Lack of a Sense of Threat and Higher Emotional Lability in Patients With Chronic Microvascular Ischemia as Measured by Non-linear EEG Parameters

Abstract

We aimed to investigate the non-linear features of the electroencephalogram (EEG) findings in patients with chronic microvascular ischemia (CMI) in order to determine the brain correlates of emotional impairment that could impact the risk of developing acute ischemia. We compared the EEG responses of patients with CMI and age-matched healthy volunteers to non-verbal emotionally charged sounds. We analyzed the EEG data, the psychological assessment of the stimuli, and the results of neuropsychological and behavioral testing. We assessed the (in)stability of the envelope's amplitude by calculating its average frequency and the ratio of its standard deviation to its mean. The non-linear features were lower in the patient group in the resting state. The emotional stimulation induced a decrease in the frequency of the envelope's amplitude in all subjects. Changes in the fractal dimension during stimulation were only seen in the patient group, and they correlated with symptoms of emotional lability. The lower ratio of the alpha-rhythm envelope's standard deviation to its mean in the right hemisphere correlated with a higher sense of threat. The EEG and behavioral correlates of emotional impairment in patients with CMI were found.

Acoustic and Subjective Basis of Emotional Perception in Comatose Patients: A Comparative Study

“…Finally, as we mentioned, we found significant changes in some nonlinear EEG parameters associated with emotional perception [ 5 , 28 ] both in healthy individuals and patients with mental or neurological diseases. In particular, previous studies demonstrated that higher HFD was associated with different emotional states, including affect, fear, happiness, sadness, and empathy [ 5 , 26 , 28 , 63 , 64 ].…”

“…Considering the previous findings [ 5 , 28 ], we applied nonlinear EEG analysis to assess the emotional response to the presented sounds. We used a Butterworth filter of 12 order to calculate the examined signal bandpass filtered in the range of interest (1.6−30 Hz).…”

“…These features could also have an excellent prognostic value regarding comatose patients [ 25 ]. In addition, the fractal dimension was previously associated with the perception of emotional stimuli; an increase in these EEG parameters was previously associated with emotional arousal, empathy, fear, and other emotional states and could be revealed in patients with a mental disability or brain damage [ 5 , 26 - 28 ]. The HC was also associated with emotional states such as irritation, happiness, or scariness [ 29 ].…”

Atypical EEG Responses to Nonverbal Emotionally Charged Stimuli in Children with ASD

“…At the same time, the emotional sounds of crying and laughter induced a decrease in FD in children with ASD compared to other conditions; as a result, the values of FD became similar to the rates of the control group. As was shown previously, the FD of EEG was associated with the BOLD signal of the limbic system [ 38 ] and could be used to assess the emotional tone of presented stimuli as well as the variable emotional states of participants [ 39 , 40 ] such as arousal [ 41 ] or an emotional stress state [ 42 ]. The decrease in FD in children with ASD could be associated with emotional responses to laughter and crying and also could be explained by higher attention to these stimuli.…”

Residual and compensatory changes of resting‐state EEG in successful recovery after moderate TBI

“…In the previous studies, we showed that Hjorth complexity, envelope frequency, and ratio were sensitive to emotionally charging stimuli in patients with various neurological or mental disorders [12]. Further, we proposed that these non‐linear patterns of EEG could assess possible trauma‐induced mood changes in patients [13]. In this study, we also hypothesized that altered non‐linear patterns of resting‐state EEG could indicate both the chronic mood changes and cognitive deficits in patients previously suffering moderate TBI.…”