Neurophysiologic Signatures of Trigeminal Neuralgia Pain
Condition: Trigeminal Neuralgia (TN)
MeSH terms: Trigeminal Neuralgia; Neuralgia
Study type: Interventional

Summary: 
      Trigeminal neuralgia (TN) is an idiopathic pain disorder that is characterized by episodic
      attacks of intense facial pain, described as paroxysms of stabbing, electric, or explosive
      pain, and lasting for a few seconds or longer, often producing a tic-like facial movement,
      and can occur up to hundreds of times per day. This pain is known to be one of the worst pain
      conditions that a patient can suffer and has been called the "suicide disease". Given the
      severity of this disorder, determining the cause becomes essential for finding a cure. This
      project will study the cause of TN using a translational approach, which means the research
      project will be completed in both humans and animals. The investigators hypothesize that
      there are specific areas of the brain and spinal cord that will provide a "signature" center
      of activity. The study team will use state of the art magnetic resonance imaging (MRI)
      machines and other non-invasive brain activity measurements, including electroencephalography
      (EEG) to locate these centers in people with TN before and after their pain has started.
      Recent studies have investigated the effects of transcranial electrical stimulation (tES) for
      pain control. Transcranial electrical stimulation (tES) includes transcranial direct current
      stimulation (tDCS) and transcranial alternating current stimulation (tACS). This approach is
      important because identifying similar regions neural activity will allow for us to study
      novel therapies in search of the cure for TN and this study has thus both basic and clinical
      neuroscience significance.
    

Detailed description: 
      Trigeminal neuralgia (TN) is an extremely painful and highly disabling orofacial pain
      disorder, often referred to as the "suicide disease," for which presently available therapies
      are largely ineffective or inadequate. Both the unpredictable response to treatment and
      variability in long-term clinical outcomes in TN strongly suggest that a range of peripheral
      and central mechanisms remain to be understood. The long-term goal is to identify the
      mechanisms involved in the initiation and progression of TN, and uncover rational targets for
      the safe and effective treatment of TN. The objective of this application is to explore the
      use of multimodal neuroimaging and neurophysiologic techniques in defining neural signatures
      of the disease. Additionally, the study team wants to evaluate the efficacy of transcranial
      electrical stimulation on relieving pain. The rationale for the proposed research is that
      identification of signature peripheral and central activation sites will allow for
      individualized treatment strategies for TN patients.

      To modulate brain activities the investigators will use transcranial electrical stimulation
      (tES). tES is an emerging neuromodulation technique that can be noninvasively and safely
      applied in humans. tES can help better understand the causal roles of brain networks and
      brain activities and has shown efficacy in improving pain. tES has two main variations:
      transcranial direct current stimulation (tDCS) and transcranial alternating current
      stimulation (tACS). The former applies a weak direct current to the scalp whereas the latter
      applies a weak sinusoidal current to the scalp. tDCS can modulate the excitability of tissues
      under the stimulating electrodes. tACS is particularly suited for interacting with various
      oscillatory activities in the brain. tES has been used to study normal brain function and
      treat neurological and pain disorders as well. There is demonstrated efficacy in improvement
      of pain in subjects suffering from fibromyalgia and neuropathic pain. The study team will use
      different tDCS/tACS montages targeting different brain regions and observe behavior and
      neuronal activities. The current strength will be within 1mA or 2mA which has been shown to
      be safe and effective.
    

Intervention name(s): transcranial electrical brain stimulation
Intervention type(s): Procedure
Intervention description(s): Pain ratings will be recorded before and after transcranial brain electrical stimulation procedures using a Visual Analog Scale (VAS).
Other intervention name(s): tES
Intervention model: Single Group Assignment
Intervention model description: The investigators will use of transcranial electrical stimulation (tES) to evaluate pain in patients with Trigeminal Neuralgia (TN).
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: transcranial electrical stimulation (tES)