RT Journal Article
T1 Normalized Power Variance: A new Field Orthogonal to Power in EEG Analysis
A1 Aoki, Yasunori
A1 Bruña Fernández, Ricardo
A1 Ikeda, Manabu
AB To date, electroencephalogram (EEG) has been used in the diagnosis of epilepsy, dementia, and disturbance of consciousness via the inspection of EEG waves and identification of abnormal electrical discharges and slowing of basic waves. In addition, EEG power analysis combined with a source estimation method like exact-low-resolution-brain-electromagnetic-tomography (eLORETA), which calculates the power of cortical electrical activity from EEG data, has been widely used to investigate cortical electrical activity in neuropsychiatric diseases. However, the recently developed field of mathematics “information geometry” indicates that EEG has another dimension orthogonal to power dimension — that of normalized power variance (NPV). In addition, by introducing the idea of information geometry, a significantly faster convergent estimator of NPV was obtained. Research into this NPV coordinate has been limited thus far. In this study, we applied this NPV analysis of eLORETA to idiopathic normal pressure hydrocephalus (iNPH) patients prior to a cerebrospinal fluid (CSF) shunt operation, where traditional power analysis could not detect any difference associated with CSF shunt operation outcome. Our NPV analysis of eLORETA detected significantly higher NPV values at the high convexity area in the beta frequency band between 17 shunt responders and 19 non-responders. Considering our present and past research findings about NPV, we also discuss the advantage of this application of NPV representing a sensitive early warning signal of cortical impairment. Overall, our findings demonstrated that EEG has another dimension — that of NPV, which contains a lot of information about cortical electrical activity that can be useful in clinical practice.
PB SAGE Publications
SN 1550-0594
YR 2022
FD 2022-03-29
LK https://hdl.handle.net/20.500.14352/100411
UL https://hdl.handle.net/20.500.14352/100411
LA eng
NO Research Committee of Normal Pressure Hydrocephalus and Related Disorders
NO Japanese Ministry of Health, Labour and Welfare
NO Japan Agency for Medical Research and Development
NO Sugita Memorial Brain Research
DS Docta Complutense
RD 7 abr 2025