RESUMO
A recent randomized controlled trial in young patients with long-term post-concussion symptoms showed that a novel behavioral intervention "Get going After concussIoN" is superior to enhanced usual care in terms of symptom reduction. It is unknown whether these interventional effects are associated with microstructural brain changes. The aim of this study was to examine whether diffusion-weighted MRI indices, which are sensitive to the interactions between cellular structures and water molecules' Brownian motion, respond differently to the interventions of the above-mentioned trial and whether such differences correlate with the improvement of post-concussion symptoms. Twenty-three patients from the intervention group (mean age 22.8, 18 females) and 19 patients from the control group (enhanced usual care) (mean age 23.9, 14 females) were enrolled. The primary outcome measure was the mean kurtosis tensor, which is sensitive to the microscopic complexity of brain tissue. The mean kurtosis tensor was significantly increased in the intervention group (p = 0.003) in the corpus callosum but not in the thalamus (p = 0.78) and the hippocampus (p = 0.34). An increase in mean kurtosis tensor in the corpus callosum tended to be associated with a reduction in symptoms, but this association did not reach significance (p = 0.059). Changes in diffusion tensor imaging metrics did not differ between intervention groups and were not associated with symptoms. The current study found different diffusion-weighted MRI responses from the microscopic cellular structures of the corpus callosum between patients receiving a novel behavioral intervention and patients receiving enhanced usual care. Correlations with improvement of post-concussion symptoms were not evident.
Assuntos
Concussão Encefálica/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Corpo Caloso/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Adulto , Encéfalo/ultraestrutura , Corpo Caloso/ultraestrutura , Imagem de Tensor de Difusão , Feminino , Humanos , Masculino , Distribuição AleatóriaRESUMO
INTRODUCTION: The contribution of hyperreflexia to impairment after stroke is debated. Spinal motoneuron excitability in healthy subjects and stroke patients with and without spasticity was compared. METHODS: Twenty-four patients with single stroke more than 6 months ago and 18 gender-matched healthy volunteers were included. Spasticity was assessed according to the Modified Ashworth Scale. Mmax amplitude and F wave frequency in the abductor pollicis brevis muscle were measured by electrical stimulation of the median nerve. RESULTS: Mmax values were comparable between the groups. However, patients with (n=7) and without (n=17) clinically evident spasticity had a significant increase in F wave frequency when compared with healthy subjects. F wave frequency did not differ between spastic and nonspastic patients. DISCUSSION: Increase in spinal motoneuron excitability after stroke is present in stroke patients with minor or no motor deficiencies and does not necessarily lead to spasticity.