Serial treatments of primed low-frequency rTMS in stroke: Characteristics of responders vs. nonresponders

Abstract

Purpose This study analyzed the characteristics of responders vs. nonresponders in people with stroke receiving a novel form of repetitive transcranial magnetic stimulation (rTMS) to improve hand function. Methods Twelve people with stroke received five treatments of 6-Hz primed low-frequency rTMS to the contralesional primary motor area. We compared demographic factors, clinical features, and the ipsilesional/contralesional volume ratio of selected brain regions in those who improved hand performance (N = 7) on the single-hand component of the Test Évaluant la performance des Membres supérieurs des Personnes Âgées (TEMPA) and those who showed no improvement (N = 5). Results Responders showed significantly greater baseline paretic hand function on the TEMPA, greater preservation volume of the ipsilesional posterior limb of the internal capsule (PLIC), and lower scores (i.e. less depression) on the Beck Depression Inventory than nonresponders. There were no differences in age, sex, stroke duration, paretic side, stroke hemisphere, baseline resting motor threshold for ipsilesional primary motor area (M1), NIH Stroke Scale, Upper Extremity Fugl-Meyer, Mini-Mental State Examination, or preservation volume of M1, primary somatosensory area, premotor cortex, or supplementary motor area. Conclusion Our results support that preserved PLIC volume is an important influential factor affecting responsiveness to rTMS.

Impact of 5‐Hz rTMS over the primary sensory cortex is related to white matter volume in individuals with chronic stroke

“…In this case, assessing regional WM volume may provide an alternative approach to assess cortical WM integrity. Interestingly, it was recently reported that after stroke, the amount of preserved volume of the ipsilesional posterior limb of the internal capsule is an influential factor when differentiating between rTMS responders and non‐responders (Carey et al ., ). This reinforces the value of segmented WM volume analysis, and further emphasizes the importance of WM preservation for predicting response to rTMS.…”

A Review of Transcranial Magnetic Stimulation and Multimodal Neuroimaging to Characterize Post-Stroke Neuroplasticity

“…DW-MRI has been touted as a promising tool for rehabilitation planning and prognosis after stroke ( 31 ), and may predict neural changes after motor learning. Importantly, preliminary studies have demonstrated that the integrity of CST ( 24 , 34 ) and CC ( 35 ) influences the efficacy of rTMS, suggesting that DW-MRI can provide valuable information when selecting rTMS protocols and predicting the efficacy of an intervention.…”

“…Since rTMS is known to modulate cortical excitability in local and remote regions to the areas stimulated, it has been suggested to be a viable therapeutic approach to aid in the recovery of motor function after stroke ( 207 ), yet there is accumulating evidence that the response to rTMS is inconsistent and variable ( 34 , 193 , 194 ). When targeting stimulation over M1, rTMS has been delivered in isolation ( 34 , 208 – 210 ) and in combination with rehabilitation training ( 193 , 194 , 211 , 212 ) in individuals with stroke.…”

Effects of repetitive transcranial magnetic stimulation on motor recovery and motor cortex excitability in patients with stroke: a randomized controlled trial

“…Numerous neuroimaging studies have identified that motor recovery is related to neural plasticity and cortical reorganization . In recent years, non‐invasive brain stimulation techniques, such as repetitive transcranial magnetic stimulation (rTMS) in particular, have been used to promote functional recovery of stroke patients by modulating cortical excitability and inducing neural plasticity . According to the interhemispheric inhibition model , ‘overactive’ motor areas of the unaffected hemisphere may exhibit abnormally high interhemispheric inhibition to the primary motor cortex (M1) of the affected hemisphere, and thereby weaken motor function and hamper the recovery of the affected extremity.…”