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

Galina V Portnova

doi:10.3389/fneur.2020.00122

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.

Highlights

The impact of chronic microvascular ischemia (CMI) on cognitive function has garnered significant research interest in recent years [1], the emotional impairment of patients with cerebral microvascular atrophy has not received a similar degree of attention
The Instrumental Activities of Daily Living (IADL) score positively correlated with difference of RATA between resting state and sounds of coughing and laughter (r = 0.495, p = 0.003) and sense of threat and suspiciousness (r = 0.521, p < 0.0007) for sounds of coughing, vomiting, barking, and laughter: the higher the RATA difference and sense of threat was, the higher IADL score the person had
Other studies have reported that patients with cerebrovascular dementia exhibit the lowest coherence between the different cortical areas [37], while reduced alpha-rhythm amplitude has been noted in patients with chronic ischemia [38]

Summary

Introduction

The impact of chronic microvascular ischemia (CMI) on cognitive function has garnered significant research interest in recent years [1], the emotional impairment of patients with cerebral microvascular atrophy has not received a similar degree of attention. The majority of data concerning emotional changes in patients with brain ischemia have been derived from post-stroke clinical cases. It is well-known that depression is a typical complication stemming from a left-hemisphere stroke [4], which is associated with both disability [5] and worse rehabilitation outcomes in stroke survivors [6]. The emotional disturbances experienced by chronic ischemia patients who do not exhibit localized brain damage have only rarely been investigated.

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