dimensions, with each item exhibiting a factor loading greater than 0.5 within its respective dimension and no cofactor issues. Furthermore, the cumulative explained variance for the three dimensions in the new ISQ is 63.68%, a significant improvement over the original ISQ (see Table 4 for comparison). This revised version provides a more robust and reliable measure of imagined sensations.