A shared low-frequency oscillatory rhythm abnormality in resting and sensory gating in schizophrenia.

OBJECTIVES

We hypothesized that an oscillatory abnormality that is consistently observed across various testing paradigms may index an elementary neuronal abnormality marking schizophrenia risk.

METHODS

Compared neural oscillations in resting EEG and sensory gating conditions in schizophrenia patients (n=128), their first-degree relatives (n=80), and controls (n=110) and calculated phenotypic and/or genetic correlation of the abnormal measure across these conditions.

RESULTS

Using a uniform, single trial analytical approach, we identified two prominent oscillatory characteristics in schizophrenia: (1) augmented neural oscillatory power was pervasive in medicated schizophrenia patients in most frequencies, most prominent in the theta-alpha range (4-11 Hz) across the two paradigms (all p<0.007); and (2) their first-degree relatives shared significantly augmented oscillatory energy in theta-alpha frequency in resting (p=0.002) and insufficient suppression of theta-alpha in sensory gating (p=0.01) compared with normal controls. Heritability estimates for theta-alpha related measures for resting and gating conditions ranged from 0.44 to 0.49 (p<0.03). The theta-alpha measures were correlated genetically with each other (RhoG=0.82±0.43; p<0.05).

CONCLUSIONS

Augmented theta-alpha rhythm may be an elementary neurophysiological problem associated with genetic liability of schizophrenia.

SIGNIFICANCE

This finding helps to refine key electrophysiologic biomarkers for genetic and clinical studies of schizophrenia.