Quantitative Scratch Collapse Test Methodology With Handheld Dynamometer: Normative Upper-Extremity Force Data and...

Area of Science:

• Orthopedics
• Neurology
• Biomechanics

Background:

• The scratch collapse test (SCT) is used for diagnosing peripheral nerve compression syndromes.
• Current SCT protocols suffer from variable sensitivity and specificity due to inconsistent methods and subjective interpretation.
• Establishing objective, normative data is crucial for reliable clinical application.

Purpose of the Study:

• To establish normative upper-extremity force and torque values in healthy adults using a standardized quantitative scratch collapse test (SCT) approach.
• To assess the inter- and intra-examiner reliability of this standardized SCT protocol.

Main Methods:

• Healthy adults underwent maximal isometric shoulder external-rotation resistance testing.
• Two independent examiners conducted repeated trials on each participant's arm.
• Force and torque data were collected using handheld dynamometry, with reliability assessed across and within examiners.

Main Results:

• Normative force and torque values for both upper extremities were successfully obtained.
• Interrater reliability was found to be good to excellent.
• Intrarater reliability was excellent, with no significant systematic differences noted between examiners.

Conclusions:

• A quantitative SCT protocol utilizing handheld dynamometry yields reproducible normative values in healthy adults.
• This standardized method demonstrates high reliability, reducing examiner variability.
• The findings provide a strong foundation for future validation studies in patient populations and enhance objective clinical use of the SCT.