Brain as a Therapeutic and Research Target in Trigeminal Neuropathic Pain

University of Michigan

Status: Completed

Conditions: Trigeminal Neuropathic Pain

Treatments: Other: sham tDCS (prior to real tDCS); Procedure: MRI; Procedure: transcranial direct current stimulation (tDCS); Procedure: PET Scans

Study type: Interventional

Funder types: Other

Identifiers

NCT03003715

HUM00024607

Details and patient eligibility

About

The main goal of this study to integrate techniques producing images of the brain (also called neuroimaging techniques) with non-invasive brain stimulation to investigate factors that may be associated with chronic pain in patients with Trigeminal Neuropathic Pain (TNP).

Full description

Trigeminal neuropathic pain (TNP) disorders, such as classical trigeminal and post-surgical neuralgia, are debilitating chronic conditions with pain that is either spontaneous or that can be intensely evoked by light touch to the facial skin. Although neuroimaging techniques have provided insights into some brain mechanisms of experimental trigeminal pain in humans (DaSilva et al., 2002; Borsook et al., 2003), it is not well understood how structural and molecular mechanisms are affected during the course of TNP, and how they can be safely modulated for therapeutic and research purposes. Understanding these processes is crucial to determine the structures engaged in the development and persistence of TNP.

We will test the hypothesis that chronicity of TNP is sustained by changes at cellular and molecular levels in neural circuits associated with pain perception and modulation, rather than by the initial peripheral etiology, and that this dysfunction can be safely targeted and modulated as a therapeutic approach by transcranial direct current stimulation (tDCS). To achieve this goal we will use a neuroimaging technique, PET, employing a mathematical model that permits the quantification of opioid receptor availability in vivo.

Enrollment: 13 patients

Sex: All

Ages: 18 to 65 years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion criteria

Patient Inclusion Criteria:

• Daily chronic TNP for at least 6 months not adequately controlled by pervious medicine therapies;
• minimal average baseline pain score of 4 (moderate to severe) in the visual analogue scale (VAS);
• unilateral pain
• orofacial allodynic region to mechanical (light touch or palpation) or thermal stimulation (head or cold);

Patient Exclusion Criteria:

• pregnancy or planning to become pregnant
• local pathology (e.g. orofacial lesion)
• history of systemic disorders (e.g. MS)
• history of other chronic pain disorder (e.g. back pain)
• recent orofacial surgery or trauma (< 6 months)
• history of central origin disorders (e.g. stroke)

Trial design

Primary purpose: Treatment

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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13 participants in 2 patient groups

Refractory Trigeminal Neurpathic Pain (TNP) Patients

Experimental group

Description:

All patients receive QST prior to PET scan used to obtain baseline measures, then placebo tDCS, followed by QST and Active tDCS, over the course of a 90 minute PET scan; QST is used again to take final measurements 30 minutes later.

Treatment:

Procedure: transcranial direct current stimulation (tDCS)

Procedure: MRI

Procedure: PET Scans

Other: sham tDCS (prior to real tDCS)

Healthy volunteers

Experimental group

Description:

All volunteers receive QST prior to PET scan used to obtain baseline measures, then placebo tDCS, followed by QST and Active tDCS, over the course of a 90 minute PET scan; QST is used again to take final measurements 30 minutes later.

Treatment:

Procedure: transcranial direct current stimulation (tDCS)

Procedure: MRI

Procedure: PET Scans

Other: sham tDCS (prior to real tDCS)