delta waves – American ME and CFS Society

Electroencephalographic Abnormalities in a Patient Suffering from Long-Term Neuropsychological Complications following SARS-CoV-2 Infection

Abstract:

Introduction: Emotional apathy has recently been identified as a common symptom of long COVID. While recent meta-analyses have demonstrated generalized EEG slowing with the emergence of delta rhythms in patients hospitalized for severe SARS-CoV-2 infection, no EEG study or dopamine transporter scintigraphy (DaTSCAN) has been performed in patients with long COVID presenting with apathy. The objective of this case report was to explore the pathophysiology of neuropsychological symptoms in long COVID.

Case presentation: A 47-year-old patient who developed a long COVID with prominent apathy following an initially clinically mild SARS-CoV-2 infection underwent neuropsychological assessment, cerebral MRI, DaTSCAN, and resting-state high-density EEG 7 months after SARS-CoV-2 infection. The EEG data were compared to those of 21 healthy participants. The patient presented with apathy, cognitive difficulties with dysexecutive syndrome, moderate attentional and verbal episodic memory disturbances, and resolution of premorbid mild gaming disorder, mild mood disturbances, and sleep disturbances. His MRI and DaTSCAN were unremarkable. EEG revealed a complex pattern of oscillatory abnormalities compared to the control group, with a strong increase in whole-scalp delta and beta band activity, as well as a decrease in alpha band activity. Overall, these effects were more prominent in the frontal-central-temporal region.

Conclusion: These results suggest widespread changes in EEG oscillatory patterns in a patient with long COVID characterized by neuropsychological complications with prominent apathy. Despite the inherent limitations of a case report, these results suggest dysfunction in the cortical networks involved in motivation and emotion.

Source: Benis D, Voruz P, Chiuve SC, Garibotto V, Assal F, Krack P, Péron J, Fleury V. Electroencephalographic Abnormalities in a Patient Suffering from Long-Term Neuropsychological Complications following SARS-CoV-2 Infection. Case Rep Neurol. 2023 Dec 5;16(1):6-17. doi: 10.1159/000535241. PMID: 38179211; PMCID: PMC10764086. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10764086/ (Full text)

A systematic review of quantitative EEG findings in Long COVID, Fibromyalgia and Chronic Fatigue Syndrome

Abstract:

Long COVID (LC) is a multisymptom clinical syndrome with similarities to Fibromyalgia Syndrome (FMS) and Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME). All these conditions are believed to be associated with centrally driven mechanisms such as central sensitisation.

There is a lack of consensus on quantitative EEG (qEEG) changes observed in these conditions. This review aims to synthesise and appraise the literature on resting-state qEEG in LC, FMS and CFS/ME, to help uncover possible mechanisms of central sensitisation in these similar clinical syndromes.

A systematic search of MEDLINE, Embase, CINHAL, PsycINFO and Web of Science databases for articles published between December 1994 and September 2023 was performed. Following screening for predetermined selection criteria and out of the initial 2510 studies identified, 17 articles were retrieved that met all the inclusion criteria, particularly of assessing qEEG changes in one of the three conditions compared to healthy controls. All studies scored moderate to high quality on the Newcastle-Ottawa scale.

There was a general trend for decreased low frequency EEG band activity (delta, theta, and alpha) and increased high-frequency EEG beta activity in FMS, whereas an opposite trend was found in CFS/ME. The limited LC studies included in this review focused mainly on cognitive impairments and showed mixed findings not consistent with patterns seen in FMS and CFS/ME.

Further research is required to explore whether there are phenotypes within LC that have EEG signatures similar to FMS or CFS/ME. This could inform identification of reliable diagnostic markers and possible targets for neuromodulation therapies.

Source: Bárbara Silva-Passadouro, Arnas Tamasauskas, Omar Khoja, Alexander J. Casson, Ioannis Delis, Christopher Brown, Manoj Sivan. A systematic review of quantitative EEG findings in Long COVID, Fibromyalgia and Chronic Fatigue Syndrome. medRxiv [Preprint] https://www.medrxiv.org/content/10.1101/2023.11.06.23298171v1.full-text (Full text)

Electroencephalogram characteristics in patients with chronic fatigue syndrome

Abstract:

OBJECTIVE: To explore the electroencephalogram (EEG) characteristics in patients with chronic fatigue syndrome (CFS) using brain electrical activity mapping (BEAM) and EEG nonlinear dynamical analysis.

METHODS: Forty-seven outpatients were selected over a 3-month period and divided into an observation group (24 outpatients) and a control group (23 outpatients) by using the non-probability sampling method. All the patients were given a routine EEG. The BEAM and the correlation dimension changes were analyzed to characterize the EEG features.

RESULTS: 1) BEAM results indicated that the energy values of δ, θ, and α1 waves significantly increased in the observation group, compared with the control group (P<0.05, P<0.01, respectively), which suggests that the brain electrical activities in CFS patients were significantly reduced and stayed in an inhibitory state; 2) the increase of δ, θ, and α1 energy values in the right frontal and left occipital regions was more significant than other encephalic regions in CFS patients, indicating the region-specific encephalic distribution; 3) the correlation dimension in the observation group was significantly lower than the control group, suggesting decreased EEG complexity in CFS patients.

CONCLUSION: The spontaneous brain electrical activities in CFS patients were significantly reduced. The abnormal changes in the cerebral functions were localized at the right frontal and left occipital regions in CFS patients.

Source: Wu T, Qi X, Su Y, Teng J, Xu X. Electroencephalogram characteristics in patients with chronic fatigue syndrome. Neuropsychiatr Dis Treat. 2016 Jan 28;12:241-9. doi: 10.2147/NDT.S92911. ECollection 2016. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734796/ (Full article)

Behavioral perturbation and sleep in healthy and virus-infected inbred mice

Abstract:

Murine gammaherpesvirus (MuGHV) is a natural pathogen of wild rodents that has been studied extensively in terms of host immune responses to herpesviruses during acute infection, latency, and reactivation from latency. Although herpesvirus infections in people can be associated with fatigue and excessive sleepiness during both acute and latent infection, MuGHV has not been assessed extensively as a model for studying the behavioral consequences of chronic latent herpesvirus infections.

To assess MuGHV infection as a model for evaluating fatigue and assessing potential mechanisms that underlie the exacerbation of fatigue during chronic viral disease, we evaluated sleep, temperature, and activity after exposure of healthy and latently MuGHV-infected mice to sleep fragmentation and social interaction. Neither treatment nor infection significantly affected temperature. However, at some time points, latently infected mice that underwent sleep fragmentation had less locomotor activity and more slow-wave sleep than did mice exposed to social interaction. In addition, delta-wave amplitude during slow-wave sleep was lower in infected mice exposed to sleep fragmentation compared with uninfected mice exposed to the same treatment.

Both reduced locomotor activity and increased time asleep could indicate fatigue in infected mice after sleep fragmentation; reduced delta-wave amplitude during slow-wave sleep indicates a light plane of sleep from which subjects would be aroused easily. Identifying the mechanisms that underlie sleep responses of mice with chronic latent MuGHV infection may increase our understanding of fatigue during infections and eventually contribute to improving the quality of life for people with chronic viral infections.

Source: Trammell RA, Toth LA. Behavioral perturbation and sleep in healthy and virus-infected inbred mice. Comp Med. 2014 Aug;64(4):283-92. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4170093/ (Full article)

Ultra-slow delta power in chronic fatigue syndrome

Abstract:

The role of sleep in patients diagnosed with chronic fatigue syndrome is not fully understood. Studies of polysomnographic and quantitative sleep electroencephalographic (EEG) measures have provided contradictory results, with few consistent findings in patients with Chronic Fatigue Syndrome (CFS). For the most part, it appears that delta EEG activity may provide the best discrimination between patients and healthy controls. A closer examination of delta activity in the very slow end of the frequency band is still to be considered in assessing sleep in CFS.

The present preliminary study compared absolute and relative spectral power in conventional EEG bands and ultra-slow delta (0.5-0.8Hz) between 10 young female patients with the CFS and healthy controls without psychopathology. In absolute measures, the ultra-slow delta power was lower in CFS, about one-fifth that of the control group. Other frequency bands did not differ between groups. Relative ultra-slow delta power was lower in patients than in controls.

CFS is associated with lower ultra-slow (0.5-0.8Hz) delta power, underscoring the importance of looking beyond conventional EEG frequency bands. From a neurophysiological standpoint, lower ultra-slow wave power may indicate abnormalities in the oscillations in membrane potential or a failure in neural recruitment in those with CFS.

Source: Le Bon O, Neu D, Berquin Y, Lanquart JP, Hoffmann R, Mairesse O, Armitage R. Ultra-slow delta power in chronic fatigue syndrome. Psychiatry Res. 2012 Dec 30;200(2-3):742-7. doi: 10.1016/j.psychres.2012.06.027. Epub 2012 Jul 6. https://www.ncbi.nlm.nih.gov/pubmed/22771174