Frontal cortex reactivity differentiates between schizophrenic subtypes: auditory ERP-evidence.

Objectives: To extend the hypothesis that late auditory EP shifts represent pathophysiologcial markers in schizophrenia.

Methods: Early negative (±100 μs) and late positive (>300 ms) auditory oddball and CNV responses are topographically compared in 3 medicated schizophrenic subtypes.

Results: Only late cortical responses differentiate between paranoid, residual and disorganised schizophrenia.

Impaired early visual processing in disorganised schizophrenia.

Topographic differences in flash/pattern shift VEP data are evaluated in paranoid (n: 38), disorganized (n: 23) and residual (n: 23) schizophrenic subtypes and compared to normal controls. Increased early P1 and a restricted diffusion of the late P2 responses suggest dopaminergic over- and cholinergic underactivity in paranoid and residual schizophrenia. A distinctive pattern N145 reflects well-preserved attentional resources in the paranoid subtype.

Facilitation of early and masking of late cortical responses in dementia.

Topographic differences in longlatency SSEP and flash VEP data are compared in 3 different psychiatric patient groups. Differences between schizophrenia and affective disorder are restricted to somatosensory P100 amplitude gradients along the antero-posterior axis. In contrast EP-differences between psychiatric patients and dementia are prominent, encompassing both late and early (< 100 ms) responses.

Auditory information processing in schizophrenia.

Early N1P2 and late N2P3 responses generated in an auditory oddball paradigm are topographically compared in three psychiatric patient groups. In schizophrenia N1 and N2 amplitude is comparable with dementia and significantly decreased with respect to affective disorder. In contrast, P3 amplitude does not allow discriminating schizophrenia from affective disorder but is significantly diminished in dementia.