Overview

The Flick Sign (FSI-14) is a clinical screening instrument used primarily to identify symptoms suggestive of Carpal Tunnel Syndrome (CTS). Rather than being a conventional psychometric questionnaire, the Flick Sign is based on a patient’s characteristic behavioral response: individuals experiencing median nerve compression often report that they instinctively shake, flick, or wave their hand in an attempt to relieve numbness, tingling, or pain, particularly during the night. This distinctive movement has been recognized as a simple yet clinically valuable indicator of CTS and is frequently incorporated into routine neurological and musculoskeletal examinations. Owing to its simplicity, non-invasive nature, and rapid administration, the Flick Sign is commonly used alongside other clinical tests and electrodiagnostic investigations to improve the diagnostic accuracy of median nerve entrapment disorders.

Objective

The primary objective of the Flick Sign (FSI-14) is to provide a rapid clinical assessment of symptoms associated with median nerve compression, particularly those characteristic of Carpal Tunnel Syndrome.

More specifically, the Flick Sign is designed to:

  • Identify patients exhibiting symptoms consistent with Carpal Tunnel Syndrome.
  • Detect characteristic nocturnal hand symptoms relieved by shaking or flicking the hand.
  • Support differential diagnosis between median nerve compression and other upper-limb disorders.
  • Complement neurological examination and electrodiagnostic testing.
  • Monitor symptom progression and treatment outcomes during conservative or surgical management.

Scale Structure

Although referred to here as the FSI-14, the traditional Flick Sign is not a multi-item psychometric scale but rather a clinical observation obtained during patient history taking. Patients are typically asked whether they experience numbness, tingling, pain, or discomfort in the hand and whether these symptoms are relieved by shaking or flicking the affected hand or wrist.

When incorporated into structured clinical assessment protocols, responses may be recorded across multiple symptom-related questions addressing:

  • Presence of nocturnal numbness or tingling.
  • Hand pain or paresthesia.
  • Frequency of symptom occurrence.
  • Symptom relief following the flicking movement.
  • Functional impairment during daily activities.
  • Distribution of sensory symptoms within the median nerve territory.

The uploaded description does not provide the actual 14 questionnaire items; therefore, the precise structure of the FSI-14 cannot be described beyond its clinical application.

Applications

The Flick Sign is widely used in orthopedic surgery, hand surgery, neurology, physical medicine and rehabilitation, occupational medicine, physiotherapy, and primary healthcare. It serves as a rapid bedside screening tool for patients presenting with hand numbness, paresthesia, pain, or weakness suggestive of median nerve compression.

Clinically, the Flick Sign assists healthcare professionals in identifying individuals who may require further diagnostic evaluation, including nerve conduction studies, electromyography, ultrasonography, or comprehensive neurological examination. In research, it has been employed as a clinical indicator of symptom severity, diagnostic accuracy, and treatment effectiveness in studies investigating conservative management, splinting, corticosteroid injections, and surgical decompression for Carpal Tunnel Syndrome.

Scoring and Psychometric Evaluation

Unlike standardized psychometric instruments, the Flick Sign does not employ a numerical scoring system. Assessment is based on the presence or absence of the characteristic flicking movement used by patients to relieve symptoms. A positive Flick Sign is recorded when the patient reports that shaking or flicking the hand alleviates numbness, tingling, or pain, whereas a negative Flick Sign indicates the absence of this characteristic behavior.

Because the Flick Sign represents a qualitative clinical finding, interpretation relies on integration with patient history, physical examination, provocative tests (such as Phalen’s test and Tinel’s sign), and electrodiagnostic investigations. Although several studies have reported favorable diagnostic sensitivity and specificity, the uploaded description does not provide numerical psychometric indices; therefore, specific reliability or diagnostic accuracy estimates cannot be presented.

Interpretation

A positive Flick Sign strongly suggests the presence of symptoms consistent with Carpal Tunnel Syndrome, particularly when accompanied by nocturnal paresthesia, pain within the median nerve distribution, and relief following hand shaking. Nevertheless, the Flick Sign should not be considered diagnostic in isolation, as similar symptoms may occur in cervical radiculopathy, peripheral neuropathies, or other musculoskeletal disorders. Consequently, the finding should always be interpreted within the broader clinical context and supplemented by additional neurological examination and confirmatory diagnostic testing.

References

Becker, J., Nora, D. B., Gomes, I., Stringari, F. F., Seitensus, R., Panosso, J. S., & Ehlers, J. A. C. (2002). An evaluation of gender, obesity, age and diabetes mellitus as risk factors for carpal tunnel syndrome. Clinical Neurophysiology, 113(9), 1429–1434.

Graham, B. (2008). The Value Added by Electrodiagnostic Testing in the Diagnosis of Carpal Tunnel Syndrome. Journal of Bone and Joint Surgery, 90(12), 2587–2593.

Wainner, R. S., Fritz, J. M., Irrgang, J. J., Delitto, A., Allison, S., & Boninger, M. L. (2005). Development of a Clinical Prediction Rule for the Diagnosis of Carpal Tunnel Syndrome. Archives of Physical Medicine and Rehabilitation, 86(4), 609–618.