Neuropsychological test performance of Swedish multiple chemical sensitivity patients--an exploratory study

To address the hypothesis of brain dysfunction as a component of the multiple chemical sensitivity (MCS) syndrome, a neuropsychological battery comprising 8 tests was given to 17 Swedish MCS patients and 34 demographically matched controls. Across the 6 tests used as indicators of brain impairment, comprising a total of 17 test variables, the MCS group performed poorer only in a complex reaction time test (mean reaction time; p = 0.002; t test). Correction for self-ratings of mental distress and trait psychasthenia did not eliminate the deviation in the reaction time test. Because the results on most tests were within normal limits, brain impairment was not evidenced. However, the similar minor deviations in neurobehavioral tests observed in several studies of MCS patients indicate the need for a study on a larger sample of MCS cases.