Structural cerebellar reserve positively influences outcome after severe stroke

Abstract

The concept of brain reserve capacity positively influencing the process of recovery after stroke has been continuously developed in recent years. Global measures of brain health have been linked with a favourable outcome. Numerous studies have evidenced that the cerebellum is involved in recovery after stroke. However, it remains an open question whether characteristics of cerebellar anatomy, quantified directly after stroke, might have an impact on subsequent outcome after stroke. Thirty-nine first-ever ischemic non-cerebellar stroke patients underwent MRI brain imaging early after stroke and longitudinal clinical follow-up. Structural images were used for volumetric analyses of distinct cerebellar regions. Ordinal logistic regression analyses were conducted to associate cerebellar volumes with functional outcome 3-6 months after stroke, operationalized by the modified Rankin Scale. Larger volumes of cerebellar lobules IV, VI and VIIIB were positively correlated with favourable outcome, independent of the severity of initial impairment, age and lesion volume (P < 0.01). The total cerebellar volume did not exhibit a significant structure-outcome association. The present study reveals that pre-stroke anatomy of distinct cerebellar lobules involved in motor and cognitive functioning might be linked to outcome after acute non-cerebellar stroke, thereby promoting the emerging concepts of structural brain reserve for recovery processes after stroke.

Localized network damage related to white matter hyperintensities is linked to worse outcome after severe stroke

“…We already used this approach in two previous studies. 15,16 All patients were treated at the University Medical Center Hamburg-Eppendorf between 2012 and 2020. The final sample size comprised 33 datasets.…”

“…[11][12][13] WMH-related network damage could serve as a surrogate for pre-existing disturbances in brain networks, and it could be a novel approach to better understand the underlying mechanisms of brain reserve capacity 14 and outcome variability after stroke, as recently evidenced for cortical and cerebellar brain anatomy. 15,16 The present study sought to answer the question whether the extent of WMH-related network damage, quantified early after severe ischemic stroke, can explain outcome variability. To this end, clinical and structural brain imaging data of 33 severely affected acute stroke patients were analysed.…”

“…11-13 WMH-related network damage could serve as a surrogate for pre-existing disturbances in brain networks, and it could be a novel approach to better understand the underlying mechanisms of brain reserve capacity 14 and outcome variability after stroke, as recently evidenced for cortical and cerebellar brain anatomy. 15,16…”

Frontoparietal structural network disconnections correlate with outcome after a severe stroke

“…Lesion volumes were LOG 10 -transformed to improve data distribution. To address multicollinearity, we included lesion volume and NIHSS at T 1 after residualization against the regional disconnection, in line with recent studies 27,28 . Models were corrected for multiple comparisons via the Bonferroni-Holm false-discovery-rate (FDR) method and a leave-one-out analysis (LOOA) was applied to test the robustness of significant regional findings.…”

“…A subset of patients was not eligible for clinical testing at timepoint T2 and thus, data was only available after 6 months. This approach has been repeatedly used in our previous analyses which also give precise information regarding the cohorts' integration [26][27][28] . In this analysis, initial symptom burden was operationalized by the NIHSS score at T1, global disability at T2 was quantified by mRS.…”