fNIRS reveals comparable reductions in cortical hyperconnectivity following once-daily and twice-daily rTMS in poststroke aphasia.

Abstract

In clinical practice, there is a common assumption that more frequent intervention yields better outcomes for patients with post-stroke aphasia (PSA). This study investigated this by comparing the efficacy of once-daily versus twice-daily low-frequency repetitive transcranial magnetic stimulation (rTMS). In this non-randomized trial, 40 PSA patients self-selected into once-daily (n = 20) or twice-daily (n = 20) 1 Hz rTMS groups targeting the right Broca's area for three weeks, alongside 26 healthy controls. Functional near-infrared spectroscopy (fNIRS) assessed oxygenated hemoglobin-based functional connectivity (FC) during a verbal fluency task pre- and post-intervention. Data were analyzed using repeated-measures ANOVA. Pre-intervention, PSA patients exhibited maladaptive cortical hyperconnectivity. Following rTMS, both groups showed comparable improvement in aphasia quotient scores, with no significant between-group differences. Analysis of fNIRS data showed that both once-daily and twice-daily rTMS regimens led to a clear reduction in the count of strong FC edges, accompanied by an overall decrease in global mean FC following intervention. Notably, reductions in global mean FC were more pronounced in the twice-daily group, whereas only modest changes were observed following once-daily stimulation. Overall, both low-frequency rTMS regimens effectively attenuated maladaptive cortical hyperconnectivity in poststroke aphasia, supporting their role in network normalization. Importantly, the absence of a clear advantage for twice-daily stimulation challenges the "more is better" paradigm and highlights the potential value of individualized and cost-effective treatment strategies.