Neurophysiological assessment of stroke recovery after repetitive transcranial magnetic stimulation

Assessing the correlation between sensorimotor evoked potential and cognitive impairment in post-stroke patients.

BACKGROUND Stroke is a leading cause of death and disability worldwide, with 35-80% of survivors developing cognitive impairment that affects quality of life. Current diagnostic tools are limited, highlighting the need for objective, cost-effective biomarkers for post-stroke cognitive impairment (PSCI). AIM To investigate the relationship between PSCI severity and sensorimotor evoked potentials, compare interhemispheric sensorimotor cortex excitability, and assess the utility of these potentials for PSCI screening. SUBJECTS AND METHODS Twenty-two stroke patients underwent neuropsychological and clinical evaluations at 3-6 months post-stroke, with testing performed within 7±3 days of the scheduled date. Patients were divided into mild cognitive impairment (MCI) and dementia groups. Motor evoked potentials (MEP) elicited by single-pulse transcranial magnetic stimulation assessed primary motor cortex excitability, while somatosensory evoked potentials (SEP) from median nerve stimulation evaluated primary somatosensory cortex excitability. RESULTS MEP absence showed a dose-dependent relationship with cognitive severity (Kendall's tau-b = -0.467, p = 0.029); 80% of MEP-absent patients had dementia versus 20% of MEP-present cases. In hemispheric analysis, affected hemispheres displayed elevated the resting motor threshold (RMT) (p < 0.001) and prolonged SEP N20 latency (p < 0.05), while unaffected hemispheres showed increased RMT in the MCI-with-MEP and dementia-without-MEP groups (p < 0.05), with reduced amplitude in dementia-with-MEP patients (p < 0.01). No linear SEP-cognition relationship emerged. CONCLUSIONS PSCI severity correlates with MEP presence/absence, not SEP measures. Notably, the excitability of the unaffected motor cortex progressively declines with worsening cognition. Although MEP shows promise as a biomarker for cognitive impairment assessment, longitudinal validation is needed to confirm its predictive utility.

Clinical and neurophysiological determinants of response to contralesional low-frequency repetitive transcranial magnetic stimulation after stroke: A systematic review and meta-analysis

Background: Low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) over the contralesional primary motor cortex is widely used for post-stroke upper-limb rehabilitation, but treatment response varies substantially. This systematic review and meta-analysis aimed to quantify the efficacy of contralesional LF-rTMS and to examine whether baseline motor impairment severity and corticospinal tract (CST) integrity modify treatment effects. Methods: We searched seven databases from inception to July 2026 for randomized controlled trials of contralesional LF-rTMS ([≤]1 Hz) versus sham after stroke, with comparable rehabilitation in both arms. The primary outcome was the change in Fugl-Meyer Assessment for the upper extremity (FMA-UE) scores. Random-effects meta-analysis used restricted maximum likelihood estimation with Knapp-Hartung adjustment. Effect modification was examined through meta-regression and biomarker-stratified analyses, and neurophysiological outcomes were also synthesized. Results: Thirty trials (33 comparisons, 1,668 participants) were included. LF-rTMS produced greater FMA-UE improvement than sham (mean difference 4.11 points, 95% CI 2.83-5.39; Hedges g 0.64, 95% CI 0.45-0.84), with substantial heterogeneity. Baseline severity did not significantly modify the effect in continuous meta-regression. However, exploratory within-trial biomarker-stratified analyses suggested larger effects in participants with preserved CST integrity or positive motor-evoked potential (MEP) status. LF-rTMS also shortened MEP latency and central motor conduction time, but these measures could not be validated as surrogate endpoints. Conclusions: Contralesional LF-rTMS provides a statistically significant but modest improvement in post-stroke upper-limb motor recovery. Baseline clinical severity alone may not identify responders, whereas CST integrity is an exploratory, hypothesis-generating candidate biomarker. It requires confirmation in adequately powered biomarker-stratified trials before it can inform clinical decisions. Trial Registration The study was registered with the International Prospective Register of Systematic Reviews (PROSPERO: CRD420261441561).

Neurophysiological effects of transcranial alternating current stimulation combined with multidisciplinary rehabilitation in Parkinson’s disease

Introduction Motor impairment in Parkinson’s disease (PD) often becomes inadequately controlled as the disease progresses. Rehabilitation therapy combined with noninvasive neuromodulation has shown benefits, yet the neural mechanisms underlying this remain unclear. This study aimed to identify neurophysiological and brain network features associated with motor improvement following high-intensity transcranial alternating current stimulation (Hi-tACS) combined with multidisciplinary intensive rehabilitation therapy (MIRT). Methods This secondary analysis was based on a randomized controlled trial (ChiCTR2300071969). Thirty patients receiving Hi-tACS combined with MIRT were included. Responders were defined as patients achieving a minimal clinically important difference improvement greater than 3.25 points on the Unified Parkinson’s Disease Rating Scale part III. Electroencephalographic spectral analysis, resting-state functional connectivity, and dynamic brain states assessed using hidden Markov modeling were performed. Partial correlation analyses were conducted for group-differentiating measures, controlling for age and disease duration. Results Compared with non-responders, responders showed increased temporal high beta frequencies relative power (95%CI 0.85(0.01–1.66), P = 0.047), reduced connectivity between the default mode and sensorimotor networks (95%CI -0.89(-1.71–0.05), P = 0.038), and decreased fractional occupancy of state 3 (95%CI 0.03(0.00–0.28), P = 0.033) and 6 (95%CI 0.02(0.00–0.35), P = 0.038). After Bonferroni correction, only changes in temporal high beta frequencies relative power were negatively correlated with changes in total UPDRS part III scores (R = -0.59, PBON = 0.012) and rigidity subscores (R = -0.74, PBON < 0.001). Discussion These results suggest that motor improvement following combined Hi-tACS and MIRT in PD patients is associated with alterations in brain oscillations and network connectivity, particularly in high-beta frequencies. The findings contribute to understanding the neural mechanisms underlying rehabilitation and neuromodulation in PD. Future studies should investigate the long-term effects of this intervention and its applicability in larger, more diverse populations. Moreover, exploring additional biomarkers may help identify individuals who are most likely to respond to this treatment. Clinical Trial Registration https://www.chictr.org.cn, identifer ChiCTR2300071969.

Brain age is associated with cognitive improvement following repetitive transcranial magnetic stimulation in late-life depression.

BACKGROUND Late-life depression (LLD) is commonly accompanied by cognitive impairment and poor response to first-line antidepressants. Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for treatment-resistant LLD, yet neurobiological predictors of cognitive and clinical outcomes remain unclear. Brain aging, quantified via magnetic resonance imaging (MRI)-derived centile scores from normative brain charts, may capture individual variability in neurostructural aging relevant to rTMS treatment response. METHODS We examined relationships between centile scores, cognition, and antidepressant outcomes in older adults with LLD (n=112) and healthy controls (HC; n=41) who participated in a noninferiority clinical trial of bilateral dorsolateral prefrontal cortex (DLPFC) rTMS versus theta burst stimulation. Structural MRI was obtained before and after treatment. Centile scores leveraging cortical and subcortical tissue volumes were generated using BrainChart.io. Cognitive outcomes were assessed using standardized neuropsychological measures, including verbal learning and executive function. RESULTS Baseline centile scores did not differ between the LLD cohort and HCs and were unrelated to depression severity or antidepressant response. However, participants in a cognitively-diminished LLD subtype exhibited significantly lower centile scores driven by reduced white-matter volume. Across LLD participants, higher baseline centile scores predicted greater improvement in verbal learning following rTMS, but not global cognition or executive function, independent of antidepressant response. Centile scores remained stable post-treatment. CONCLUSIONS Brain age measures reflect cognitive, but not antidepressant, outcomes following rTMS in LLD. Structural-MRI based centile scores may serve as biomarkers of cognitive function and predictors of rTMS-related cognitive improvement in individuals with LLD.

Thalamic tFUS for Post-Stroke Motor Recovery: A Pilot Multimodal Neurobehavioral Study

Brain-computer interface training for motor recovery after stroke.

Overall, the certainty of evidence was low to very low, downgraded primarily for these risk of bias concerns, severe imprecision (due to small sample sizes), and potential publication bias.