This study will focus on the efficacy of treating 80 patients who have functional limitations in activity because of chronic/recurrent neck or shoulder pain.

Hypothesis 1: InterX therapy alone will have a moderate effect to reduce pain during weeks 1-2.

Hypothesis 2: Functional gains will be greater in patients receiving InterX therapy compared to those who received placebo treatment.

Hypothesis 3: Chronic neck and shoulder pain is more prevalent in patients who exhibit radiographic evidence of degenerative spondylosis/arthrosis of the cervical spine.

Evaluation of subjects will be conducted at baseline (interval 0) and at 2, 4, 6 and 12 week time periods. At 26 weeks, the patient will be contacted to obtain follow-up questionnaires on pain and function. After informed consent, participants will be randomly assigned to a treatment group and a sham group using the InterX5002, hand held electrical stimulation unit. Treatment will be administered three times per week for six weeks.

During the interval of weeks 1-2 patients will have either the InterX treatment/sham alone. Weeks 3-4 will advance the patient adding a standardized rehabilitation exercise program typical for chronic neck patients. During weeks 5-6, the patient will be scheduled for treatment and will use a self-administered InterX treatment ("home" Flex) unit mimicking home care but accounting for compliance issues through attendance being monitored.

Baseline and follow-up assessments will consist of pain scores, NDI, neck fatigue testing, shoulder and arm reach tasks and walking on a treadmill at 2 MPH for 5 minutes (Neck-walk Index, NWI). Neck fatigue testing will consist of prone positioning and extensor muscle exertion against resistance to tolerance at 60% MVC. Myoelectric sensors will be taped to the skin to record muscle activity during fatigue and reach task testing. Electromagnetic sensors will be taped to a swimmers cap worn by the patient and on the skin at T1 over the spine at the shoulder level and S1 at the pelvis during the walk on the treadmill and on the shoulder and arm during reach testing.

Venipuncture will be performed at the evaluation intervals to collect blood samples for quantifying circulating inflammatory cytokines.

Analysis will focus on change in pain scores and inflammatory cytokines over the first two weeks for Hypothesis H1. Primary functional outcomes including neck fatigue and progression through neck rehabilitation exercise will be tested for Hypothesis2. The third hypothesis will be tested in two ways. First, quantification of degenerative changes (e.g.disc narrowing & osteophyte formation) on x-ray (AP & Lat screening views) will be contrasted to incidence in the published literature. Second, pain levels at baseline will be stratified into quartiles and compared to quantitative tally of degenerative changes. This data will serve as a basis for determining whether future studies using degenerative change criteria are warranted. Myoelectric activity, fatigue and head-pelvic position data will be used descriptively to assess functional differences from baseline to completion of treatment.

Inclusion Criteria:

• males or females
• ages 18-65
• chronic or recurrent neck or shoulder pain
• pain of at least 3 months duration
• willing to sign consent form
• able/willing to comply with treatment schedule

Exclusion Criteria:

• age over 65 years
• clinically significant herniated disc
• spinal fracture
• previous electrical stimulation treatment for this episode
• recent cervical spine or shoulder surgery
• implanted instrumentation/prostheses
• epilepsy
• pregnancy
• recent (3 months) chemotherapy/radiotherapy
• phlebitis
• cortisone use (30 days)
• hypersensitivity to tape used with EMG