Local Effects of Acupuncture and Nerve Conduction Studies

The purpose of this study is to measure the local effects of acupuncture on the median and ulnar nerves in patients with median neuropathy at the wrist (carpal tunnel syndrome), using nerve conduction studies (NCS) and quantitative sensory testing (QST) as outcomes. Our secondary aim is to compare acupuncture's effect on the functioning of a diseased nerve (median nerve in CTS) to its effect on a healthy nerve (ulnar). Additionally, we aim to compare the local, nerve-specific effect of manual acupuncture to that of low-frequency electroacupuncture and of high-frequency electroacupuncture.

In a mechanistic study of acupuncture, 60 subjects with carpal tunnel syndrome (CTS) will be randomized to manual acupuncture (MA), low-frequency electroacupuncture (LF-EA) and high-frequency electroacupuncture (HF-EA) groups. Baseline measurements will consist of QST (vibration and cold detection thresholds), as well as NCS of both median and ulnar nerves. Then, each group will undergo acupuncture to the median nerve (Pericardium channel points) and to the ulnar nerve (Heart channel points), one week apart, order counterbalanced, followed by post-acupuncture NCS and QST measurements in both nerves' territories.

Inclusion criteria

• Presence of mild-moderate sensorimotor or sensory median neuropathy, established by pre-existing NCS/EMG study AND
• Baseline NCS study within the past 2 years, consistent with mild-moderate median entrapment neuropathy (CTS) defined as meeting any of the 3 conditions below:

• Prolonged distal Median sensory AND/OR motor latency
• Reduced Median sensory nerve action potentials (SNAP) amplitude by no more than 50%
• Amplitude of the compound muscle action potential (CMAP) recorded from APB > 50% of normal
• Presence of neuropathy symptoms consistent with CTS for at least 3 months

Exclusion criteria

Conditions in which acupuncture/electroacupuncture may be contraindicated:

• Coagulopathy/ Current anti-coagulation treatment
• Epilepsy
• History of CAD or pacemaker insertion
• Pregnancy
• Presence of any skin condition in the arm, such as dermatitis, bruises, weeping skin, skin lesions, infected skin, or necrotic skin.

Conditions in which QST testing may be contraindicated:

• Significant cognitive impairment such as diagnosis of Alzheimer's disease or Mental Retardation or any other condition interfering with alertness, attention and ability to participate in QST
• Hospitalization for anxiety or depression in the past 3 months
• Current psychiatric diagnoses (other than anxiety or depression)
• Illicit drug use in the past month
• Current EtOH abuse (> 2 drinks/day)
• History of significant neurological disease which may affect sensation, e.g., strokes, Multiple Sclerosis, or spinal cord disorder
• Change in neuropathy medications within the past 2 months
• Change in opioid, benzodiazepines, SSRIs or other sedating medications in the past 2 months

Conditions, which predispose to generalized neuropathy

• Abnormal thyroid function tests (by history)
• Past chemotherapy treatment

Other Contraindications:

• History of wrist or elbow fracture, past arm trauma, loss of fingers, scarring
• History of carpal tunnel release surgery or any other surgery on the arm or shoulder
• History of arthritis
• Use of any investigational drugs within the previous six months

Exclusion criteria

based on NCS within the past 2 years:

• Presence of isolated motor Median neuropathy (absence of sensory neuropathy on NCS or absence of sensory symptoms)
• Severe neuropathy symptoms leading to inability to tolerate acupuncture or QST
• Presence of Severe Carpal Tunnel Syndrome, defined as:

• Absent sensory nerve action potential recorded from the second or fifth digit.
• The amplitude of the compound muscle action potential recorded from the APB or ADM is less than 50% of normal (< 2.5 mv)
• Presence of Ulnar neuropathy
• Presence of Martin-Gruber anastomosis

Secondary Exclusion Criteria after WEEK 1 Baseline QST and NCS measurements:

• Failure to comply with QST due to inattentiveness, etc
• Hyperalgesia on QST
• Hypoalgesia on QST
• Inability to confirm diagnosis of mild-moderate CTS (normal NCS)
• Inability to tolerate NCS/QST
• Presence Severe CTS
• Pure Motor Median Neuropathy
• Ulnar Neuropathy