8 Reasons for this discrepancy to our results with the German Q18 might—besides the modification of the questionnaire—be different diagnostic procedures or the chosen cut off point.
In three studies the exposed group had higher Q16 scores than the controls but the difference was not significant.7 20 21 In another investigation there was no consistent increase in the Q16 score in four different exposure groups.6 In only two studies (10%) did the controls have a slightly higher Q16 score than the exposed workers.22 24 Therefore it can be concluded that both questionnaires, the Swedish Q16 and the German Q18, show similar results as a screening instrument for neurotoxic symptoms in workers exposed to solvents.