Deep structural brain lesions associated with consciousness impairment early after hemorrhagic stroke

Abstract

The purpose of this study was to determine the significance of deep structural lesions for impairment of consciousness following hemorrhagic stroke and recovery at ICU discharge. Our study focused on deep lesions that previously were implicated in studies of disorders of consciousness. We analyzed MRI measures obtained within the first week of the bleed and command following throughout the ICU stay. A machine learning approach was applied to identify MRI findings that best predicted the level consciousness. From 158 intracerebral hemorrhage patients that underwent MRI, one third was unconscious at the time of MRI and half of these patients recovered consciousness by ICU discharge. Deep structural lesions predicted both, impairment and recovery of consciousness, together with established measures of mass effect. Lesions in the midbrain peduncle and pontine tegmentum alongside the caudate nucleus were implicated as critical structures. Unconscious patients predicted to recover consciousness by ICU discharge had better long-term functional outcomes than those predicted to remain unconscious.

Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1

Hemorrhage and edema volumes and midline shift. Panel A. Illustrates the volume on MRIs of one exemplary case. Panel B. Measurements according to consciousness level at time of MRI (normalized values; for details please refer to methods). ICH: Intracerebral Hemorrhage; MLS: midline shift.

Figure 2

Flow chart. Level of consciousness assessed at MRI and ICU discharge. Note that for the 5 patients who died in the ICU, we considered the last neurological exam as the assessment at ICU discharge (of those that died, 3 patients were unconscious and 2 conscious at time of MRI, all of them were unconscious prior to death).

Figure 3

Location of hemorrhages according to consciousness level. Prevalence of ICH observed on MRI are shown by level of consciousness at the time of the MRI and on hospital discharge in three groups: (1) patients that were conscious both at time of MRI and at discharge, (2) patients that were unconscious at the time of MRI and were conscious by the time of ICU discharge, (3) and patients that were unconscious at the time of MRI and remained unconscious by the time of ICU discharge. Patients that were conscious at the time of MRI but unconscious on ICU discharge are not displayed (N = 6). (“unconscious”: patients did not follow or mimic even simple commands; “conscious”: patients followed or mimicked simple commands. “ipsi” and “contra” stand for ipsilateral and contralateral with respect to the primary side of the hemorrhage; Cx: cortex.

Figure 4

Functional outcome in patients unconscious at MRI. Displayed are the 3-month GOS-E scores in unconscious patients that were predicted to be conscious or unconscious at ICU discharge. Unconscious patients at time of MRI that were predicted to be conscious at ICU discharge (N = 43) based on imaging findings were more likely to be conscious at ICU discharge and had a greater chance to reach a GOS-E ≥ 4 at 3 months (illustrated in shades of green; p-value = 0.02). GOS-E: Glasgow Outcome Scale – revised; NA: not available (lost follow-up).