OĞUZ TAN, SERAP AYDIN, Gökben HIZLI SAYAR, Doğa GÜRSOY

EEG complexity and frequency in chronic residual schizophrenia

Amaç: Şizofreni üzerine yapılan çalışmaların bir kısmı elektroensefalografide (EEG) kompleksitenin arttığını, bazı çalışmalar ise azaldığını göstermiştir. Bu çelişki hastalığın klinik özelliklerine veya kullanılan ölçüm yöntemlerine bağlı olabilir. Bunu giderebilmek için biz hastalık süresi ve belirti profili açısından benzer bir şizofreni hasta grubunu seçtik (kronik rezidüel şizofrenisi olanlar) ve iki farklı kompleksite ölçüm yöntemi uyguladık. Yöntem: Sağ elli kronik rezidüel şizofreni hastaları (10 erkek, 10 kadın) ve yaş ve cinsiyet aşısından eşleştirilmiş 20 sağlıklı kontrol çalışmaya alındı. Gözler kapalıyken yapılan çekime dayanarak her elektrot bölgesi için nicel EEG band aktiviteleri, log enerji entropi (LEE) ve Hurst eksponentleri (HE) ölçüldü. Sonuçlar: Prefrontal, frontal, temporal and pariyetal alanlarda LEE değerleri şizofreni hastalarında kontrollerle karşılaştırıldığında anlamlı derecede yüksekti. Şizofreni hastalarında sağ frontal alanda anlamlı derecede yüksek HE değerleri saptandı. Hasta grubunda prefrontal, frontal ve pariyetal delta aktivitesi; prefrontal, sol temporal ve sağ pariyetal teta aktivitesi ve sol temporal alfa aktivitesi yüksekti. Tartışma: Bu çalışmada, kronik rezidüel şizofrenide EEG'nin daha az kompleks ve daha 'düz' olduğunu bulduk. Hastaların EEG'lerinde, baskın olarak prefrontal ve frontotemporal alanlarda yavaşlama gözlemledik. EEG kompleksite ve frekans analizlerinin birlikte kullanımı şizofreni araştırmalarında yeni bir araç olabilir.

Kronik rezidüel şizofrenide EEG kompleksitesi ve frekansı

Objective: Some studies on schizophrenia showed an increased complexity in electroencephalography (EEG) whereas others detected a decreased complexity. Because this discrepancy might be due to the clinical features or complexity measures used, we employed two different complexity measures in a group of schizophrenics similar in illness duration (chronic) and symptom profile (residual). Methods: Right-handed chronic residual schizophrenic patients (10 male, 10 female) and age- and sex-matched 20 healthy controls were included in the study. Eyesclosed resting EEG series were measured through quantitative EEG band activities, the log energy entropy (LEE) values, and the Hurst exponents (HE) of EEG measurements were computed for each electrode site. Results: Significantly higher LEE values in the prefrontal, frontal, temporal and parietal locations were observed in schizophrenic patients compared with controls. HE values were significantly higher on the right frontal area in the schizophrenics. Patient group showed increased prefrontal, frontal and parietal delta activity, prefrontal, left temporal and right parietal theta activity and increased left temporal alpha activity. Discussion: In the present study, we found that chronic residual schizophrenia is associated with decreased complexity and increased smoothness in EEG. In addition, EEG of patients was characterized by obvious slowness at prefrontal and frontotemporal regions, dominantly. An integration of EEG complexity and frequency analysis can be proposed as an innovative tool in schizophrenia research.

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