Influence of personality traits on neuropsychological test performance in toxic encephalopathy cases and healthy referent subjects.
The relationship between personality traits and cognitive performance was studied in two groups: men with symptoms and neuropsychological test results compatible with toxic encephalopathy (TE) and demographically similar healthy men (N=57 per group). Personality traits were assessed with the Karolinska Scales of Personality (KSP). The neuropsychological examination included 13 tests covering various functional domains. The TE group displayed elevated scores on all three KSP anxiety scales as well as an elevated impulsiveness score. Furthermore, the TE group had a lower score on the socialization scale than did the referent group. Different relationships between personality dispositions and cognitive functioning emerged in the two groups. Within the referent group the highest correlations were observed between KSP anxiety and socialization scale scores and reaction times measures. This pattern did not appear in the TE group; instead, divergent and a few weak relationships emerged. These relationships involved correlations between the KSP monotony avoidance score and some motor speed scores. By dividing the referent group into low anxiety and high anxiety subgroups on the basis of the multi-component anxiety scale score, it was shown that the test scores in the high anxiety subgroup mostly were indistinguishable from the scores in the TE group. In contrast, the low anxiety group had higher test scores than the TE group in 8 of the 13 tests. In conclusion, the expected relationship between anxiety and cognitive vigilance is absent in TE cases. This indicates that the neuropsychological performance decrement in TE cases is not primarily related to elevated mental distress, but is probably dominated by the effects of organic brain impairment. Thus, in TE cases low neuropsychological test scores should not be regarded as a consequence of emotional symptoms. Furthermore, personality traits may be considered as potential confounders even if traditional matching by demographic criteria has been successfully implemented.
Persson
R
R
Department of Psychology, Lund University, Sweden. Roger.Persson@ymed.lu.se
Osterberg
K
K
Karlson
B
B
Orbaek
P
P
D001007:Anxiety; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D020258:Neurotoxicity Syndromes / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology*; D016273:Occupational Exposure; D010551:Personality; D010555:Personality Inventory; D012016:Reference Values; D012919:Social Behavior; D013315:Stress, Psychological; D011795:Surveys and Questionnaires