DISORDERS OF EARLY INFORMATION-PROCESSING AND VIGILANCE AS VULNERABILITY MARKERS OF SCHIZOPHRENIA

Disordered processes of scanning iconic memory and vigilance deficits are well-known phenomena in schizophrenics. The ''Span of Apprehension '' and the ''Continuous Performance Test'' are among the most importan t research techniques assessing these Impairments and are considered p ossible neuropsychological vulnerability markers of schizophrenia. Num erous studies compared schizophrenics with psychiatric control groups on these tasks to determine the specificity of the performance deficit s which represents a central criterion for vulnerability markers. The review of the empirical results suggests a non-specificity of the perf ormance of schizophrenics on the ''Span of Apprehension'' and the degr aded stimulus version of the Continuous Performance Test. These findin gs are critically discussed with reference to the technical and method ological characteristics of the studies. Furthermore, studies are pres ented which examined the relationship of vigilance performance on the Continuous Performance Test and rate of detecting on ''Span of Apprehe nsion'' and psychopathological symptoms with the aim to evaluate the m arker qualities of these research techniques for schizophrenic symptom s. According to the available data a partial symptomatic specificity c an be attributed to the ''Span of Apprehension''.