Microstructural changes in the brain after long-term post-concussion symptoms: A randomized trial

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.

Design of an early intervention for persistent post-concussion symptoms in adolescents and young adults: A feasibility study

BACKGROUND

About 5-15 % of patients with concussion experience persistent post-concussion symptoms (PCS) longer than 3 months post-injury.

OBJECTIVE

To explore the feasibility of a new intervention for young patients with persistent PCS and long-term changes after intervention.

METHODS

Thirty-two consecutive patients (15-30 years) with persistent PCS 2-4 months post-injury were recruited from a cohort study or referred to a non-randomized feasibility study of an individually tailored, 8-week, multidisciplinary intervention. Assessment was performed at baseline, end of intervention (EOI), and at 3- and 12-month follow-up (FU). Main measures were The Experience of Service Questionnaire (ESQ), Rivermead Post-Concussion Symptoms Questionnaire (RPQ) and The Quality of Life after Brain Injury - Overall Scale (QOLIBRI-OS).

RESULTS

Twenty-three (72%) patients completed the intervention. The ESQ demonstrated high patient satisfaction. There was a decrease of PCS and an increase in quality of life from baseline to EOI: RPQ score -8.9 points, 95% CI 4.5 to 13.3, p < 0.001; QOLIBRI-OS score +10.5 points, 95% CI 2.5 to 18.5, p = 0.010. Improvement was maintained at 3- and 12-month FU.

CONCLUSION

The new early intervention is feasible and may prevent chronification of PCS. An RCT is currently performed to evaluate the effect of the intervention.

The role of the microcirculation in delayed cerebral ischemia and chronic degenerative changes after subarachnoid hemorrhage

The mortality after aneurysmal subarachnoid hemorrhage (SAH) is 50%, and most survivors suffer severe functional and cognitive deficits. Half of SAH patients deteriorate 5 to 14 days after the initial bleeding, so-called delayed cerebral ischemia (DCI). Although often attributed to vasospasms, DCI may develop in the absence of angiographic vasospasms, and therapeutic reversal of angiographic vasospasms fails to improve patient outcome. The etiology of chronic neurodegenerative changes after SAH remains poorly understood. Brain oxygenation depends on both cerebral blood flow (CBF) and its microscopic distribution, the so-called capillary transit time heterogeneity (CTH). In theory, increased CTH can therefore lead to tissue hypoxia in the absence of severe CBF reductions, whereas reductions in CBF, paradoxically, improve brain oxygenation if CTH is critically elevated. We review potential sources of elevated CTH after SAH. Pericyte constrictions in relation to the initial ischemic episode and subsequent oxidative stress, nitric oxide depletion during the pericapillary clearance of oxyhemoglobin, vasogenic edema, leukocytosis, and astrocytic endfeet swelling are identified as potential sources of elevated CTH, and hence of metabolic derangement, after SAH. Irreversible changes in capillary morphology and function are predicted to contribute to long-term relative tissue hypoxia, inflammation, and neurodegeneration. We discuss diagnostic and therapeutic implications of these predictions.