Citations

Introduction Cerebellar transcranial direct current stimulation (tDCS) combined with language therapy can aid in chronic aphasia recovery, but the neural mechanisms and biomarkers of treatment efficacy remain uncertain. Methods In this secondary analysis of data from a previously conducted clinical trial, we used a randomized, double-blind, sham-controlled, within-subject crossover design with a study sample of 19 participants with post-stroke aphasia. We assessed the degree to which baseline properties of cerebro-cerebellar white matter tracts can predict or moderate longitudinal treatment effects at three time points: post-treatment, 2 weeks post-treatment, and 2 months post-treatment. Tract properties were measured by fractional anisotropy (FA) and mean diffusivity (MD) from diffusion tensor imaging (DTI). We also tested whether there are differential effects between trained and untrained language tasks and between cerebellar tDCS polarity (anodal and cathodal). Results Baseline measures of tracts connecting the left lesioned cortex to the right posterolateral cerebellum (stimulation target) influenced treatment gains for untrained tasks, relative to sham control. In contrast, for the trained task, treatment gains were influenced by baseline measures of tracts connecting the non-stimulated left cerebellum with the contralateral right cerebral cortex. Although there were no consistent effects from cerebellar tDCS polarity, a highly consistent pattern emerged across all tasks and tracts. Specifically, language improvements were predicted by a baseline tract profile (i.e., higher FA and lower MD) typically associated with higher white matter integrity, especially within the context of stroke-induced white matter decline. Discussion These findings corroborate the potential for baseline tract properties as a biomarker of treatment efficacy and support the notion that adjuvant (cerebellar tDCS + language) therapy preferentially benefits individuals with relatively preserved structural connections within functionally relevant networks. Clinical trial registration ClinicalTrials.gov , identifier (NCT02901574).

Four corner arthrodesis and proximal row carpectomy are the most common techniques for the management of advanced radiocarpal arthritis due to longstanding scapholunate instability and scaphoid nonunion. The advantages and short comings of each technique have been well defined in the literature. Advancements in joint replacement and arthroscopic surgery have resulted in new operations to manage radiocarpal and midcarpal arthritis. Most of these new procedures are modifications of the two classical operations, but some use modern implants and newer materials. New individualized options, like osteochondral grafting in combination with proximal row carpectomy or (arthroscopic) distal resection of the scaphoid, allowed us to improve our treatment and offer patients less invasive but equally effective procedures. We consider that four corner arthrodesis and proximal row carpectomy should not always be standard management for advanced radiocarpal arthritis.