Lack of hemispheric dominance for consciousness in acute ischaemic stroke

Abstract

Background: Previous reports have suggested left hemispheric dominance for maintaining consciousness, although there is controversy over this claim. Objective: To compare early impairment of level of consciousness between patients with right and left hemispheric stroke. Methods: Data from 564 patients with ischaemic stroke enrolled in the placebo arm of a trial of a putative neuroprotectant were analysed. All patients had major hemispheric stroke with cortical dysfunction, visual field deficit, and limb weakness, with symptom onset within 12 hours of enrolment. Patients were prospectively evaluated on a predefined scale (1-6; 1 = fully awake, higher scores representing greater impairment) to measure level of consciousness at multiple time points over the initial 24 hours after presentation. The National Institutes of Health (NIH) stroke scale score at presentation and infarct volume at 30 days were determined. Results: Some degree of impairment in level of consciousness was observed in 409 of the 564 patients (73%). Median maximum sedation score was 2 for both right and left hemispheric stroke (p = 0.91). Mean sedation score over 24 hours was 1.5 for both right and left stroke (p = 0.75). There was no difference between level of consciousness scores in right and left stroke at any individual time point during the 24 hour monitoring period. No association between side and impairment in level of consciousness was seen after adjustment for stroke severity and infarct volume. Conclusions: In contrast to previous reports, there was no evidence for hemispheric dominance for consciousness in the setting of a major hemispheric stroke.

Strokes after cardiac surgery: mostly right hemispheric ischemic with mild residual damage

“…[Dano, unpublished data, 2004]. Moreover, out of 564 patients with stroke admitted at Pennsylvania Medical Center, stroke involved the right hemisphere in 261 patients (46 %) and the left in 299 (53 %) [6]. The fact that most of our patients developed strokes immediately after operations including valve repair/other procedures might suggest an embolic, procedure-related mechanism.…”

“…22), 7.3 for the left hemispheric (range[3][4][5][6][7][8][9][10][11][12][13][14], and 15 for the vertebrobasilar strokes (range 4-23). Two patients died in hospital, both with vertebrobasilar stroke.…”

The impact of lesion side on acute stroke treatment

“…When reported, the numbers favor the left hemisphere. The left:right was 1.08 in the placebo arm of the National Institute of Neurologic Disorders and Stroke trial 3 ; 1.12 in patients with acute stroke who were seen by the stroke service at Beth Israel Deaconess Medical Centre 4 ; 1.14 in the placebo arm of the CLASS-I trial 19 ; and 1.2 in the rt-PA registry of the Helsinki University Central Hospital. 20 We tested in the RCSN the following hypotheses: 1) right hemispheric strokes are less frequent than left hemispheric ones; 2) admission/assessment of right hemispheric strokes is delayed; 3) stroke severity is underestimated in patients with right hemispheric strokes; and 4) patients with strokes affecting the right hemisphere have a more severe deficit and a longer hospital stay.…”

Recommendations for the Management of Cerebral and Cerebellar Infarction With Swelling

“…34 Although right hemisphere infarction may result in a flattened affect, complete infarction of either hemisphere itself is rarely associated with diminished arousal. 35 Responsiveness, however, is diminished early in combined MCA and anterior cerebral artery infarctions. Cerebral ptosis (apraxia of eyelid opening) may be present and falsely suggest a decreased level of consciousness.…”