Neurophysiological aspects of the completely locked-in syndrome in patients with advanced amyotrophic lateral sclerosis

Copyright © 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved..

OBJECTIVE: Amyotrophic lateral sclerosis (ALS) patients in completely locked-in syndrome (CLIS) are incapable of expressing themselves, and their state of consciousness and awareness is difficult to evaluate. Due to the complete paralysis included paralysis of eye muscles, any assessment of the perceptual and psychophysiological state can only be implemented in passive experimental paradigms with neurophysiological recordings.

METHODS: Four patients in CLIS were investigated in several experiments including resting state, visual stimulation (eyes open vs eyes closed), auditory stimulation (modified local-global paradigm), somatosensory stimulation (electrical stimulation of the median nerve), and during sleep.

RESULTS: All patients showed altered neurophysiological metrics, but a unique and common pattern could not be found between patients. However, slowing of the electroencephalography (EEG) and attenuation or absence of alpha wave activity was common in all patients. In two of the four patients, a slow dominant frequency emerged at 4 Hz with synchronized EEG at all channels. In the other two patients slowing of EEG appears less synchronized. EEGs between eyes open and eyes closed were significantly different in all patients. The dominant slow frequency during the day changes during slow-wave sleep (supposedly sleep stage 3) to even slower frequencies below 2 Hz. Somatosensory evoked potentials (SEPs) were absent or significantly altered in comparison to healthy subjects, similarly for auditory evoked potentials (AEPs).

CONCLUSIONS: The heterogeneity of the results underscores the fact that no single neurophysiological index is available to assess psychophysiological states in unresponsive ALS patients in CLIS. This caveat may also be valid for the assessment of cognitive processes; a functioning BCI can be the solution.

SIGNIFICANCE: Most of the studies of the neurophysiology of ALS patients focused on the early stage of the disease, and there are very few studies on the late stage when patients are completely paralyzed with no means of communication (i.e., CLIS). This study provides quantitative metrics of different neurophysiological aspects of these patients.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:132

Enthalten in:

Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology - 132(2021), 5 vom: 01. Mai, Seite 1064-1076

Sprache:

Englisch

Beteiligte Personen:

Khalili-Ardali, Majid [VerfasserIn]
Wu, Shizhe [VerfasserIn]
Tonin, Alessandro [VerfasserIn]
Birbaumer, Niels [VerfasserIn]
Chaudhary, Ujwal [VerfasserIn]

Links:

Volltext

Themen:

Amyotrophic lateral sclerosis
Auditory evoked potential
Completely locked-in syndrome
Journal Article
Research Support, Non-U.S. Gov't
Resting-state
Somatosensory evoked potential

Anmerkungen:

Date Completed 02.09.2021

Date Revised 02.09.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.clinph.2021.01.013

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM322997275