Quantitative characteristics of the alpha-rhythm of the electroencephalogram in depressive disorders

Abstract

The aim of research was to study the quantitative characteristics of the alpha rhythm in patients with depressive disorders.
 Material and methods. The study sample consisted of patients who were treated at the clinic of the Research Institute of Mental Health (department of affective states) Tomsk NIMC. A total of 84 patients (67 women, 17 men) aged 20 to 60 years with mood disorders in the framework of a depressive episode, recurrent depressive disorder and dysthymia were examined. An electroencephalogram was recorded at rest with closed and open eyes. The values of the absolute spectral power of the alpha rhythm, the parameters of the microstructure of the alpha spindle were analyzed and the reactivity index (the Berger effect) was calculated.
 Results. With open eyes, the spectral power of the alpha rhythm was statistically significantly higher in patients with depressive disorders in the Fp1 (p=0.041), F4 (p=0.042), F7 (p=0.046) and T4 (p=0.047) leads compared to the control. Also, in patients with depressive disorders, a predominantly low-amplitude alpha rhythm was recorded (53.6% vs. 26.7%, p=0.006). The degree of alpha-rhythm depression in the posterior temporal leads T5 (p=0.012) and T6 (p=0.006) was statistically significantly less pronounced in patients with depressive disorders compared to the control group of healthy individuals.
 Conclusion. The detected changes indirectly indicate a decrease in the oscillatory activity of brain processes in depressive disorders.