The Duncan test for carpal tunnel is a physical examination maneuver used to assess for carpal tunnel syndrome. Here's a breakdown of how it's performed and what a positive result indicates:
How the Duncan Test is Performed
The Duncan test is straightforward, involving pressure applied directly over the carpal tunnel:
- The examiner presses their thumbs firmly over the patient's carpal tunnel, located on the wrist.
- This pressure is maintained for 30 seconds.
Interpreting the Results
The test is considered positive if:
- The patient experiences pain or paresthesia (a tingling or prickling sensation) in the median nerve distribution of the hand within 30 seconds of pressure application. The median nerve distribution includes the thumb, index finger, middle finger, and part of the ring finger.
Significance of a Positive Test
A positive Duncan test suggests the potential presence of carpal tunnel syndrome. This occurs when the median nerve, which runs through the carpal tunnel in the wrist, is compressed. However, a positive test result should be further investigated by a qualified medical professional.
Duncan Test vs. Other Carpal Tunnel Tests
While the Duncan test is one method, there are other tests frequently used to assess for carpal tunnel syndrome:
- Phalen's Test: This involves flexing the wrists and holding them back-to-back for up to a minute. A positive test occurs when the same symptoms, such as pain and paresthesia, arise.
- Tinel's Test: This test involves tapping or lightly percussing over the carpal tunnel area. Tingling or paresthesia in the median nerve distribution is a positive result.
Summary of the Duncan Test
| Test Name | Procedure | Positive Result |
|---|---|---|
| Duncan Test | Examiner presses thumbs over the carpal tunnel and holds pressure for 30 seconds. | Pain or paresthesia in the median nerve distribution within 30 seconds of pressure application. |
It's important to note that clinical diagnosis of carpal tunnel syndrome usually involves a combination of physical examination tests (like the Duncan test), symptom history, and possibly nerve conduction studies (NCS). The Duncan Test is one piece of a more complete evaluation.
