Systematic review on the association between brain-related measures and upper limb movement characteristics after stroke

 Useless! 'Associations' DO NOTHING towards getting survivors recovered. When you have a stroke you'll understand the shitworthy research you were doing and come to the same conclusion I have. 

And Steven C. Cramer is a rock star in stroke research.

Systematic review on the association between brain-related measures and upper limb movement characteristics after stroke

• Anne Schwarz,
• Min-Keun Song,
• Ming Wu,
• Shivani Sakthi,
• Maeve Settle,
• Eden Farahmand,
• Rachel Wing,
• Matthew Hansen,
• Janne Marieke Veerbeek &
• Steven C. Cramer 

We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.

Abstract

Background

Upper limb (UL) movements are highly diverse, as are movement deficits following stroke. The relationship that stroke pathology has with UL impairments and their recovery has been studied with an increasingly complex array of neuroimaging and neurophysiology tools. This systematic review summarizes evidence on brain-related measures and UL movement in subjects with stroke.

Methods

Bibliographic databases were systematically searched for combinations of ‘brain function’ and ‘kinematics/ kinetics/ muscle activity’ and ‘stroke’ and ‘upper limb’. Studies were included if both brain and UL movement measures were assessed in at least 10 subjects. Each study was evaluated for risk of bias (adapted QUADAS-2 tool). Information on assessments for brain and UL measures, their associations, and experimental tasks was extracted, summarized, and synthesized. This study was registered on PROSPERO (CRD42025637373).

Results

A total of 220 studies were included that reported 288 experimental tasks across 4'954 subjects with stroke (mean 59.7 years). Transcranial magnetic stimulation, functional magnetic resonance imaging (fMRI), and electroencephalography, commonly combined with grip force sensors and motion sensor- or camera-based systems, were the most frequently used methodologies. Overall, 92 brain-related and 201 UL metrics were assessed. Risk of bias was low-to-moderate. Structural brain measures revealed associations between corticospinal tract integrity and greater grip strength, as well as kinematic differences between left- and right-hemisphere stroke locations. For functional brain measures, increased activation of ipsilesional motor areas during fMRI was associated with improved smoothness. In addition, studies reported reduced activation intensity and excitability after stroke, alongside task-related recruitment of additional brain areas.

Discussion

This review summarizes a large and heterogeneous body of research reflecting substantial methodological and technological advances in the assessment of brain and UL movement measures after stroke. The current findings support the relevance and utility of combining brain-based and UL metrics to identify meaningful associations between neurological injury, brain function, and behavioral outcomes after stroke and thereby provide an improved understanding of movement after stroke.