The goal of this pilot trial is to test whether scrambler therapy (ST) is an effective treatment for neuropathic pain in patients with corticobasal syndrome (CBS).

The main question it aims to answer is:

Will ST reduce pain scores by at least 33% at one month in this pilot trial, justifying further multi-center trials?

Participants will:

• be randomly assigned treatment from either transcutaneous electrical nerve stimulation (TENS) or ST for pain initially (eventually all patients will receive ST).
• have superficial electrocardiogram (ECG) electrodes placed on the dermatomes involved with pain
• obtain treatment lasting 30-40 minutes or until pain relief is obtained

Researchers will compare patient's response to pain relief with TENS and ST to determine if ST is an effective treatment for central neuropathic pain.

Pain can be a common non-motor complication of corticobasal syndrome (CBS), which is a rare debilitating parkinsonian disorder that lacks disease-modifying therapies. Pain in CBS typically increases in severity as the disease progresses and adversely impacts quality of life (including sleep and daily function). Scrambler therapy is a non-invasive electrical approach to neuromodulation that sends "nonpain" information along the existing nerve pathways to modify peripheral and central sensitization with success in randomized controlled trials treating such difficult neuropathies as spinal cord stenosis, post-herpetic neuropathy and failed back syndrome; chemotherapy induced neuropathy; and neuromyelitis optica spectrum disorder (NMOSD). To date, four patients with CBS treated empirically with ST have experienced long lasting pain relief with treatment, suggesting a novel approach to a vexing symptom.

An estimated 35-80% of patients with Parkinson disease experience pain and it is highly likely that pain is more frequent in CBS, though estimates are lacking because CBS is a rare syndrome. This pain can be related to dystonia, musculoskeletal, radicular-peripheral neuropathic, and central neuropathic pain syndromes. Similar symptoms are found in patients with CBS. Currently, there are no FDA approved disease-modifying treatments. Although treatments for pain have been helpful, ultimately adjunct therapies are needed as the disease progresses. A simple, low-cost, non-invasive available treatment to reduce the pain of CBS is sorely needed. This pilot trial will provide data on which to design a larger randomized controlled trial.

Research Hypothesis: Scrambler Therapy (ST) will reduce pain scores by at least 33% at one month in this pilot trial, justifying further multi-center trials.

Inclusion Criteria:

• men and women, ≥50 years of age or older with CBS with an average daily pain rating of > 4 out of 10, using the following question from the Brief Pain Inventory: "Please rate your pain by circling the one number that best describes your (abdominal) pain/discomfort on average over the past week. (Scale 0-10; 0= No pain, 10= Pain as bad as you can imagine)
• English speakers or English proficiency
• They must have a life expectancy > 90 days per their treating neurologist.
• The patient must be able to understand the study regimen, its requirements, risks, and discomforts, and is able and willing to sign an informed consent form.

Exclusion Criteria:

• Pregnant women, nursing women, women of childbearing potential or their sexual partners who are unwilling to employ adequate contraception (condoms, diaphragm, birth control pills, injections, intrauterine device, surgical sterilization, subcutaneous implants, abstinence, etc.). Other exclusions include the following:
• Use of an investigational agent for pain control concurrently or within the past 30 days,
• History of an allergic reaction or previous intolerance to transcutaneous electronic nerve stimulation;
• Patients with implantable drug delivery systems, e.g. Medtronic Synchromed, baclofen pumps.
• Patients with heart stents or metal implants such as pacemakers, automatic defibrillators, cochlear implants, aneurysm clips, vena cava clips and skull plates. (Metal implants for orthopedic repair, e.g. pins, clips, plates, cages, joint replacements are allowed).
• Medical exclusions include: patients with a history of myocardial infarction or ischemic heart disease within the past six months; patients with history of epilepsy, brain damage, or symptomatic brain metastases; skin conditions such as open sores that would prevent proper application of the electrodes; or other medical or other condition(s) that in the opinion of the investigators might compromise the objectives of the study.

Patients will be masked on whether they will receive scrambler therapy or TENS treatment for neuropathic pain.