Carpal tunnel syndrome is one of the most common nerve entrapment conditions affecting the general population. Its prevalence varies, but it is estimated that nearly one in 20 adults is affected in Canada.
Carpal tunnel syndrome occurs due to median nerve compression in the carpal tunnel in the wrist. This compression affects the sensory and motor functions (in severe or untreated cases only) of the median nerve.
This compression results in numbness, weakness, wrist and hand pain and tingling sensations affecting mostly the index, thumb and middle finger which the median nerve controls.
This may affect the individual’s ability to grasp object firmly and to perform manual tasks effectively.
How to test for Carpal Tunnel Syndrome
Carpal tunnel tests are carried out on the hand to evaluate both the sensory and motor functions of the median nerve and to confirm carpal tunnel syndrome.
These tests are also called provocative tests because the response is intentionally induced.
A positive sign such as tingling sensations or numbness while carrying out any of the tests could indicate that you have carpal tunnel syndrome.
Here are the specific carpal tunnel syndrome tests:
Phalen’s test: Carpal tunnel Phalen’s test can be carried out at home.
The back of your hands is placed together in front with your wrist flexed and fingers pointing downwards. After assuming this position for a few minutes, the feeling of a tingling sensation shows a positive Phalen’s test for carpal tunnel syndrome.
Carpal compression test
You can perform this test at home. You apply pressure over the carpal tunnel in your hand. The aggravation of tingling sensation or numbness is suggestive of carpal tunnel syndrome.
The doctor uses a reflex hammer to tap on the median nerve in the hand. The associated tingling feeling in the fingers indicates a positive carpal tunnel Tinel test.
Two point discrimination test
This assesses your ability to clearly tell if 2 objects touching your skin are distinct. The doctor uses a two-point discriminator with prongs to test each finger. Each tool is placed on two points touching your finger’s skin and gradually advanced towards each other. The point at which the patient feels the 2 objects as one is noted. This is used to ascertain the extent of the median nerve functional damage.
Grip strength test
The physician uses a special tool called grip dynamometer to measure the strength of your grip. The presence of diminished grip strength is suggestive of a medina nerve compromise.
Scratch Collapse Test
The examiner scratches the suspected area of median nerve compression while the patient keeps the elbows flexed and tries to resist bilateral shoulder rotation. The brief loss of resistance in the affected area indicates a positive scratch collapse test. This test is particularly important as it can help diagnose a second median nerve entrapment syndrome called the Lacertus Syndrome.
Nerve conduction test
This is also called an electro-diagnostic test. The physician places a small electrode on the skin close to your elbow. The electrode transfers a mild electric current through the median nerve from the elbow to your fingers. A delay in the conduction of the current from your elbow to your fingers indicates carpal tunnel syndrome.
This is done to check the velocity of electrical impulses conducted from arm to the hand through the median nerve. A fine needle is inserted into muscles of the arm along the median nerve course and an electrical shock is passed through the needles while your arm is at rest and when you move your arm slightly. Carpal tunnel syndrome is detected when the speed of the electric signal is reduced.
Self examination vs Medical examination
A few of the carpal tunnel syndrome tests can be performed at home or by yourself but the performance and interpretation of the signs may be biased.
A study on carpal tunnel syndrome tests revealed that compression test responses among subjects tested were affected by factors such as the subject’s palm thickness.
The researchers also stated that provocative carpal tunnel test like Phalen’s test is not sufficient to make a diagnosis of carpal tunnel syndrome.
Therefore, it is recommended to seek a health professional’s assistance to perform a thorough holistic physical examination to rule out other causes of hand numbness or tingling sensation and to perform carpal tunnel confirmatory tests such as electromyography.
Dr Brutus is a seasoned hand surgeon with a proven track record of professional management of carpal tunnel syndrome clinically and surgically. Dr Brutus uses evidence based best practices that ensures proper examination of your hand and therapeutic relieve of carpal tunnel syndrome symptoms.
Carpal tunnel syndrome is one of the common causes of tingling sensation and numb feeling in the hand. Some carpal tunnel tests can be done at home while others are performed by a doctor. Experts recommend that doctors should examine and perform physical tests for patients suspected of having carpal tunnel syndrome because of the unreliability of self-performed tests