In Norway there is agreement on the principal criteria for diagnosing occupational solvent exposure related disease. However, diagnostic practice is not based on a common diagnostic model. In cooperation with Norwegian institutions diagnosing occupational disease, the Norwegian Knowledge Centre for the Health Services has performed a search for clinical studies reporting effects on longterm occupational solvent exposure. We have sorted the identified studies according to study design, population, type of health examination, and study question. We did not summarize the results nor evaluate the quailty of the studies.

• We identified seven systematic reviews published after 2000, and 253 primary studies published between 1980 and May 2008. We found that 67% of the studies were small with less than 100 exposed participants, the majority of these reported results from a non exposed control group, but there were no RCTs.
• We found that 198 studies reported on exposed workers with no a priori known diseases, 22 reported on patients with symptoms, and 33 reported on patients diagnosed with chronic toxic encephalopathy (CTE) and/or toxic poly neuropathy (TPN).
• We found that 150 of the publications reported on outcomes of neuro-psychological examinations alone, or in combination with neurological, neuro-physiological and/or neuro-pathological health examinations. 103 publications reported only on outcomes different from neuro-psychological.
• We found that 47 publications reported on diagnostic test performance, and 40 on prognosis.
• With exception of one study, we found no publications that reported on diagnostic accuracy of a particular test or procedure.

The chosen study designs, population sizes, and/or study questions provide uncertain answers to questions related to choice and outcomes of diagnostic tests. Nevertheless, selected studies may constitute a part of the evidence for choice of diagnostic procedures.