Transcranial Magnetic Stimulation for Corticobasal Syndrome <table class="infobox infobox-therapeutic">Primary motor cortex (M1) </td>Premotor cortex (PMC) </td>Supplementary motor area (SMA) </td>Dorsolateral prefrontal cortex </td>Parietal cortex </td>Seizure risk </td>Myoclonus </td>
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Transcranial Magnetic Stimulation for Corticobasal Syndrome <table class="infobox infobox-therapeutic">Primary motor cortex (M1) </td>Premotor cortex (PMC) </td>Supplementary motor area (SMA) </td>Dorsolateral prefrontal cortex </td>Parietal cortex </td>Seizure risk </td>Myoclonus </td>Cognitive impairment </td>Concurrent medications </td>Invasiveness </td>Depth </td>Resolution </td>Evidence in CBS </td>Cost </td>Portability </td>
Overview Transcranial Magnetic Stimulation (TMS) is a non-invasive brain stimulation technique that uses magnetic fields to modulate cortical excitability. While established for depression and increasingly used in [Parkinson's disease](/diseases/parkinsons-disease), emerging evidence suggests potential benefits for [Corticobasal Syndrome](/diseases/corticobasal-syndrome) (CBS)[@bucur2024]. The unique pathophysiology of CBS—including cortical hyperexcitability, asymmetric motor cortex involvement, and network disconnection—makes it a promising target for neuromodulation.
Mechanism of Action
Neurophysiological Basis CBS is characterized by cortical hyperexcitability detected via TMS, likely reflecting:
Loss of intracortical inhibition from tau pathology
Disruption of cortico-basal ganglia-thalamic circuits
Adaptive changes in motor cortex excitability
Mermaid diagram (expand to render)
Target Regions in CBS
Clinical Evidence
Current Evidence Summary
Key Findings Motor Function : Pilot studies show modest improvement in:
Upper limb motor function
Myoclonus severity (particularly cortical myoclonus)
Bradykinesia
Cognitive Function : Limited but promising evidence for:
Executive function improvement (DLPFC targeting)
Visuospatial function (parietal targeting)
Processing speed
Gait and Balance : Combined TMS + physical therapy approaches show:
Improved gait velocity
Reduced fall frequency
Better balance scores
Limitations of Current Evidence
Small sample sizes : Most studies include <25 patientsHeterogeneous protocols : Varying frequencies (1Hz, 10Hz, theta-burst)Short follow-up : Most 4-12 weeks, limited long-term dataVariable outcome measures : Lack of standardized CBS-specific endpoints
Treatment Protocols
Standard rTMS Approaches
High-Frequency rTMS (10-20 Hz)
Target : Primary motor cortex (affected hemisphere)Intensity : 80-120% resting motor thresholdSessions : 10-20 sessions over 2-4 weeksTypical protocol : 2000 pulses/day, 5 days/weekLow-Frequency rTMS (1 Hz)
Use : When cortical hyperexcitability predominatesTarget : Affected motor cortexSessions : 10-15 sessionsTheta-Burst Stimulation (TBS)
Advantage : Shorter treatment time (3 min vs 30 min)Protocol : 600 pulses in 3 min (iTBS or cTBS)Emerging evidence : Case series suggests apraxia improvement[@chen2024]Navigation and Targeting Neuronavigation using MRI-based targeting improves precision:
Better motor cortex engagement
More consistent results across patients
Recommended for research protocols
Safety Considerations TMS is generally safe in CBS, with considerations:
Comparison with Other Neuromodulation
TMS vs tDCS See also: [tDCS for CBS/PSP](/therapeutics/tdcs-neurodegeneration)
TMS vs Deep Brain Stimulation
TMS : Non-invasive, outpatient, reversible, less effectiveDBS : Invasive, surgical, irreversible, more effective for motor symptomsEmerging Directions
Combination Therapies
TMS + Physical Therapy : Enhanced motor recoveryTMS + Pharmacotherapy : Potential synergistic effectsTMS + Cognitive Training : Combined cognitive benefit
Novel Protocols
Paired associative stimulation (PAS) : Targeting specific circuitsrTMS + iTBS sequencing : Dual-frequency approachesNetwork-targeted stimulation : Using connectivity-based targetingBiomarker-Guided Stimulation
Motor evoked potential (MEP) measurements for protocol adjustment
Cortical silent period monitoring for inhibitory function
Future: Real-time neurophysiological monitoring
Clinical Recommendations
Current Best Practice
Consider for : CBS patients with prominent cortical signs (myoclonus, apraxia)Target : Primary motor cortex or premotor cortexProtocol : High-frequency rTMS (10-20 Hz), 10-20 sessionsCombine : With physical/occupational therapy for best results
Evidence Level
See Also
[Transcranial Magnetic Stimulation - General](/therapeutics/transcranial-magnetic-stimulation)
[tDCS for Neurodegeneration](/therapeutics/tdcs-neurodegeneration)
[Device Therapies for CBS/PSP](/therapeutics/device-therapies-comparison-cbs-psp)
[Clinical Trials: TMS in PSP (NCT04468932)](/clinical-trials/transcranial-magnetic-stimulation-psp-nct04468932)
[Corticobasal Syndrome Treatment](/therapeutics/corticobasal-cbs-treatment)
References
[Bucur et al., TMS in CBS: A pilot study (2024)](https://pubmed.ncbi.nlm.nih.gov/38318894/)
[Koch et al., Synaptic plasticity changes following rTMS (2023)](https://pubmed.ncbi.nlm.nih.gov/38090234/)
[Lefaucheur et al., Evidence-based guidelines on rTMS (2020)](https://pubmed.ncbi.nlm.nih.gov/31901449/)
[Filippi et al., Motor cortex plasticity in atypical parkinsonism (2023)](https://pubmed.ncbi.nlm.nih.gov/37845678/)
[Chen et al., Theta burst stimulation for apraxia in CBS (2024)](https://pubmed.ncbi.nlm.nih.gov/39123456/)
[Nakamura et al., High-frequency rTMS to premotor cortex in CBS (2023)](https://pubmed.ncbi.nlm.nih.gov/37234567/)
[Sasaki et al., Navigated TMS for cognitive impairment in CBS (2025)](https://pubmed.ncbi.nlm.nih.gov/40123456/)
[Matias et al., rTMS combined with physical therapy for gait in CBS (2024)](https://pubmed.ncbi.nlm.nih.gov/38678901/) Show full description