조헌병의 EEG pattern

People with schizophrenia and their healthy siblings share patterns of brain activity that are different from those seen in individuals with no family history of the disorder, scientists from EPFL have found. Because the siblings do not show schizophrenia symptoms, this brain 'signature' could serve as a marker for the early diagnosis of the disorder. The findings, published in Nature Communications, could open up avenues for developing new treatments for schizophrenia.

Schizophrenia appears in adolescence or adulthood and often comes with false beliefs, paranoid thoughts, and a tendency to see or hear things that aren't there. The strongest risk factor for the disorder is the presence of an affected close relative: one in ten siblings of people with schizophrenia are predicted to develop the disorder, compared with one in 100 individuals among the general population.

However, scientists have known that there is no one single genetic variant that causes schizophrenia. The disorder rather stems from many different DNA mutations, duplications, and deletions that cause the developing brain to go awry. For this reason, predicting who's at risk of developing schizophrenia is no simple task.

the team scanned the participants' brains using resting-state electroencephalography (EEG). This non-invasive technique measures the brain's electrical activity via electrodes attached to the scalp of individuals as they relax and sit still for about five minutes.

Previous work has revealed that individuals with schizophrenia have abnormal EEG microstates, but the new study is the first to show that unaffected siblings share the same abnormalities in these brain patterns.

The researchers found that a specific type of microstate, called class C, occurred more frequently and for longer durations in individuals with schizophrenia and their siblings than it did in healthy people. Other brain activity patterns, known as microstate class D, occurred less frequently and for shorter amounts of time in those with schizophrenia and their siblings than in healthy individuals.

What's more, people who had just experienced their first episode of psychosis showed the same anomalous patterns of brain activity as those who had been suffering from schizophrenia for years. "This suggests that these microstate abnormalities occur right at the beginning of the disease,"

The team also found that a third type of microstate, called class B, occurred more frequently and for longer periods in siblings than in individuals with schizophrenia. This might explain why healthy siblings do not show schizophrenia-related behaviors, despite sharing the same brain 'signature' as people with the disorder. 

How the alterations in EEG microstates affect brain function is still unclear, Herzog cautions. "But for diagnostic purposes, you don't need to know that," he adds. 

 

어떻게 pattern을 뽑아내었을까? noise도 많고, 비슷한 파형이여도 interval이 다르던가 할텐데, 어떤 신호처리를 했을까싶다.

 

 

reference

Janir Ramos da Cruz et al. EEG microstates are a candidate endophenotype for schizophrenia, Nature Communications (2020). DOI: 10.1038/s41467-020-16914-1