Transcranial Direct Current Stimulation on Cortical Plasticity in Patients With Anti-NMDA Receptor Encephalitis

Study Overview
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Brief Summary
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Patients suffering from anti-NMDA receptor encephalitis show impaired NMDA-receptor dependent neuronal transmission. Furthermore, they often have cognitive deficits of different magnitude. Impaired neuronal signaling of NMDA-receptors very likely result in decreased cortical synaptic plasticity. Thus, this represents one major reason of cognitive deficits. Synaptic plasticity can be assessed in humans via the non-invasive technique of transcranial magnetic stimulation (TMS). The current study aims to investigate whether learning ability and also cortical plasticity can be changed by applying sessions of transcranial direct current stimulation (tDCS). Therefore, we are recruiting 10 to 15 patients suffering from anti-NMDA receptor encephalitis as well as healthy controls in order to compare tDCS effects. Learning ability is assessed by motor sequence tasks, whereas cortical plasticity is measured via TMS. tDCS is a novel non-invasive technique allowing induction of changes in cerebral excitability level and also cortical plasticity. Previous studies showed positive outcome of anodal stimulation on learning tasks. Especially motor learning seems to be an important target for tDCS treatment since it showed best results for both post-stroke patients and healthy subjects. Multiple sessions of tDCS are inducing long-term effects and improved learning function, which were present three months after stimulation. In this study we hope to reveals new insights into the pathomechanisms of impaired cognitive and learning abilities in patients having anti-NMDA receptor encephalitis. Moreover, we evaluate whether tDCS is an effective treatment for patients with cognitive and learning deficits.

Conditions
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Anti-NMDA Receptor Encephalitis

Intervention / Treatment
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* Device: tDCS
* Device: Sham Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients suffering from anti-NMDA receptor encephalitis healthy (control) subjects Exclusion Criteria: Any metal inside the body/head, e.g. clips, pace maker, medical pumps, cochlear implant etc. Traumatic brain injury Stroke Cerebral tumor Pregnancy untreated severe internal or psychiatric diseases

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: tDCS<br>Transcranial direct current stimulation | Device: tDCS<br>* Transcranial direct current stimulation involves the application of weak electric currents to the brain.<br>|
| Sham Comparator: sham stimulation<br>sham stimulation | Device: Sham Stimulation<br>* no electrical stimulation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| neurophysiological measurements using TMS | TMS protocoll (a paired associative stimulation) is applied after tDCS or sham stimulation | 1 week | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| performance in a motor task | performance in a motor task is compared after a tDCS or sham stimulation | 1 week |