Table 6:
Electrophysiological biomarkers in schizophrenia.
| Biomarkers | Tools | Participants | Conclusion | Diagnostic aspects | References |
|---|---|---|---|---|---|
| EPRs | EEG | ||||
| P3 (P3a and P3b) | Systematic review: 133 studies | Multiple EEG-indices were altered during at-risk mental state and early stages of schizophrenia | Diagnostic biomarkers: identify the risk of schizophrenia to benefit early diagnosis and intervention | [250] | |
| P50 | |||||
| MMN | 33 cases and 42 controls | Schizophrenia patients exhibited reduced MMN activity at frontocentral electrode sites | Diagnostic biomarkers: evaluate disease severity and progression | [220] | |
| LPP | 339 cases and 331 controls | Patients have slightly diminished P3 and LPP amplitudes in response to positive and negative stimuli | Diagnostic biomarkers: evaluate disease severity and progression | [223] | |
| Gamma range | 58 cases and 48 controls | the lack of age-related changes in deletion carriers indexes a potential developmental impairment in circuits underlying the maturation of neural oscillations during adolescence | Diagnostic biomarkers: identify the risk of schizophrenia | [251] | |
| Eye movement | Eye tracker | 1911 subjects | the antisaccade error rate as a putative schizophrenia spectrum marker. | Diagnostic biomarkers: identify the risk of schizophrenia | [252] |
| Retinal function | ERG and OCT | 2079 cases and 1571 controls | Retinal abnormalities may be applicable as state/trait markers in schizophrenia spectrum disorders | Diagnostic biomarkers: identify the risk of schizophrenia | [235] |
| a-waves and b-waves | |||||
| Retinal nerve fiber layer | |||||
| Macular ganglion cell layer | |||||
| Optic cup volume | |||||
| Heart rate variability | ECG | Systematic review: 34 studies | Given the association between low HRV, threat processing, emotion regulation and executive functioning, reduced vagal tone may be an endophenotype for the development of psychotic symptoms. | Diagnostic biomarkers: identify the risk of schizophrenia | [239] |
| HF | |||||
| LF |
EEG, electroencephalogram; ERPs, event-related potentials; MMN, mismatch negativity; LPP, late positive potential; ERG, electroretinogram; OCT, Optical coherence tomography; EEG, electrocardiogram; HF, high frequency; LF, low frequency.