In dystonic and spastic movement disorders, however different in their pathophysiological mechanisms, a similar impairment of sensorimotor control with special emphasis on afferentation is assumed. Peripheral intervention on afferent inputs evokes plastic changes within the central sensorimotor system. Intramuscular application of botulinum toxin type A (BoNT-A) is a standard evidence-based treatment for both conditions. Apart from its peripheral action on muscle spindles, a growing body of evidence suggests that BoNT-A effects could also be mediated by changes at the central level including cerebral cortex. We review recent studies employing electrophysiology and neuroimaging to investigate how intramuscular application of BoNT-A influences cortical reorganization. Based on such data, BoNT-A becomes gradually accepted as a promising tool to correct the maladaptive plastic changes within the sensorimotor cortex. In summary, electrophysiology and especially neuroimaging studies with BoNT-A further our understanding of pathophysiology underlying dystonic and spastic movement disorders and may consequently help develop novel treatment strategies based on neural plasticity.
1 May 2014 in Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques
Objective: To identify predictors of good outcome in acute basilar artery occlusion (BAO).Background: Acute ischemic stroke (AIS) caused by BAO is often associated with a severe and persistent neurological deficit and a high mortality rate.Methods: The set consisted of 70 consecutive AIS patients (51 males; mean age 64.5±14.5 years) with BAO. The role of the following factors was assessed: baseline characteristics, stroke risk factors, pre-event antithrombotic treatment, neurological deficit at time of treatment, estimated time to therapy procedure initiation, treatment method, recanalization rate, change in neurological deficit, post-treatment imaging findings. 30- and 90-day outcome was assessed using the modified Rankin scale with a good outcome defined as a score of 0–3.Results: The following statistically significant differences were found between patients with good versus poor outcomes: mean age (54.2 vs. 68.9 years; p=0.0001), presence of arterial hypertension (52.4% vs. 83.7%; p=0.015), diabetes mellitus (9.5% vs. 55.1%; p=0.0004) and severe stroke (14.3% vs. 65.3%; p=0.0002), neurological deficit at time of treatment (14.0 vs. 24.0 median of National Institutes of Health Stroke Scale [NIHSS] points; p=0.001), successful recanalization (90.0% vs. 54.2%; p=0.005), change in neurological deficit (12.0 vs. 1.0 median difference of NIHSS points; p=0.005). Stepwise binary logistic regression analysis identified age (OR=0.932, 95% CI=0.882–0.984; p=0.012), presence of diabetes mellitus (OR=0.105, 95% CI=0.018–0.618; p=0.013) and severe stroke (OR=0.071, 95% CI=0.013–0.383; p=0.002) as significant independent negative predictors of good outcome.Conclusions: In the present study, higher age, presence of diabetes mellitus and severe stroke were identified as significant independent negative predictors of good outcome.
Post-stroke spasticity (PSS) is effectively treated with intramuscular botulinum toxin type A (BoNT-A), although the clinical improvement is likely mediated by changes at the central nervous system level. Using functional magnetic resonance imaging (fMRI) of the brain, this study aims to confirm and locate BoNT-A-related changes during motor imagery with the impaired hand in severe PSS. Temporary alterations in primary and secondary sensorimotor representation of the impaired upper limb were expected. Thirty chronic stroke patients with upper limb PSS undergoing comprehensive treatment including physiotherapy and indicated for BoNT treatment were investigated. A change in PSS of the upper limb was assessed with the modified Ashworth scale (MAS). fMRI and clinical assessments were performed before (W0) and 4 weeks (W4) and 11 weeks (W11) after BoNT-A application. fMRI data were acquired using 1.5-Tesla scanners during imagery of finger-thumb opposition sequences with the impaired hand. At the group level, we separately modeled (1) average activation at each time point with the MAS score and age at W0 as covariates; and (2) within-subject effect of BoNT-A and the effect of time since W0 as independent variables. Comprehensive treatment of PSS with BoNT-A significantly decreased PSS of the upper limb with a maximal effect at W4. Task-related fMRI prior to treatment (W0) showed extensive activation of bilateral frontoparietal sensorimotor cortical areas, bilateral cerebellum, and contralesional basal ganglia and thalamus. After BoNT-A application (W4), the activation extent decreased globally, mostly in the bilateral parietal cortices and cerebellum, but returned close to baseline at W11. The intra-subject contrast revealed a significant BoNT-A effect, manifesting as a transient decrease in the activation of the ipsilesional intraparietal sulcus and superior parietal lobule. We demonstrate that BoNT-A treatment of PSS of the upper limb is associated with transient changes in the ipsilesional posterior parietal cortex, possibly resulting from temporarily altered sensorimotor upper limb representations.
Intravenous thrombolysis (IVT) is considered an effective treatment for acute ischemic stroke (IS). However, not all treated patients may achieve good outcome. The aim was to evaluate whether the initial NIHSS and DWI infarct volume could be the predictors for good outcome after IVT. The set of 125 patients with consecutive hemispheric IS (78 men; mean age 66.0 ± 12.1 years) treated with IVT within 3 h was analyzed. DWI volume was measured on admission. Good outcome was defined as a score 0-2 in modified Rankin Scale. Multivariate logistic regression analysis showed initial NIHSS as an independent predictor of good outcome (P = 0.001). ROC curves showed baseline NIHSS ≤13.5 points and DWI volume ≤13.7 ml as cut-offs related to good outcome. The initial NIHSS and DWI volume might be the predictors for good clinical outcome in acute stroke patients treated with IVT. The initial NIHSS score seems to be more accurate.
15 February 2023 in Journal of the Neurological Sciences