From: Electroencephalography in delirium assessment: a scoping review
Authors | Journal | Design | N Total (Delirium/No Delirium) | Mean Age | % Female | Admission | Dementia | Substance (Ab)use | Delirium Tool | EEG Type | Ana-lysis Meth-od | EEG Set-up | Summary Findings |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Allahyari et al. (1976) [42] | Psychiatr Clin | Prospective | 30 (30/0) | N.m. | 0 | Intoxication/ Withdrawal | N.m. | Substance abuse reported and considered in analysis | N.m. | rEEG | Qualitative | 10-20 system | Most patients showed a physiological EEG; 1 patient showed generalized paroxysmal spike wave bursts; 4 patients showed diffuse slow activity during delirium tremens, partly accompanied by rhythmic bilateral slow waves |
Azabou et al. (2015) [43] | PLoS One | Prospective | 110 (22/88) | 63,8 | 29 | Sepsis | N.m. | Substance abuse reported but NOT considered in analysis | CAM | rEEG | Qualitative | 10-20 system, 13 channels | Absence of EEG reactivity, delta-predominant background, PDs, Synek grade ≥ 3, and Young grade > 1 at day 1 to 3 after admission were predictors of ICU mortality and associated with delirium; ESZ and PDs in about 20% of all patients |
Evans et al. (2017) [44] | Clin Neurophysiol | Prospective | 12 (3/9) | 66,8 | 42 | Surgery | No subjects with dementia | No patients with substance abuse | CAM, DRS | cEEG | Quantitative | 0.1 Hz high pass filter, 70 Hz low pass filter, EMG | Diminished total sleep time and longer latency to sleep onset during first night in hospital associated with greater delirium severity on day 2 after surgery; Delirious patients slept 2.4 h less and took 2 h longer to fall asleep than non-delirious patients; Greater waking EEG delta power on day 1 after surgery and less non-REM sleep EEG delta power on night 2 predicted delirium severity on day 2 after surgery |
Fleischmann et al. (2019) [45] | Clin EEG Neurosci | Retrospective | 376 (31/345) | 75,3 | 39 | Mixed | Mixed collective - dementia NOT considered in analysis | N.m. | CAM | rEEG | Quantitative | 10-20 system, 256 Hz sampling rate, 70 Hz low pass filter, 50 Hz notch filter | Differentiation of delirious patients vs. normal controls using spectral power at F3-P4 at 2 Hz and C3-O1 at 19 Hz achieved 100% sensitivity and 99% specificity |
Fleischmann et al. (2019) [45] | Pilot Feasibility Stud | Retrospective | 543 (129/414) | 73,6 | 43 | Mixed | N.m. | N.m. | DSM/ ICD | rEEG | Quantitative | 10-20 system, 256 Hz sampling rate; 50 Hz discrete FT filter | Significant differences in delirious and non-delirious patients in EEG power, connectivity, and network characteristics; Global alpha and regional beta band disconnectivity as well as theta band hyperconnectivity in delirious patients; Abnormalities affected networks engaged in consciousness, attention, memory, executive control, and salience detection |
Hunter et al. (2020) [46] | AIMS Neurosci | Prospective | 10 (5/5) | 63,8 | 20 | Mixed | No subjects with dementia | N.m. | CAM | rEEG | Quantitative | 10-20 system, 0.16-52 Hz band pass filter, 9 channels | EEG slowing as well as general loss of directed functional connectivity between recording sites in delirious patients; 3 electrodes were sufficient to differentiate groups, with significantly higher slow-to-fast frequency power ratio in delirious compared to non-delirious patients in C3, P3, T7, or all 3 |
Jacobson et al. (1993) [47] | J Neurol Neurosurg Psychiatry | Retrospective | 34 (18/16) | 76,6 | 65 | Mixed | Mixed collective - dementia considered in analysis | No patients with substance abuse | DSM/ ICD | rEEG | Qualitative & quantitative | 10-20 system, 16 channels + eye movement | Differentiation of normal vs. encephalopathic records using MMSE scores and relative power in the alpha frequency (up to 94% correctly classified; no sensitivity/specificity provided); Differentiation of patients with delirium vs. patients with dementia using EEG theta activity, relative power in delta, and brain map rating (up to 93% correctly classified) |
Jacobson et al. (1993) [47] | Biol Psychiatry | Prospective | 33 (15/18) | 75 | 73 | N.m. | Mixed collective - dementia considered in evaluation | No patients with substance abuse | DSM/ ICD | rEEG | Qualitative & quantitative | 10-20 system, 16 channels + eye movement | In delirious patients, changes in score of relative power map and changes in relative power in the alpha band significantly associated with changes in MMSE; In patients with dementia only, changes in score for absolute power maps and changes in absolute power in the delta band were significantly associated with changes in MMSE |
Katz et al. (1991) [48] | Int Psychogeriatr | Prospective | 28 (10/18) | N.m. | N.m. | N.m. | N.m. | N.m. | N.m. | cEEG | Quantitative | 10-20 system, 6 channels | Significantly differences in theta and beta power between delirious and non-delirious patients during hospitalization; Significant differences in subsequent change of theta, delta, and alpha power between delirious and non-delirious patients |
Keijzer et al. (2020) [49] | Resuscitation | Prospective | 141 (47/94) | 61,7 | 16 | Cardiac arrest | N.m. | N.m. | DSM/ ICD | cEEG | Quantitative | 10-20 system, 500 Hz sampling rate, 0.5-30 Hz band pass filtered with Butterworth filter, 21 channels | Delirium associated with longer hospitalization, and more frequent discharge to rehabilitation center or nursing home; EEG predicted delirium with 91% specificity and 40% sensitivity |
Kimchi et al. (2019) [50] | Neurology | Prospective | 200 (121/79) | 59,2 | 43 | Mixed | No subjects with dementia | N.m. | CAM | rEEG | Qualitative | 10-20 system | Generalized theta or delta slowing were associated with delirium; EEG slowing correlated with delirium severity; EEG slowing was associated with longer hospitalizations, worse functional outcomes, and increased mortality |
Knauert et al. (2018) [51] | J Crit Care | Retrospective | 93 (93/0) | 56,2 | 48 | Mixed | No subjects with dementia | N.m. | Other | cEEG | Qualitative | 10-20 system, 17 channels + eye movement, EMG | Delirious patients without K-complexes or without sleep spindles had more severe encephalopathy and higher odds of death |
Koponen et al. (1989) [52] | J Neurol Neurosurg Psychiatry | Prospective | 70 (51/19) | 73,8 | 57 | Mixed | Mixed collective - dementia considered in analysis | No patients with substance abuse | DSM/ ICD | rEEG | Quantitative | 10-20 system, 70 Hz high frequency limit, 16 channels | Significantly reduced alpha power, increased theta and delta activity and slowing of the peak and mean frequencies in delirious compared to non-delirious patients; Alpha power and various ratio parameters correlated with MMSE score, and delta percentage and mean frequency with the lengths of delirium and hospitalization |
Matsushima et al. (1997) [53] | Biol Psychiatry | Prospective | 20 (10/10) | 53,1 | 20 | acute myocardial infarction. | N.m. | No patients with substance abuse | DSM/ ICD | rEEG | Qualitative & quantitative | 10-20 system, 16 channels + eye movement | Delirious patients showed slowing of background EEG activity, particularly on day 2 after admission, and many rapid group, and rapid superimposed on slow eye movements, particularly on day 3; From days 2 to 3, EEG showed improvement in consciousness, and eye tracking signs of anxiety and tension |
Naeije et al. (2014) [54] | Epilepsy Behav | Prospective | 64 (64/0) | 82 | 70 | N.m. | N.m. | N.m. | CAM | cEEG & rEEG | Qualitative | 10-20 system, 21 channels | cEEG detected NCSE in 28% and focal IEDs in 16% of delirious patients; rEEG detected NCSE in 6% and focal IEDs in 16% of delirious patients; History of cognitive impairment and use of antibiotics and hypernatremia associated with NCSE; NCSE associated with longer hospitalization and higher mortality rate |
Nielsen et al. (2019) | Neurocrit Care | Prospective | 102 (66/36) | 71 | 33 | Mixed | N.m. | N.m. | CAM | cEEG | Qualitative & quantitative | 10-20 system, 1 kHz sampling rate, 1-120 Hz band pass filter, 19 channels + eye movement, EMG | Absence of delirium associated with preserved high-frequency beta activity and cEEG reactivity; Delirium associated with preponderance of low-frequency cEEG activity and absence of high-frequency cEEG activity; Sporadic PDs in 15 patients, 13 of which were delirious; No patient showed evidence of NCSE |
Numan et al. (2017) [55] | Clin Neurophysiol | Prospective | 58 (18/40) | 75,3 | 53 | Surgery | N.m. | N.m. | DSM/ ICD | cEEG | Quantitative | 10-20 system, 512 sampling rate, 0.15 Hz high pass filter, 70 Hz low pass filter, 21 channels | Significantly lower average PLI in patients with delirium or recovery from anesthesia compared to non-delirious patients; Loss of anterior-posterior information flow in alpha band in patients with delirium or recovery from anesthesia; Significantly lower functional connectivity in alpha band in patients with delirium or recovery from anesthesia compared to non-delirious patients; 77% sensitivity and 85% specificity in discrimination of delirious vs. non-delirious patients; 78% sensitivity and 68% specificity for patients with delirium vs. recovery from anesthesia |
Numan et al. (2019) [56] | Br J Anaesth | Prospective | 159 (55/104) | 76,9 | 33 | Surgery | Mixed collective - dementia NOT considered in analysis | Substance abuse reported but NOT considered in analysis | DSM/ ICD, CAM, DRS | rEEG | Quantitative | 10-20 system, 512 Hz sampling rate, 50 Hz notch filter, 0.15 Hz IIR filter, 4 channels | Depending on the cut-off, relative delta power predicted delirium with up to 90% sensitivity and up to 90% specificity (AUROC: 0.75) based on just one minute artifact-free EEG recording |
Plaschke et al. (2007) [57] | Anaesthesia | Prospective | 37 (17/20) | 63,7 | 27 | Mixed | No subjects with dementia | No patients with substance abuse | CAM | rEEG | Quantitative | 10-20 system, 0.5 Hz high pass filter, 16 channels | Significantly higher theta power and lower alpha power in delirious compared to non-delirious patients; No group differences in SAA |
Reischies et al. (2005) [58] | Psychiatry Res | Prospective | 12 (12/0) | 56,7 | 58 | treatment-resistant major depression | N.m. | N.m. | DSM/ ICD, DRS | rEEG | Quantitative | 10-20 system, 250 Hz sampling rate, 0.15-50 Hz band pass filter, 50 Hz notch filter, 0.5 Hz high pass filter, 32 channels + eye movement | Compared to baseline, significant increases in delta and theta power and decrease in alpha power during delirium; Decrease of theta activity at Fz in following 24 h correlated with recovery of awareness and performance of free recall; Source analysis with LORETA indicated that the main generators of the theta excess during delirium were localized in the anterior cingulate cortex and right fronto-temporal areas |
Sambin et al. (2019) [59] | Front Neurol | Prospective | 50 (50/0) | 84 | 66 | Mixed | Mixed collective - dementia considered in analysis | Substance abuse reported and considered in analysis | CAM | cEEG | Qualitative | 10-20 system, 21 channels | NCSE in 12% and interictal discharges in 30% of delirious patients |
Sun et al. (2019) [60] | NPJ Digit Med | Prospective | 174 (N.m./ N.m.) | N.m. | 33 | Mixed | No subjects with dementia | N.m. | CAM | N.m. | N.m. | N.m. | Deep learning model achieved detected delirium with 69% sensitivity and 83% specificity |
Tanabe et al. (2020) [61] | Br J Anaesth | Prospective | 70 (22/48) | 70,4 | 39 | Surgery | N.m. | N.m. | CAM, DRS | rEEG | Quantitative | 0.1-50 Hz band pass filter with Hamming windowed-sinc FIR filter, 256 channels | Preoperatively, patients with postoperative delirium had significantly higher alpha power, higher alpha band connectivity, but impaired structural connectivity; Postoperatively, delirium was associated with increased SWA in parieto-occipital and frontal cortex, with accompanying breakdown in functional connectivity; Changes in connectivity correlated with SWA, delirium severity, interleukin-10, and monocyte chemoattractant protein-1 |
Thomas et al. (2008) [62] | BMC Neurosci | Prospective | 61 (15/46) | 86,2 | 74 | Mixed | Mixed collective - dementia considered in analysis | N.m. | DSM/ ICD, CAM, DRS | rEEG | Qualitative & quantitative | 10-20 system, 500 Hz sampling rate, 0.03-70 Hz band pass filter, 32 channels, EMG | SAA not associated with delirium or cognitive functions; Occipital slowing, peak power and alpha decrease, delta and theta power increase, and slow wave ratio increase associated with delirium; EEG measures were correlated with cognitive performance and delirium severity, but not SAA |
Thomas et al. (2008) [63] | J Neurol Neurosurg Psychiatry | Prospective | 50 (12/38) | 85,8 | 72 | Mixed | Mixed collective - dementia considered in analysis | N.m. | DSM/ ICD | rEEG | Qualitative & quantitative | 10-20 system, 500 Hz sampling rate, 0.03-70 Hz band pass filter, 32 channels, EMG | qEEG was substantially better than rEEG in differentiating patients with delirium and dementia, delirium only, and cognitively unimpaired subjects; Differentiation of patients with delirium vs. with delirium and dementia using qEEG variables activated upper alpha and delta power density with 67% sensitivity and 91% specificity; Differentiation of patients with delirium vs. cognitively unimpaired subjects using qEEG variables relative theta power density at rest with 83% sensitivity and 60% specificity |
Trzepacz et al. (1986) [64] | Int J Psychiatry Med | Prospective | 40 (12/28) | 40 | 62 | Liver Disease | Mixed collective - dementia NOT considered in analysis | Substance abuse reported but NOT considered in analysis | DSM/ ICD | rEEG | Qualitative | N.m. | Delirium associated with serum albumin < 3.0 g/dl, MMSE scores < 24, impairment in TMT-A and -B, EEG dysrhythmia; In a subsample, differentiation between delirious and non-delirious patients using MMSE, TMT-A and -B, EEG, and albumin with 100% specificity and 100% sensitivity |
Trzepacz et al. (1988) [65] | Biol Psychiatry | Prospective | 108 (18/90) | 41 | 65 | Liver Disease | N.m. | Substance abuse reported but NOT considered in analysis | DSM/ ICD | rEEG | Qualitative | 10-20 system, 16 or 17 channels | Significantly slower dominant posterior rhythm, lower serum albumin, and worse scores in TMT-A and -B and MMSE in delirious compared to non-delirious patients; Differentiation between delirious and non-delirious patients using TMT-B, EEG, and albumin with 98% specificity and 83% sensitivity |
Trzepacz et al. (1989) [66] | J Neuropsychiatry Clin Neurosci | Prospective | 46 (23/23) | 40,4 | 60 | Liver Disease | N.m. | Substance abuse reported but NOT considered in analysis | DSM/ ICD | rEEG | Quantitative | 10-20 system, 120 Hz sampling rate, 4 channels | Significantly worse performance in MMSE, TMT-A and -B, and lower mean peak activity in delirious compared to non-delirious patients; Mean auditory brainstem evoked potentials were abnormal in both groups, with delirious patients showing a bimodal distribution of latency values and a greater proportion of abnormal values; somatosensory evoked potentials were abnormal only for delirious patients |
Trzepacz et al. (1989) [66] | Psychosomatics | Prospective | 247 (46/201) | 41,3 | 63 | Liver Disease | Mixed collective - dementia NOT considered in analysis | Substance abuse reported but NOT considered in analysis | DSM/ ICD | rEEG | Qualitative | 10-20 system, 16 or 17 channels | Significantly lower serum albumin, more EEG dysrhythmia, and worse performance in MMSE, TMT-A and -B in delirious compared to non-delirious patients; Delirious patients had significantly poorer adaptive functioning and lower occupational, family, and social scale ratings |
Vacas et al. (2016) [67] | Anesth Analg | Prospective | 23 (8/15) | 68 | N.m. | Mixed | N.m. | N.m. | DSM/ ICD, CAM | cEEG | Qualitative | 10-20 system, 2500 Hz sampling rate; 0.3-35 Hz band pass filter, 4 channels + eye movement, EMG | Moderate agreement between SedLine and polysomnography monitoring; No differences in delirium occurrence in patients with and without sleep disruption |
van Dellen et al. (2014) [68] | Anesthesiology | Prospective | 49 (25/24) | 75,1 | 45 | Surgery | No subjects with dementia | N.m. | DSM/ ICD, CAM | rEEG | Quantitative | 10-20 system, 512 Hz sampling rate, 0.15 Hz high pass filter, 21 channels | Significantly lower mean PLI in the alpha band in delirious compared to non-delirious patients; Network topology in delirious patients characterized by lower normalized weighted shortest path lengths in the alpha band; Significantly lower delta band dPLI in anterior regions and higher in central regions in delirious compared to non-delirious patients |
van der Kooi et al. (2015) [35] | Chest | Prospective | 56 (28/28) | 75,5 | 43 | Surgery | No subjects with dementia | N.m. | DSM/ ICD, CAM | rEEG | Quantitative | 10-20 system, 512 Hz sampling rate; 0.5-30 Hz band pass filter, 21 channels + eye movement | Differentiation of delirious vs. non-delirious patients using relative delta power from 1 min artifact-free recording of electrodes F8-Pz with 100% sensitivity and 96% specificity |
van Sweden, Mellerio (1989) [69] | Biol Psychiatry | Prospective | 16 (16/0) | 50,8 | 69 | Intoxication/ Withdrawal | N.m. | Substance abuse reported and considered in analysis | N.m. | rEEG | Qualitative | N.m. | All delirious patients had non-convulsive paroxysmal EEG disturbances without a history of epilepsy |