A reverse Phalen test (Prayer test) is also used to evaluate the median nerve compression in the case of Carpal tunnel syndrome.
The patient is asked to keep both hands with the wrists in complete extension for 60 seconds (wrist and finger extension).
This position increases the pressure in the carpal tunnel. Paresthesia in the region supplied by the median nerve is a sign of carpal tunnel syndrome.
The reverse Phalen test is less reliable than the Phalen test.
Sensitivity & Specificity
The original Phalen test has demonstrated a a high sensitivity and a moderate specificity making it moderately acceptable for use in clinical practice:1
Specificity: 47 %
While in Reverse Phalen Test, a study by de Krom and colleagues2 found the test to have a sensitivity of 41 % and a specificity of 55 %
Carpal tunnel syndrome
Carpal tunnel syndrome is a cause of chronic wrist pain and functional impairment of the hand. It results from an ischemic compression of the median nerve at the wrist as it passes through the carpal tunnel.
Compression of the nerve in the carpal tunnel is compounded by an increase in synovial fluid pressure and tendon tension, which decreases the available volume.
The compression of the median nerve may result from a wide variety of factors that compromise the tunnel space such as:
fluid retention, which occurs during pregnancy, Infection and conditions such as renal dysfunction.
In addition, several disease conditions, such as gout or pseudogout, acromegaly, or amyotrophy can also decrease the tunnel size.
About half of the cases of Carpal tunnel syndrome are related to repetitive and cumulative trauma in the workplace.
Carpal tunnel syndrome is the most common compression neuropathy, with a prevalence of 9.2 % in women and 0.6 % in men.
The initial characteristic features of Carpal tunnel syndrome include intermittent pain and paresthesias in the median nerve distribution of the hand which progressively become more persistent as the condition progresses.
Katz JN, Larson MG, Sabra A, et al: The carpal tunnel syndrome: diagnostic utility of the history and physical examination findings. Ann Intern Med 112:321–327, 1990. PMID: 2306060
de Krom MC, Knipschild PG, Kester AD, et al: Efficacy of provocative tests for diagnosis of carpal tunnel syndrome. Lancet 335:393–395, 1990.
Werner RA, Bir C, Armstrong TJ: Reverse Phalen’s maneuver as an aid in diagnosing carpal tunnel syndrome. Arch Phys Med Rehabil 75:783–786, 1994.