Transcranial Stimulation (tDCS) For the Treatment of Neuropathic Facial Pain

This is a pilot study designed to collect preliminary data on safety and efficacy of
transcranial direct current stimulation (tDCS)to relieve pain in subjects with neuropathic
facial pain,and to compare two pain-treatment tDCS modalities: inhibitory tDCS stimulation
over the somatosensory cortex and excitatory tDCS over the motor cortex.

Inclusion Criteria:

- Spontaneous facial neuropathic pain due to any of following:

1. Trigeminal neuralgia, type 1, (TN1): facial pain of spontaneous onset with
predominantly episodic pain.

2. Trigeminal neuralgia, type 2, (TN2): facial pain of spontaneous onset with
predominantly constant pain.

3. Trigeminal neuropathic pain, (TNP): facial pain resulting from unintentional
injury to the trigeminal system from facial trauma, oral surgery, ear, nose and
throat (ENT) surgery, root injury from posterior fossa or skull base surgery,
stroke, etc.

4. Trigeminal deafferentation pain, (TDP): facial pain in a region of trigeminal
numbness resulting from intentional injury to the trigeminal system from
neurectomy, gangliolysis, rhizotomy, nucleotomy, tractotomy, or other
denervating procedures.

5. Symptomatic trigeminal neuralgia, (STN): facial pain resulting from multiple
sclerosis.

e) Postherpetic neuralgia, (PHN): facial pain resulting from trigeminal Herpes zoster
(shingles) outbreak in the trigeminal distribution.

- Pain intensity score for "worst pain in the last 24 hours" >4 on a numeric scale 0-10
at the time of enrollment and before the first stimulation of each treatment block.

- Pain intensity score for "pain right now" >4 on a numeric scale 0-10 before the first
stimulation of each block of treatment.

Exclusion Criteria:

- Uncontrolled hypertension, uncontrolled diabetes, uncontrolled cardiovascular disease

- Other painful conditions than neuropathic facial pain, that are not related to and
can't be distinguished from the neuropathic facial pain

- Pregnancy

- Implanted neurostimulation devices (e.g. a spinal cord stimulator, a deep brain
stimulator, etc)

- Active illegal drug/alcohol abuse

- Unable to follow directions or complete tools in English.