TABLE 2.
EEG Findings Based on Confusion Assessment Method Defined Delirium
| Features | Total n = 407), n (%) | No Delirium (n = 132), n (%) | Delirium (n = 145), n (%) | Coma (n = 130), n (%) | Post Hoca |
|---|---|---|---|---|---|
| Any EEG abnormality | 348 (85.5) | 77 (58.3) | 141 (97.2) | 130 (100) | N < D, N < C |
| Background/rhythm abnormalities | |||||
| Absence of a normal posterior dominant rhythm | 279 (68.6) | 38 (28.8) | 114 (78.6) | 127 (97.7) | N < D < C |
| Absent sleep transients (spindles, K-complexes, vertex waves) | 350 (86.0) | 93 (70.5) | 131 (90.3) | 126 (96.9) | N < D, N < C |
| Asymmetry | 168 (41.3) | 41 (31.1) | 74 (51.0) | 53 (40.8) | N < D |
| Focal/unilateral theta slowing | 48 (11.8) | 14 (10.6) | 29 (20.0) | 5 (3.8) | D > C |
| Focal/unilateral delta slowing | 110 (27.0) | 35 (26.5) | 55 (37.9) | 20 (15.4) | D > C |
| Lateralized rhythmic delta activity | 18 (4.4) | 4 (3.0) | 8 (5.5) | 6 (4.6) | NS |
| Generalized rhythmic delta activity | 52 (12.8) | 10 (7.6) | 20 (13.8) | 22 (16.9) | NS |
| Generalized/diffuse theta slowing | 230 (56.5) | 45 (34.1) | 107 (73.8) | 78 (60.0) | N < D > C |
| Generalized/diffuse delta slowing | 223 (54.8) | 29 (22.0) | 91 (62.8) | 103 (79.2) | N < D < C |
| Excess/diffuse alpha | 27 (6.6) | 5 (3.8) | 8 (5.5) | 14 (10.8) | NS |
| Excess/diffuse beta | 37 (9.1) | 12 (9.1) | 7 (4.8) | 18 (13.8) | D < C |
| Extreme delta brush | 1 (0.2) | 0 (0.0) | 0 (0.0) | 1 (0.8) | NS |
| Brief potentially ictal rhythmic discharges | 1 (0.2) | 1 (0.8) | 0 (0.0) | 0 (0.0) | NS |
| Intermittent brief attenuation | 22 (5.4) | 0 (0.0) | 6 (4.1) | 16 (12.3) | N < C, D < C |
| Low voltage: moderate (< 20 μV) | 20 (4.9) | 2 (1.5) | 6 (4.1) | 12 (9.2) | N < C |
| Low voltage: extreme/electrocerebral silence | 5 (1.2) | 0 (0.0) | 0 (0.0) | 5 (3.8) | NS |
| Burst suppression with epileptiform activity | 9 (2.2) | 0 (0.0) | 0 (0.0) | 9 (6.9) | N < C, D < C |
| Burst suppression without epileptiform activity | 16 (3.9) | 0 (0.0) | 0 (0.0) | 16 (12.3) | N < C, D < C |
| Unreactive EEG | 17 (4.2) | 0 (0.0) | 3 (2.1) | 14 (10.8) | N < C, D < C |
| Periodic discharges | |||||
| Lateralized periodic discharges | 44 (10.8) | 8 (6.1) | 17 (11.7) | 19 (14.6) | NS |
| GPDs: not triphasic | 61 (15.0) | 0 (0.0) | 16 (11.0) | 45 (34.6) | N < D < C |
| GPDs: triphasic | 13 (3.2) | 0 (0.0) | 7 (4.8) | 6 (4.6) | N < D, N < C |
| TWs | 13 (3.2) | 0 (0.0) | 7 (4.8) | 6 (4.6) | N < D, N < C |
| GPDs (with or without triphasic morphology) or TWs | 62 (15.2) | 0 (0.0) | 17 (11.7) | 45 (34.6) | N < D < C |
| BIPDs | 8 (2.0) | 0 (0.0) | 3 (2.1) | 5 (3.8) | NS |
| GPDs or BIPDs | 64 (15.7) | 0 (0.0) | 18 (12.4) | 46 (35.4) | N < D < C |
| Sporadic discharges | |||||
| Sporadic discharges (focal or generalized) | 109 (26.8) | 13 (9.8) | 51 (35.2) | 45 (34.6) | N < D, N < C |
| Seizure activity | |||||
| Discrete seizures: focal | 17 (4.2) | 6 (4.5) | 5 (3.4) | 6 (4.6) | NS |
| Discrete seizures: generalized | 2 (0.5) | 0 (0.0) | 1 (0.7) | 1 (0.8) | NS |
| NCSE: focal | 1 (0.2) | 1 (0.8) | 0 (0.0) | 0 (0.0) | NS |
| NCSE: generalized | 1 (0.2) | 0 (0.0) | 0 (0.0) | 1 (0.8) | NS |
BIPD = bilateral independent periodic discharge, C = coma, D = delirium, GPD = generalized periodic discharge, N = no delirium, NCSE = nonconvulsive status epilepticus, NS = not significant, TW = triphasic wave.
aCategorical data are reported as n = counts (percent) and compared using χ2 tests, followed by paired comparisons with Bonferroni correction. The significance level was set at p < 0.05. We show the pairwise results from the post hoc comparison. If NS, the omnibus p is NS.