Barriers to Enrollment in Post-Stroke Brain Stimulation in a Racially and Ethnically Diverse Population

Barriers to Enrollment in a Post-Stroke Neuromodulation and Walking Study: Implications for Recruiting Women

BACKGROUND

Women have a higher risk of stroke and related disability than men but are underrepresented in stroke clinical trials. Identifying modifiable recruitment and enrollment barriers for women can improve study generalizability, statistical power, and resource utilization.

OBJECTIVE

In a post-stroke neuromodulation study, we determined the impact of sex on the occurrence of exclusion criteria and compared the sex distribution of screened and enrolled individuals with a broader stroke-affected population.

METHODS

A total of 335 individuals with chronic stroke were screened for a study examining how neuromodulation and high-intensity treadmill training affect walking speed and corticomotor excitability. Demographics and exclusions were retrospectively gathered as a secondary dataset. Exclusion criteria consisted of 6 categories (not target population, unable to do treadmill protocol, unable to do non-invasive brain stimulation, insufficient ankle motion and disinterest, and cognitive impairment). Incidence of each exclusion criterion was compared between women and men. The sex distribution was compared to a dataset from Chicago primary stroke centers.

RESULTS

A total of 81 individuals were enrolled and 254 were not. The percentage of women excluded was significantly greater than that of men (P = .04). No individual exclusion criterion or categories excluded women more frequently than men. Screened and enrolled individuals had a lower proportion of women and younger age than a representative stroke population (P < .001).

CONCLUSIONS

We identified exclusion criteria (ie, headaches, cognitive scores, and age) that are modifiable barriers to enrollment of women in this post-stroke neuromodulation study. Addressing underrepresentation of women in stroke research is pivotal for enhancing generalizability, achieving statistical power, and optimizing resources.

Transcranial Direct Current Stimulation for Chronic Stroke: Is Neuroimaging the Answer to the Next Leap Forward?

During rehabilitation, a large proportion of stroke patients either plateau or begin to lose motor skills. By priming the motor system, transcranial direct current stimulation (tDCS) is a promising clinical adjunct that could augment the gains acquired during therapy sessions. However, the extent to which patients show improvements following tDCS is highly variable. This variability may be due to heterogeneity in regions of cortical infarct, descending motor tract injury, and/or connectivity changes, all factors that require neuroimaging for precise quantification and that affect the actual amount and location of current delivery. If the relationship between these factors and tDCS efficacy were clarified, recovery from stroke using tDCS might be become more predictable. This review provides a comprehensive summary and timeline of the development of tDCS for stroke from the viewpoint of neuroimaging. Both animal and human studies that have explored detailed aspects of anatomy, connectivity, and brain activation dynamics relevant to tDCS are discussed. Selected computational works are also included to demonstrate how sophisticated strategies for reducing variable effects of tDCS, including electric field modeling, are moving the field ever closer towards the goal of personalizing tDCS for each individual. Finally, larger and more comprehensive randomized controlled trials involving tDCS for chronic stroke recovery are underway that likely will shed light on how specific tDCS parameters, such as dose, affect stroke outcomes. The success of these collective efforts will determine whether tDCS for chronic stroke gains regulatory approval and becomes clinical practice in the future.