Although the Swedish Q16 and the German Q18 are different questionnaires, they share 13 questions. We therefore conducted a literature search which identified 21 relevant studies that used the Swedish Q16 in workers exposed to
solvents. Their main results are presented in table 4.
Overall estimation shows that the Swedish Q16 was sensitive in identifying effects induced by solvents in 15 out of 21 studies (71%). Thus the main results of most of these studies correspond with our findings on the German
Q18. Despite significant effects on a group basis, Lundberg et al found a low sensitivity of the Swedish Q16 in the screening of patients with a psycho-organic syndrome. 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.