The effects of self-report rating scales on the assessment of motion sickness.

The assessment of motion sickness typically relies on self-reports. It is unclear whether rating general sickness (e.g., Fast Motion Sickness scale; FMS) or specific symptoms (e.g., Motion Illness Symptoms Classification; MISC) impacts the assessment. Different from prior studies, we investigated how FMS and MISC ratings developed during the same motion exposure. Both scales showed comparable time courses with a similar direction of rating transitions. To investigate the development of nausea versus non-nausea symptoms, participants also rated the MISC2D - a two-dimensional MISC-derivative separating these symptoms - alternatingly with the FMS in another exposure. We found no clear reduction in general sickness or non-nausea symptoms at nausea onset. Nausea-related symptoms, starting with stomach awareness, preceded non-nausea symptoms in over half our sample. Although we did not intend the MISC2D as a new scale, it proved suitable for repeated administration while capturing distinct motion sickness aspects.