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Reaction‐times and bioelectrical brain signals of drug‐naive schizophrenic first‐onset patients in identification and classification tasks
Author(s) -
Krieger S.,
Lis S.,
Gallhofer B.
Publication year - 2001
Publication title -
acta psychiatrica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.849
H-Index - 146
eISSN - 1600-0447
pISSN - 0001-690X
DOI - 10.1034/j.1600-0447.2001.104s408042.x
Subject(s) - psychology , audiology , lateralization of brain function , cognition , electroencephalography , identification (biology) , perception , schizophrenia (object oriented programming) , selection (genetic algorithm) , neuroscience , cognitive psychology , psychiatry , artificial intelligence , medicine , computer science , botany , biology
Objective: The question of the present study is whether disturbances of response‐selection in schizophrenic patients are discernible only if overt motor‐actions are required, or also if covert cognitive actions are necessary. Method: Visual identification (digits) and classification (dot‐enumeration) tasks were presented to 18 drug‐naive, first‐onset schizophrenic patients and healthy controls. It is assumed that enumeration of more than three dots requires additional cognitive processes as buffering and re‐focusing of attention. Reaction‐times and 21‐channel‐EEG were measured. For eye‐movement artefact‐elimination a new non‐parametric regression approach was applied. Results: Reaction‐times revealed that in the patient group response selection is lengthened in both tasks. Perception of dot numbers is not affected. Bioelectrical data depicted a left‐lateralization of posterior P100 and N100 in the patient group as well as an enhanced fronto‐central P200. Conclusion: Whereas in reaction‐times of patients only a disturbance of response selection is discernible, bioelectrical measurements also point to an altered organization of perceptive processes.