ABSTRACT
OBJECTIVE: Dichotic listening techniques have been used to study hemispheric dominance for language in schizophrenia. The authors' goal was to compare subjects with paranoid and undifferentiated subtypes of schizophrenia. METHOD: The Fused Rhymed Words Test was used to compare perceptual asymmetries in 16 patients with paranoid schizophrenia, 28 patients with undifferentiated schizophrenia, and 29 healthy comparison subjects. RESULTS: Patients with paranoid schizophrenia had the largest left hemisphere advantage and patients with undifferentiated schizophrenia had the smallest. The asymmetry of healthy subjects was intermediate. Hemisphere advantage varied as a function of gender only in the patients with undifferentiated schizophrenia. CONCLUSIONS: The findings support the hypotheses that undifferentiated schizophrenia is associated with underactivation of left hemisphere resources for verbal processing and that paranoid schizophrenia is characterized by preserved left hemisphere processing.
Subject(s)
Auditory Perception/physiology , Dichotic Listening Tests/statistics & numerical data , Dominance, Cerebral/physiology , Schizophrenia/diagnosis , Adult , Diagnosis, Differential , Female , Humans , Male , Psychiatric Status Rating Scales/statistics & numerical data , Schizophrenia/classification , Schizophrenia/physiopathology , Schizophrenia, Paranoid/diagnosis , Schizophrenia, Paranoid/physiopathology , Severity of Illness Index , Sex FactorsABSTRACT
BACKGROUND: Prior studies using simple target detection ("oddball") tasks with pure tones have reported asymmetric reduction of the P3 event-related potential (ERP). This study investigated the time course and topography of ERPs recorded during both tonal and phonetic oddball tasks. METHODS: Event-related potentials of 66 patients (14 unmedicated) diagnosed with schizophrenia (n = 46) or schizoaffective disorder (n = 20) and 32 healthy adults were recorded from 30 scalp electrodes during two oddball tasks using consonant-vowel syllables or complex tones. Overlapping ERP components were identified and measured by covariance-based principal components analysis. RESULTS: Schizophrenic patients showed marked, task-independent reductions of early negative potentials (N1, N2) but not reduced P3 amplitude or abnormal P3 asymmetry. Task-related hemispheric asymmetries of the N2/P3 complex were similar in healthy adults and schizophrenic patients. Poorer task performance in patients was related to ERP amplitudes, but could not account for reductions of early negativities. CONCLUSIONS: The findings suggest that both patients and control subjects activated lateralized cortical networks required for pitch (right frontotemporal) and phoneme (left parietotemporal) discrimination. Task-independent reductions of negativities between 80 and 280 msec after stimulus onset suggest a deficit of automatic stimulus classification in schizophrenia, which may be partly compensated by later effortful processing.
Subject(s)
Brain/physiopathology , Evoked Potentials/physiology , Schizophrenia/physiopathology , Speech Perception/physiology , Adult , Antipsychotic Agents/therapeutic use , Female , Frontal Lobe/physiopathology , Functional Laterality/physiology , Humans , Male , Parietal Lobe/physiopathology , Phonetics , Schizophrenia/drug therapy , Speech Discrimination Tests , Temporal Lobe/physiopathologyABSTRACT
In spite of what first seemed like insurmountable hurdles, two competing Denver hospitals have joined together in an innovative plan to provide magnetic resonance imaging (MRI) services. Their alliance may be a model for other hospitals in the same type of competitive environment.
