EEG Features in Adolescent Females with Self-Injurious Behavior in Endogenous Depressions

Background: the study of clinical and neurophysiological aspects of non-suicidal self-injurious behavior (NSSI), as one of the forms and risk factors for suicidal behavior in adolescents, including those suffering from mental disorders, is an urgent medical and social scientific task. Objective: To identify the features of EEG in depressive adolescent females with NSSI compared with EEG of age norm. Patients and methods: the study included 60 female patients aged 16–25 years with NSSI in the structure of endogenous depressive conditions, and 20 healthy subjects of the same gender and age. Clinical, psychopathological, psychometric, neurophysiological and statistical methods were used. Topographic EEG mapping revealed differences in the background EEG quantitative parameters of two studied groups. Results and discussion: spectral power values of alpha-2 (9–11 Hz) and alpha-1 (8–9 Hz) EEG frequency components in occipital-parietal and temporal leads, of theta-2 activity (6–8 Hz) in central-parietal leads, as well as of delta activity (2–4 Hz) in frontal and anterior temporal leads were higher in the left hemisphere, reflected increased activation of the right hemisphere. Generalized bilaterally synchronous alpha-theta bursts were registered regularly in EEG of NSSI patients, as well. Conclusions: the spatial distribution of EEG frequency components in depressive patients with NSSI indicates relatively decreased functional state of the cortex, especially of the left hemisphere and of its anterior regions, responsible for voluntary control of activity, with higher level of activation of temporal regions of the right hemisphere, associated with formation of negative emotions, and increased excitability of brain limbic-diencephalic structures, that may underlie poor controlled impulsive behavior.

Coherence of EEG Frequency Components While Performing Alternative Finger Movements in Women with Different Modal Frequency of Alpha-rhythm

A test group consisting of 113 right-hand healthy women from the ages of 19 to 21 was divided into two groups according to the average magnitude of their individual modal α- frequency – groups with high and low values of individual modal α- frequency. The ideal time of a simple sensorimotor reaction and choice-point behavior as well as speed capabilities of nervous processes during the tapping test, and measures of the coherence of EEG frequency components individually determined for each testee in quiescent intervals and while performing alternative movements by the right hand fingers were evaluated. Women with high modal α-frequency had better speed capabilities of nervous processes. Women with a high IαF had a less time of simple and complex reactions. The increase of coherence coefficients was seen throughout the EEG frequency spectrum in women performing alternate movements by fingers. Alternate movements of fingers performed by women with low α-frequency are provided by even higher frequency coherence of the EEG components in frontal, anterior temporal and central areas and by much lower frequency in the posterior temporal and parietal-occipital cortex areas compared to testees with high α-frequency.

Coherence of EEG frequency components during manual movements executed by the subdominant hand in women

The academic community is paying more and more attention to the question of the individual characteristics of the brain processes which ensure the manual motor programming of movements performed not only by the leading, but also by the subdominant hand. Researchers do not exclude the existence of the particular parameters of the human brain correlating with manual motor activities. This study involved 136 women at the age of 19–21 years. The testees were divided into two groups according to high and low values of the EEG modal α-frequency determined individually and in a motionless state. We evaluated the coherence status of the EEG frequency components in the motionless state and during movements performed by fingers of the subdominant (left) hand in response to rhythmic sound signals. The testing stages involved the sequential execution of motor tasks including clamping and unclamping performed by the fingers of the subdominant hand (such as grasping movements) without effort. The testees also performed fingering (a manual response to each stimulus) at in different times and not by all the fingers of the hand simultaneously, but separately, one by one, in a given sequence). Clamping and unclamping was executed by the fingers subject to power loading the (additional load on the fingers being 10H). Execution of manual movements by means of the subdominant hand in response to the sensory signals was accompanied by an increase in coherence in the EEG frequency components, especially in the frontal, temporal, and parietal cortexes of the central areas. Women with a low individual α-rate of such a regularity had significantly increased scores at the high (α3-, β-) frequencies of the EEG spectrum. At the same time, women in both groups mainly showed a decrease in the coherence coefficients of θ-, α1- and α3-activity in the frontal cortex leads in terms of the execution of the sequential finger movements and movements under power loading. The analysis of differences proved that women with a low IαF had relatively higher coherence of the EEG frequency components in the frontal lobes. However, relatively higher frequency components of EEG coherence in the central, posterior temporal and parietal leads were set in women with high IαF. Changes in cortical activity were established during different movements performed by fingers of the subdominant hand, namely, grasping movements of common occurrence, successive movements and movements under power loading. They differ from each other in their low specificity. Thus, the factor of motor performance of tests by means of the subdominant hand had obviously more decisive importance in the nature of the organization of brain activity than for the actual specifics of manual movements.