Prognostic Factors of Functional Recovery from Left Hemispheric Stroke

Disruption of Resting-State Functional Connectivity in Acute Ischemic Stroke: Comparisons Between Right and Left Hemispheric Insults

Few resting-state functional magnetic resonance imaging (RS-fMRI) studies evaluated the impact of acute ischemic changes on cerebral functional connectivity (FC) and its relationship with functional outcomes after acute ischemic stroke (AIS), considering the side of lesions. To characterize alterations of FC of patients with AIS by analyzing 12 large-scale brain networks (NWs) with RS-fMRI. Additionally, we evaluated the impact of the side (right (RH) or left (LH) hemisphere) of insult on the disruption of brain NWs. 38 patients diagnosed with AIS (17 RH and 21 LH) who performed 3T MRI scans up to 72 h after stroke were compared to 44 healthy controls. Images were processed and analyzed with the software toolbox UF2C with SPM12. For the first level, we generated individual matrices based on the time series extraction from 70 regions of interest (ROIs) from 12 functional NWs, constructing Pearson's cross-correlation; the second-level analysis included an analysis of covariance (ANCOVA) to investigate differences between groups. The statistical significance was determined with p < 0.05, after correction for multiple comparisons with false discovery rate (FDR) correction. Overall, individuals with LH insults developed poorer clinical outcomes after six months. A widespread pattern of lower FC was observed in the presence of LH insults, while a contralateral pattern of increased FC was identified in the group with RH insults. Our findings suggest that LH stroke causes a severe and widespread pattern of reduction of brain networks' FC, presumably related to the impairment in their long-term recovery.

Predictors of ambulatory recovery and walking proficiency in community-dwelling stroke survivors: a cross-sectional study

Background

Although the major goal of rehabilitation is to return a stroke survivor (SSv) to as close to their pre-stroke functioning, limitation in ambulatory recovery and walking proficiency is the major impediment. Despite the importance of walking to the outcomes in stroke, factors predicting its recovery remain unclear. This study therefore was aimed at exploring the predictors of ambulatory recovery and walking proficiency in community-dwelling SSv.

Methods

This study involved 164 (83females) SSv from four tertiary health institutions in Nigeria. Ambulatory level and status was assessed using Functional Ambulatory Classification, motor function using the Fugl-Myer Assessment scale (lower limb), and ambulatory/waking endurance using the 6-min walk test. Ambulatory capability was assessed using the Lower Extremity Functional Scale, ambulatory self-confidence using the Ambulatory Self-Confidence Questionnaire, and functional ambulatory profile using the Modified Emory Functional Ambulation Profile. Mobility was assessed using the Modified Rivermead Mobility Index, functional mobility using Time Up and Go, balance using the Berg Balance Scale, and cognitive function using the modified Mini-Mental State Examination. Spatial indexes were assessed using the Footprint method and temporal variables using a stopwatch and gait speed on a 10-m walkway. Data was analyzed using multiple regression analysis at p ≤ 0.05.

Results

Participants (mean age = 54.3±11.36 years) have had stroke for 12.9 ± 17.39 months and spent 9.82 ± 13.19 months in hospital admissions. More (65.2%) had ischemic stroke with 54.3% of them having left hemispheric stroke. The predictors of ambulatory onset in SSv were stroke duration and length of stay in hospital admission contributing 40.3% (β = 0.403) and 17.6% (β = 0.176) respectively to the variance. Mobility (β = 0.249, p < 0.001), gait speed (β = 0.185, p = 0.012), paretic double-limb support time (β = 0.155, p = 0.03), balance (β = 0.334, p < 0.001), and cognition (β = 0.155, p = 0.01) were predictors of ambulatory self-confidence contributing 59.5% to the variance. Balance (β = 0.363, p < 0.001) and mobility (β = 0.155, p = 0.015) were predictors of ambulatory capability contributing 52.9% to the variance. Balance (β = −0.489, p < 0.001), paretic double-limb support time (β = 0.223, p = 0.003), gait speed (β = −0.181, p = 0.022), and paretic swing phase duration (β = 0.177, p = 0.01) were predictors of functional ambulatory profile (p < 0.05) contributing 52.9% to the variance. Gait speed (β = −0.648, p < 0.001) and step length (β = −0.157, p = 0.003) were predictors of walking endurance contributing 76.5% to the variance.

Conclusion

Ambulatory recovery and walking proficiency depend on the interplay among duration of stroke and length of hospitalization on the one hand and balance performance, cognitive function, and the spatiotemporal integrity of the affected limb on the other hand.

Structural Covariance of the Ipsilesional Primary Motor Cortex in Subcortical Stroke Patients with Motor Deficits

The analysis of structural covariance has emerged as a powerful tool to explore the morphometric correlations among broadly distributed brain regions. However, little is known about the interactions between the damaged primary motor cortex (M1) and other brain regions in stroke patients with motor deficits. This study is aimed at investigating the structural covariance pattern of the ipsilesional M1 in chronic subcortical stroke patients with motor deficits. High-resolution T1-weighted brain images were acquired from 58 chronic subcortical stroke patients with motor deficits (29 with left-sided lesions and 29 with right-sided lesions) and 50 healthy controls. Structural covariance patterns were identified by a seed-based structural covariance method based on gray matter (GM) volume. Group comparisons between stroke patients (left-sided or right-sided groups) and healthy controls were determined by a permutation test. The association between alterations in the regional GM volume and motor recovery after stroke was investigated by a multivariate regression approach. Structural covariance analysis revealed an extensive increase in the structural interactions between the ipsilesional M1 and other brain regions in stroke patients, involving not only motor-related brain regions but also non-motor-related brain regions. We also identified a slightly different pattern of structural covariance between the left-sided stroke group and the right-sided stroke group, thus indicating a lesion-side effect of cortical reorganization after stroke. Moreover, alterations in the GM volume of structural covariance brain regions were significantly correlated to the motor function scores in stroke patients. These findings indicated that the structural covariance patterns of the ipsilesional M1 in chronic subcortical stroke patients were induced by motor-related plasticity. Our findings may help us to better understand the neurobiological mechanisms of motor impairment and recovery in patients with subcortical stroke from different perspectives.

Prognostic factors of functional outcome in post-acute stroke in the rehabilitation unit

BACKGROUND/PURPOSE

This retrospective study aimed to determine which factors, such as cognition, motor recovery, swallowing function, and bladder and bowel functions, significantly predicted independence in the activities of daily living (ADL) at hospital discharge in a domestic population of patients experiencing post-acute stroke who received in-hospital rehabilitation.

METHODS

We reviewed medical records that were retrieved from the Integrated Medical Database, National Taiwan University Hospital (NTUH-iMD) of 3000 patients who suffered from stroke and were admitted to NTUH from 2014 to 2017. The main outcome measure was independence in the basic ADL (modified Barthel index [mBI]) at discharge. Regression analyses were used to identify prognostic factors for the basic ADL (mBI).

RESULTS

The total mBI improved from 40.7 ± 33.0 to 63.1 ± 34.1 in eligible 2538 patients during their hospital stay. The baseline daily activity function (R² change = 0.042) was the most important prognostic factor associated with independence at discharge, followed by dependence in sitting up (R² change = 0.014), impaired sitting balance (R² change = 0.010), the Brunnstrom stage of hemiplegic lower limb (R² change = 0.006), and the presence of bladder incontinence (R² change = 0.006) assessed by physician upon rehabilitation admission (R² = 0.53, p < 0.05). Dependency in sitting up, impaired sitting balance, and the presence of urinary incontinence were negative prognostic factors of ADL independence at discharge (p < 0.05). By contrast, the Brunnstrom stage of hemiplegic lower limb and baseline mBI scores at rehabilitation admission were positive prognostic factors of ADL independence at discharge (p < 0.05).

CONCLUSION

Baseline ADL function was the most important prognostic factor of functional independence in post-acute stroke. Moreover, the activity limitation of dependency on sitting up and motor function impairment of hemiplegic lower limb prognosticated functional independence.